Section 1
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Section 1
(50 cards)
polymer
large compound formed from combinations of many monomers
hydrolysis
a chemical process in which a compound is broken down and changed into other compounds by taking up the elements of water
repetitive DNA
nucleotide sequences, usually noncoding, that are present in many copies in a eukaryotic genome.
metabolic rate
the amount of energy an animal uses in a unit of time
crossing over
the interchange of sections between pairing homologous chromosomes during the prophase of meiosis
epiphyte
plant that is not rooted in soil but instead grows directly on the body of another plant
chemiosmosis
a process for synthesizing ATP using the energy of an electrochemical gradient and the ATP synthase enzyme.
transposons
small mobile DNA segments
positive feedback
a physiological control mechanism in which a change in a variable triggers mechanisms that amplify the change
gametes
reproductive cells, have only half the number of chromosomes as body cells
thermoregulation
the maintenance of body temperature within a range that enables cells to function efficiently
meiosis
a process in cell division during which the number of chromosomes decreases to half the original number by two divisions of the nucleus, which results in the production of sex cells
diatoms
unicellular algae that have a unique glass-like wall made of hydrated silica embedded in an organic matrix
parthenogenesis
asexual reproduction in which females produce offspring from unfertilized eggs
phosphorylation
the transfer of a phosphate group, usually from ATP, to a molecule. Nearly all cellular work depends on ATP energizing other molecules by phosphorylation
inflammatory response
nonspecific defense against infection, characterized by redness, heat, swelling, and pain
nitrogen fixation
process of converting nitrogen gas into nitrogen compounds that plants can absorb and use (ammonia)
fermentation
the process by which cells break down molecules to release energy without using oxygen
natural selection
process by which individuals that are better suited to their environment survive and reproduce most successfully
adaptations
the behaviors and physical characteristics that allow organisms to live successfully in their environments
symmetry
the way an animal's body parts match up around a point or central line
cephalization
the concentration of nerve tissue and sensory organs at the anterior end of an organism
phospholipids
a molecule that is a constituent of the inner bilayer of biological membranes, having a polar, hydrophilic head and a nonpolar, hydrophobic tail
homeobox
one of various similar homeotic genes that are involved in bodily segmentation during embryonic development
negative feedback
a mechanism of response in which a stimulus initiates reactions that reduce the stimulus
cellular respiration
process that releases energy by breaking down glucose and other food molecules in the presence of oxygen
genome project
Research and technology development effort aimed at mapping and sequencing some or all of the genome of human beings and other organisms
amoeba
A type of protist characterized by great flexibility and the presence of pseudopodia
mutations
random errors in gene replication that lead to a change in the sequence of nucleotides; the source of all genetic diversity
RNA splicing
process by which the introns are removed from RNA transcripts and the remaining exons are joined together
acquired immunity
immunity that the body develops after it overcomes a disease, or through inoculation (such as vaccination)
gastrula
an embryonic stage in animal development encompassing the formation of three layers: ectoderm, mesoderm, and endoderm
coelom
fluid-filled body cavity lined with mesoderm
codons
a three-nucleotide sequence of DNA or mRNA that specifies a particular amino acid or termination signal; the basic unit of the genetic code.
transcription
process in which part of the nucleotide sequence of DNA is copied into a complementary sequence in mRNA
sexual reproduction
process in which genetic material from two parents combines and produces offspring that differ genetically from either parent
crop rotation
the system of growing a different crop in a field each year to preserve the fertility of the land
sustainable agriculture
farming method that preserves long-term productivity of land and minimizes pollution
epithelium
membranous tissue covering internal organs and other internal surfaces of the body
vestigial structures
remnant of a structure that may have had an important function in a species' ancestors, but has no clear function in the modern species
inductive reasoning
reasoning based on observed patterns
emergent properties
new properties that emerge with each step upward in the hierarchy of life, owing to the arrangement and interactions of parts as complexity increases
ciliates
a group of protozoans that move by waving tiny, hair-like organelles called cilia
macrophages
engulf bacteria and cellular debris by phagocytosis
protists
single-celled or simple multicellular eukaryotic organisms that generally do not fit in any other kingdom
enzyme
protein that acts as a biological catalyst
convergent evolution
process by which unrelated organisms independently evolve similarities when adapting to similar environments
somatic cell
cell that makes up all of the body tissues and organs, except gametes
antigen
substance that triggers an immune response
physiology
processes and functions of an organism
Section 2
(50 cards)
mitochondria
powerhouse of the cell, produces energy (ATP) from oxygen and sugar
ribosomes
non membrane bounded organelles responsible for protein synthesis
vascular tissue
tissue that conducts water and nutrients through the plant body in higher plants
pleiotrophy
the ability of a single gene to have multiple effects
community
a group of interdependent organisms inhabiting the same region and interacting with each other
cell differentiation
the process of cell specialization
thylakoids
A flattened membrane sac inside the chloroplast, used to convert light energy to chemical energy
vasoconstriction
narrowing of blood vessels
eukaryotic cells
contain a nucleus and other organelles that are bound by membranes
operon
a group of genes that operate together
mimicry
the resemblance of an animal species to another species or to natural objects
invertebrates
animals without a backbone
CAM plants
store the organic acids made at night in vacuoles and use them for photosynthesis during the day when stomata are closed
compound
a substance formed by chemical union of two or more elements or ingredients in definite proportion by weight
sinoatrial node
the heart's pacemaker, located in the wall of the right atrium
echinoderms
invertebrates with an internal skeleton and a system of fluid-filled tubes called a water vascular system
hermaphrodite
individual that has both male and female reproductive organs
keystone species
a species that influences the survival of many other species in an ecosystem
covalent bond
a chemical bond that involves sharing a pair of electrons between atoms in a molecule
niche
the status of an organism within its environment and community (affecting its survival as a species)
bryophyte
nonvascular plant; examples are mosses and their relatives
prokaryotic
describes a cell that does not have a nucleus or anyother membrane-covered organelles; also called bacteria
sliding filament model
The theory explaining how muscle contracts, based on change within a sarcomere, the basic unit of muscle organization, stating that thin (actin) filaments slide across thick (myosin) filaments, shortening the sarcomere; the shortening of all sarcomeres in a myofibril shortens the entire myofibril
ion
atom that has a positive or negative charge
roots
underground organs that absorb water and minerals
smooth muscle
a muscle that contracts without conscious control and found in walls of internal organs such as stomach and intestine and bladder and blood vessels (excluding the heart)
gene flow
movement of alleles into or out of a population due to the migration of individuals to or from the population
homeotic genes
any of the genes that control the overall body plan of animals and plants by controlling the developmental fate of groups of cells
exoskeleton
the exterior protective or supporting structure or shell of many animals (especially invertebrates) including bony or horny parts such as nails or scales or hoofs
platelets
tiny, disk-shaped bodies in the blood, important in blood clot formation
heterozygous
having two different alleles for a trait
endometrium
inner lining of the uterus
perception
the process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events
gametogenesis
the development and maturation of sex cells through meiosis
fruit
a mature ovary of a flower that protects dormant seeds and aids in their dispersal
complete metamorphosis
the transformation of a larva into an adult that looks very different, and often functions very differently in its environment, than the larva
dormancy
period of time during which a plant embryo is alive but not growing
hybridization
the act of mixing different species or varieties of animals or plants and thus to produce hybrids
pollen grain
male gametophyte in seed plants
geographic variation
differences in the genetic composition of separate populations
Hardy-Weinberg equilibrium
theory of a stable, nonevolving population in which frequency of alleles do not change; only occurs in large, isolated populations with random mating, and no natural selection or mutations
disruptive selection
form of natural selection in which a single curve splits into two; occurs when individuals at the upper and lower ends of a distribution curve have higher fitness than individuals near the middle
hydrogen bond
weak chemical bond formed by the attraction of positively charged hydrogen atoms to other negatively charged atoms
hemoglobin
iron-containing protein in red blood cells that transports oxygen from the lungs to the tissues of the body
oncogenes
cancer-causing genes
autotrophs
organisms that make their own food
photosynthesis
process by which plants and some other organisms use light energy to convert water and carbon dioxide into oxygen and high-energy carbohydrates such as sugars and starches
complete flowers
a flower that has all four basic floral organs: sepals, petals, stamens, and carpals
alleles
different forms of a gene
seed
embryo of a living plant that is encased in a protective covering and surrounded by a food supply
Section 3
(50 cards)
hormones
chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissues
protein kinase
an enzyme that transfers phosphate groups from ATP to a protein
signal transduction pathway
a series of steps linking a mechanical or chemical stimulus to a specific cellular response
peripheral proteins
protein appendages loosely bound to the surface of the membrane and not embedded in the lipid bilayer
amniotes
their embryos are protected by external membranes
endospore
type of spore formed when a bacterium produces a thick internal wall that encloses its DNA and a portion of its cytoplasm
placentals
mammals who have offspring who develop inside placenta (humans)
adhesion
an attraction between molecules of different substances
endothermic
dependent on or capable of the internal generation of heat
angiosperm
a flowering plant, which forms seeds inside a protective chamber called an ovary
vaccine
a substance that stimulates the body to produce chemicals that destroy viruses or bacteria
pandemic
disease that occurs over a wide geographic area and affects a very high proportion of the population
flower
the reproductive structure of an angiosperm
pheromones
chemicals secreted by animal species that influence the behavior of other animals of the same species
pathogens
disease producing microorganisms
caspid
protein covering that surrounds a virus
exponential growth
growth of a population that multiplies by a constant factor at constant time intervals
pollination
the transfer of pollen from male reproductive structures to female reproductive structures in plants
insulin
protein hormone that helps to decrease blood sugar
polar molecule
molecule with an unequal distribution of charge, resulting in the molecule having a positive end and a negative end
hydrophobic
avoids water molecules
barr body
Inactivated X chromosome in females
linkage map
a genetic map based on the frequencies of recombination between markers during crossing over of homologous chromosomes
cohesion
attraction between molecules of the same substance
prions
infectious protein particles that do not have a genome
hypertonic
when comparing two solutions, the solution with the greater concentration of solutes
nondisjunction
error in meiosis in which homologous chromosomes fail to separate
cleavage
the process of cytokinesis in animal cells, characterized by pinching of the plasma membrane; specifically, the succession of rapid cell divisions without growth during early embryonic development that converts the zygote into a ball of cells
phototropism
tendency of plants to grow toward a source of light
osmosis
diffusion of water through a selectively permeable membrane
habituation
decreasing responsiveness with repeated stimulation
chordates
an animal phylum that has a notochord, a dorsal hollow nerve cord, and gill slits at some time in its life cycle
altruism
unselfish regard for the welfare of others
endocytosis
process by which a cell takes in a substance by surrounding it with the cell membrane
germ layer
any of the 3 layers of cells differentiated in embryos following gastrulation
endocrine glands
glands of the endocrine system that release hormones into the bloodstream
emigration
movement of individuals out of an area
conjugation
form of sexual reproduction in which paramecia and some prokaryotes exchange genetic information
migration
movement from one place to another
symbiosis
living together in mutually helpful association of two dissimilar organisms
acrosomal reaction
the discharge of hydrolytic enzymes from the acrosome, when the sperm contacts an egg
ligand
a molecule that binds specifically to a receptor site of another molecule
gibberellins
Plant hormones that promote stem and leaf elongation
hypothalamus
a neural structure lying below the thalamus; directs eating, drinking, body temperature; helps govern the endocrine system via the pituitary gland, and is linked to emotion
survivorship curve
graph showing the number of survivors in different age groups for a particular species
demography
study of populations
kinesis
a change in activity or turning rate in response to a stimulus
endosperm
the food supply for a plant embryo found inside a seed
viviparous
producing living young (not eggs)
sex-linked gene
gene located on the X or Y chromosome
Section 4
(50 cards)
short term memory
activated memory that holds a few items briefly, before information is stored or forgotten
cancer
a disease in which abnormal cells multiply out of control, spread into surrounding tissues and other body parts, and disrupt normal functioning of one or more organs
circadian rhythms
the 24-hour biological cycles found in humans and many other species
antidiuretic hormone
hormone secreted by the posterior pituitary gland to prevent the kidneys from expelling too much water
endergonic reaction
a non-spontaneous chemical reaction in which free energy is absorbed from the surroundings
half-life
the period of time in which half of a radioactive substance decays
cerebral cortex
the intricate fabric of interconnected neural cells that covers the cerebral hemispheres; the body's ultimate control and information-processing center
cladistics
a system of phylogenetic analysis that uses shared and derived characters as the only criteria for grouping taxa
telomerase
an enzyme that catalyzes the lengthening of telomeres; the enzyme includes a molecule of RNA that serves as a template for new telomere segments
greenhouse effect
process by which atmospheric gases trap heat close to Earth's surface and prevent it from escaping into space
chromatin
long strands of DNA found in the eukaryotic cell nucleus; condense to form chromosomes
adenosine triphosphate
the molecule that stores energy that can be used by the cell
substrate
specific reactant acted on by an enzyme
okazaki fragments
short fragments of DNA that are a result of the synthesis of the lagging strand during DNA replication
protobionts
collections of abiotically produced molecules surrounded by a membrane-like structure
organic chemistry
the chemistry of compounds containing carbon (originally defined as the chemistry of substances produced by living organisms but now extended to substances synthesized artificially)
entropy
a thermodynamic quantity representing the unavailability of a system's thermal energy for conversion into mechanical work, often interpreted as the degree of disorder or randomness in the system
species
taxonomic group whose members can interbreed
plasmids
the small, circular segments of DNA that are found in bacteria and that stay sparate from the bacterial chromosomes; used in genetic engineering
producers
organisms that make their own food
allopatric speciation
the formation of new species in populations that are geographically isolated from one another
pangea
the name of the single landmass that broke apart 200 million years ago and gave rise to today's continents
urea
the chief solid component of mammalian urine
nephron
any of the small tubules that are the excretory units of the vertebrate kidney
biological magnification
increasing concentration of a harmful substance in organisms at higher trophic levels in a food chain or food web
binary fission
type of asexual reproduction in which an organism replicates its DNA and divides in half, producing two identical daughter cells
transformation
modification of a cell or bacterium by the uptake and incorporation of exogenous DNA
gel electrophoresis
the separation of nucleic acids or proteins, on the basis of their size and electrical charge, by measuring their rate of movement through an electrical field in a gel
microevolution
evolution resulting from small specific genetic changes that can lead to a new subspecies
ecology
the branch of biology concerned with the relations between organisms and their environment
club fungi
a type of fungus that bears reproductive sperm externally, on club-shaped structures (basidia) at the tips of hyphae
endosymbiosis
process through which early prokaryotic cells are thought to have engulfed other, smaller cells and eventually incorporated them as organelles; these cells evolved into modern-day eukaryotes
mitosis
in eukaryotic cells, a process of cell division that forms two new nuclei, each of which has the same number of chromosomes
polyploidy
the condition in which an organism has extra sets of chromosomes
lichen
symbiotic association between a fungus and a photosynthetic organism
reflexes
an automatic and often inborn response to a stimulus that involves a nerve impulse
amygdale
brain region that regulates emotions
recombinant DNA
DNA produced by combining DNA from different sources
molds
a type of fungus that consists of chains of cells and appears as a fuzzy mass of thin filaments in culture
hydrocarbons
organic molecules that are composed of only carbon and hydrogen
catabolic
A process in which large molecules are broken down
taxonomy
study of the general principles of scientific classification
pre-zygotic barriers
a reproductive barrier that impedes mating between species or hinders fertilization if interspecific mating is attempted
hyphae
the branching, threadlike tubes that make up the bodies of multicellular fungi
isomers
compounds with the same formula but different structure
polymerase chain reaction
technique that allows molecular biologists to make many copies of a particular gene
apoptosis
a type of cell death in which the cell uses specialized cellular machinery to kill itself
helicases
enzymes that untwist the double helix at the replication forks
excretion
the process by which wastes are removed from the body
phylogeny
the sequence of events involved in the evolutionary development of a species or taxonomic group of organisms
Section 5
(50 cards)
stem
supporting structure that connects roots and leaves and carries water and nutrients between them
carnivore
organism that obtains energy by eating animals
bioremediation
the use of living organisms to detoxify and restore polluted and degraded ecosystems
solute
Something dissolved in a solution.
biotic factor
all the living things in an ecosystem
disulphide bridges
Reinforce tertiary structure.
starch
Storage polysaccharide of plants.
polar
Molecule with partial charges. Mixes with water.
dispersal
the movement of organisms from one place to another
Fredrick Sanger
Determined amino acid sequence of proteins.
-ose
Suffix of a sugar.
aquaporins
a transport protein in the plasma membrane of a plant or animal cell that specifically facilitates the diffusion of water across the membrane
neurotransmitters
chemical messengers that traverse the synaptic gaps between neurons
cellulose
Carbohydrate component of plant cell walls.
cholesterol
Steroid common in cell membranes, also in many hormones.
introduced species
nonnative species that are either intentionally or unintentionally transported to a new habitat
electronegativity
Attraction of an atom for electrons in a covalent bond.
tryiacylglycerol
Glycerol and three fatty acids.
steroids
Made of four rings of carbon.
ganglia
groups of nerve cell bodies that coordinate incoming and outgoing nerve signals
glycogen
Extremely branched polymer of glucose.
turgid
swollen and distended or congested
minimum viable population
the smallest population size at which a species is able to sustain its numbers and survive
solvent
Dissolving agent of a solution.
primary structure
Chain of amino acids.
action potential
a neural impulse; a brief electrical charge that travels down an axon; the action potential is generated by the movement of positively charged atoms in and out of channels in the axon's membrane
adhesion
Water molecules sticking to other surfaces.
alpha glucose
Monomer for starch and glycogen.
isomers
Same atoms but different arrangement.
secondary structure
Either an alpha helix or beta pleated sheet.
cline
a graded change in a trait along a geographic axis
biomes
a broad, regional type of ecosystem characterized by distinctive climate and soil conditions and a distinctive kind of biological community adapted to those conditions
chitin
Polysaccharide found in arthropod exoskeletons and fungal cell walls.
plasmodesmata
channels through cell walls that connect the cytoplasms of adjacent cells
synaptic cleft
space between two connecting neurons where neurotransmitters are released
cohesion
Water molecules sticking to each other.
structural isomers
Differ in arrangement of atoms.
beta glucose
Monomer for cellulose and chitin.
peptide bond
Bonds that connect amino acids.
nonpolar
No partial charges. Do not mix with water.
transpiration
the emission of water vapor from the leaves of plants
geometric isomer
Differ in arrangement around a double bond.
peristalsis
the process of wave-like muscle contractions of the alimentary tract that moves food along
enantiomers
Structures that are like a mirror-image.
stomata
the small openings on the undersides of most leaves through which oxygen and carbon dioxide can move
conservation
the preservation and careful management of the environment and of natural resources
tissue
a part of an organism consisting of an aggregate of cells having a similar structure and function
malnourishment
a nutritional imbalance caused by lack of specific dietary components or inability to absorb or utilize essential nutrients
apical meristems
embryonic plant tissue in the tips of roots and in the buds of shoots that supplies cells for the plant to grow in length
vitamins
compounds that help regulate many vital body processes, including the digestion, absorption, and metabolism of other nutrients
Section 6
(50 cards)
phosphodiester bonds
Bonds between phosphate group and pentose sugar in nucleic acids.
macroevolution
Evolutionary change above the species level.
tertiary structure
Results from interactions between side chains.
digestion
To break apart.
speciation
Origin of new species and the source of biological diversity.
artificial selection
Humans modifying species for desired traits through selective breeding.
fitness
Individuals whose inherited traits confer an advantage have a better chance of surviving in a given environment and will leave more offspring.
homology
Similarity resulting from common ancestry.
evolutionary adaptation
An accumulation of inherited characteristics that enhance organisms' ability to survive and reproduce in specific environments.
purines
Bases with a double-ring structure.
geographic variation
Difference in variation between population subgroups in different areas.
bottleneck effect
When a population has been dramatically reduced, and the gene pool is no longer reflective of the original population's.
sexual dimorphism
Differences between the sexes in secondary sexual characteristics.
stabilizing selection
Shift that favors the mean.
allele frequency
Proportion of an allele in a gene pool.
quaternary structure
Results from two or more polypeptide subunits.
genetic variation
Heritable variations in a population.
population
Group of individuals of the same species living in the same area.
sexual recombination
Crossing over and shuffling of genes during meiosis.
founder effect
When a small number of individuals colonize a new area; the new gene pool is not reflective of original population.
comparative embryology
Embryos of vertebrates share many anatomical homologies.
genetic drift
Change in allele frequencies due to chance.
natural selection
A population can change over time if individuals with more fit traits leave more offspring than less fit individuals.
anabolism
Metabolic pathways that construct molecules, requiring energy.
homologous structures
Same structure, different function. Comes from common ancestor.
microevolution
Change in genetic makeup of a population from generation to generation.
relative fitness
Fitness of a particular genotype.
decent with modification
Darwin's way of referring to evolution.
vestigial structures
Are little or no importance to organism, but remain from an ancestor.
population genetics
Study of allele frequency distribution and change under the influence of evolutionary processes.
mutation
Changes in the nucleotide sequence in DNA.
gene pool
All the genes in a given population at a given time.
quantitative characteristics
Characteristics that vary along a continuum, usually due to influence of two or more genes.
sexual selection
Natural selection for mating success.
directional selection
Shift toward a favorable variation.
biogeography
Geographic distribution of species.
heterozygous advantage
Maintains recessive alleles in a population,
gene flow
When a population gains or loses alleles., movement of alleles into or out of a population due to the migration of individuals to or from the population.
catabolism
Metabolic pathways that break down molecules, releasing energy.
biological species concept
Species is a group of populations whose members have the potential to produce fertile offspring.
hydrolysis
Reaction where water split into two hydrogens and one oxygen; this breaks a polymer.
MRSA
Methicillin-resistant Staphylococcus aureus.
synthesis
To put together.
dehydration synthesis
Condensation reaction where molecules are connected by loss of a water molecule.
-in
Suffix of a protein.
discrete characteristics
Characteristics that are classified on an either-or basis, determined by a single gene locus.
pyrimidines
Bases with a single-ring structure.
disruptive selection
Shift toward the extremes.
Hardy-Weinberg Theorem
Helps measure changes in allele frequencies over time . Provides an "ideal" population to use as a basis of comparison.
cline
A graded change in a trait along a geographic axis.
Section 7
(50 cards)
autopolyploid
Having more than two sets of chromosomes from a single species.
shared derived character
Evolutionary novelty unique to that clade.
reduced hybrid viability
When the genes of different species interact and impair hybrid development.
specific epithet
Second part of scientific name.
shared primitive character
Trait shared beyond the taxon.
Miller and Urey Experiment
Experiment that found that organic molecules can form in a strongly reducing atmosphere.
temporal isolation
When two species breed at different times of day, season, or years.
homoplasies
Analogous structures that have evolved independently.
clade
A taxonomic grouping that includes only a single ancestor and all of its descendants.
heterochrony
Change in the rate or timing of a developmental event ; an organism's shape depends on relative growth rate of body parts.
postzygotic barriers
Barriers that prevent the hybrid zygote from becoming a fertile adult.
outgroups
Species or group of species closely related to the ingroup.
homeotic genes
Genes that determine basic features of where a body part is.
mechanical isolation
Morphological differences prevent fertilization.
reproductive isolation
Barriers that impede members of two different species fro producing fertile offspring.
behavioral isolation
Incompatible courtship rituals, pheromones, or bird songs.
orthologous genes
Homologous genes passed in a straight line from one generation to the next.
prezygotic barriers
Barriers that impede mating or hinder fertilization.
allometric growth
Proportioning that gives a body a specific form.
gametic isolation
When sperm can't fertilize the eggs.
analogy
Anatomical similarity due to convergent evolution.
adaptive radiation
Evolution of many new species from a common ancestor as a result of introduction to new environments.
paraphyletic group
A monophyletic group in which some descendants of the common ancestor have been removed.
allopolyploid
Sterile hybrid is changed to a fertile polyploid due to mutation ; fertile with each other, but not parent species.
hybrid breakdown
Hybrid is fertile, but when they breed the next generation is sterile.
allopatric speciation
When a population is divided; leads to speciation.
monophyletic group
A taxonomic grouping that includes an ancestral species and all of its descendants.
phylogenetic trees
Branching diagrams that depict hypotheses about evolutionary relationships.
paralogous genes
Homologous genes that are found in the same genome as a result of gene duplication.
maximum likelihood
A principle that states that when considering multiple phylogenetic hypotheses, one should take into account the one that reflects the most likely sequence of evolutionary events, given certain rules about how DNA changes over time.
gradualism
A model of evolution in which gradual change over a long period of time leads to biological diversity.
cladogram
Diagram that shows patterns of shared characteristics.
gene families
Groups of related genes in an organism's genome.
genus
First part of scientific name.
habitat isolation
When two species encounter each other only rarely.
phylograms
Diagram in which the length of a branch reflects number of changes in a DNA sequence.
reduced hybrid fertility
Sterile hybrids due to uneven chromosome number.
cladistics
A phylogenetic classification system that uses shared derived characters and ancestry as the sole criterion for grouping taxa.
maximum parsimony
"Occam's Razor." A principle that states that when considering multiple explanations for an observation, one should first investigate the simplest explanation that is consistent with the facts.
sympatric speciation
Speciation without a divided population.
punctuated equilibrium
A model of evolution in which a new species will change the most as it buds from a parent species, and then will change little for the rest of its existence.
ultrametric trees
Diagram in which length of a branch reflects amounts of actual time.
bionomial nomenclature
Scientific name.
polyploidy
In plants, the result of an extra set of chromosomes during cell division.
protobionts
Aggregates of abiotically produced molecules surrounded by a membrane.
Hox genes
Class of homeotic genes. Changes in these genes can have a profound impact on morphology.
systematics
Analytical approach to understanding the diversity and relationships of present and past organisms.
phylogeny
Evolutionary history of a species or group of species.
polyphyletic group
A taxonomic grouping consisting of several species that lack a common ancestor (more work is needed to uncover species that tie them together into a monophyletic clade).
taxonomy
A classification of organisms into groups based on similarities.
Section 8
(50 cards)
serial endosymbiosis
Sequence of endosymbiotic events that led to an ancestral eukaryote.
microclimate
Very fine patterns of climate influenced by features of the environment such as shade ares and wind patterns.
actual range
Area an organism actually occupies.
methanogens
Archaea that release methane, a greenhouse gas.
taxis
Movement toward or away from a stimulus.
cocci
Spherical bacteria.
Gram stain
Used to classify prokaryotes based on cell wall composition. Important for antibiotics; some antibiotics work on one but not the other.
dispersal
Movement of individuals away from centers of high population density or their area of origin.
Gram-negative bacteria
Bacteria that have complex cell walls with less peptidoglycan but with lipopolysaccharides. Very toxic and hard to treat.
biota
Biotic factors.
biogeographic realms
Broad patterns of distribution due to continental drift and barriers such as deserts and mountain ranges.
antibiotic resistance
Resistance evolving rapidly in many species of prokaryotes due to overuse of antibiotics, especially in agriculture.
lyse
Cell bursting.
bacilli
Rod-shaped bacteria.
conjugation
In bacteria, the direct transfer of DNA between two cells that are temporarily joined.
biome
Major types of ecological association that occupy broad geographic regions.
potential range
An area where an organism could potentially survive and reproduce.
plasmids
Small rings of DNA found naturally in some bacterial cells in addition to the main bacterial chromosome. Can contain genes for antibiotic resistance, or other "contingency" functions.
chemoautotrophs
Organisms that use hydrogen sulfide or other chemicals as energy source instead of light.
Gram-positive bacteria
Bacteria that have simple cell walls with much peptidoglycan.
antibiotics
Interfere with production of peptidoglycan; harm bacteria but not eukaryotes.
archaea
Domain of unicellular prokaryotes that have cell walls lacking peptidoglycan. Like eukaryotes, DNA contains histone proteins.
photoautotrophs
Photosynthetic bacteria.
stromatolites
Oldest known fossils formed from many layers of bacteria and sediment.
population density
The size of the population within a particular unit of space.
macroclimate
Patterns on the global, regional and local level.
extremophiles
Archaea that live in extreme environments.
abiotic factors
Nonliving components of environment.
pilli
Hollow tubes used to move cells or exchange DNA between bacteria by conjunction.
species transplant
Movement of a species to areas where it was previously absent.
ecology
Study of interactions between organisms and the environment.
liposomes
Membrane-bound droplets that form when lipids are added to water.
thermophiles
Archaea that thrive in very hot environments, such as volcanic springs.
capsule
Covers the cell wall in prokaryotes.
endosymbiotic theory
Ancestors of mitochondria and plastids was prokaryotes that came to live in a host cell.
community
All species that inhabit an area.
endospore
A thick-walled protective spore that forms inside a bacterial cell and resists harsh conditions.
genetic annealing
Horizontal gene transfer between different bacteria and archae.
peptidoglycan
Cell wall of prokaryotes, but NOT ARCHAEA. Made of a sugar polymer and polypeptide.
radioisotopes
Isotopes that have unstable nuclei and undergo radioactive decay.
biosphere
The sum of all ecosystems.
plasmolyze
When the membrane shrinks away from the cell wall as a result of water loss.
spirilla
Spiral bacteria.
dispersion
Pattern of spacing among individuals.
climate
Prevailing weather conditions of an area.
radiometric dating
Dating using decay of radioactive isotopes.
biotic factors
All the plant and animal life of a particular region.
turnover
Seasonal changes in warm and cool water layers in lakes.
the three-domain system
Domains Bacteria, Archae, and Eukarya.
colonies
Collections of autonomously replicating cells.
Section 9
(50 cards)
uniform dispersion
The pattern in which individuals are equally spaced throughout a habitat.
territoriality
Defense of a space against encroachment by other individuals.
Type II
Curve that represents constant death rate over lifespan small animals and invertebrates.
per capita death rate
Expected number of deaths in a population in a specified period of time.
Batesian mimicry
Species mimics the appearance of an unpalatable or harmful.
niche
Sum total of a species' use of the biotic and abiotic resources; an organism's "role".
cohort
A group of individuals of the same age.
resource partitioning
Differentiation of niches that enables similar species to coexist.
zero population growth (ZPG)
When per capita birth and death rates are equal. (r = 0)
density-dependent regulation
When birth or death rates do change with population density.
iteroparity
Repeated reproduction.
reproductive rates
Study of females to determine reproductive output and how it varies with age of female.
life tables
Age-specific summaries of survival patterns of a population.
Type III
Curve that drops sharply at the start then levels off once individuals reach a critical age, as seen in organisms that produce large numbers of offspring.
life expectancy at birth
Predicted average length of life at birth.
density-independent regulation
When birth or death rates do not change with population density.
reproductive table (fertility schedule)
Age-specific summary of reproductive rates in a population.
clumped dispersion
The most common pattern of dispersion; individuals aggregated in patches.
competitive exclusion
Strong competition can lead to local elimination of one of the species.
exponential growth
Population increase under ideal conditions, when r > 0. Forms a J-shaped curve.
big-bang reproduction
Species that have only a single reproductive opportunity, such as agave and salmon.
aposematic coloration
Bright warning colors in animals with a chemical defense.
cryptic coloration
Camouflage; makes an organism difficult to spot.
Competitive Exclusion Principle
Two species competing for same limiting resource cannot coexist in one place; one species will have an advantage that will eventually lead to competitive exclusion
survivorship curves
Graph of the proportion of a cohort still alive at each age.
Type I
Curve that shows low death rate at early and mid-life and drops at old age, as seen in humans and large animals.
interspecific competition
Species compete for a limiting resource. (-/-)
age structure
Relative number of individuals at each age.
per capita offspring
Average number of offspring produced per individual during a specified period of time.
repeated reproduction
Species that reproduce over and over.
reproductive rate
Difference between per capita birth and per capita death rates.
realized niche
The niche species actually occupies.
carrying capacity (K)
Maximum population size that a particular environment can support.
K - selected species
Life history traits sensitive to population density. Small number of large offspring, extensive parental care, repeated reproduction.
demography
Study of vital statistics of a population and how they change over time.
metapopulation
When many populations are linked.
ecological footprint
Land and water area appropriated by each nation as a resource to consume or to absorb the waste it generates.
r-selected species
Life history traits maximize reproductive success in uncrowded environments. Many small offspring that mature quickly, little if any parental care.
mark-recapture method
A sampling technique used to estimate wildlife populations.
logistic growth
When limiting factors restrict size of population to the carrying capacity of the environment. Forms an S-shaped curve.
immigration
New individuals moving into population. Increases population size.
demographic transition
Movement from a high birth rate, high death rate to a low birth rate, low death rate.
random dispersion
Random spacing of individuals of the same species within an area.
ecological niche
Sum total of a species' use of the biotic and abiotic resources.
life history
Traits that affect an organism's schedule of reproduction and survival.
semelparity
Big-bang reproduction.
character displacement
Tendency of characteristics to be more divergent in sympatric populations than allopatric populations.
infant mortality
Number of infant deaths per thousand live births.
fundamental niche
The niche species could potentially occupy.
emigration
Movement out of population. Decreases population size.
Section 10
(50 cards)
invasive species
Species generally introduced by humans, that take hold outside of their native range.
secondary succession
Succession when an existing community has been cleared, but soil left intact.
detritivores
Obtain energy from detritus.
dominant species
Species that are the most abundant or have the most biomass.
eutrophication
Sewage and fertilizer runoff adds nutrients to lakes; phytoplankton decreases and cyanobacteria increases.
equatorial-polar gradients
Species diversity highest at equator, decreases toward poles.
ecosystem
Consists of all the organisms living in a community as well as all the abiotic factors with which they interact.
gross primary production (GPP)
Amount of light energy that is converted to chemical energy by photosynthesis.
island equilibrium model
Islands great for study due to isolation and limited size; can study species diversity and extinction rates.
coevolution
Reciprocal evolutionary adaptations of two interacting species.
disturbance
An event, such as storm, fire, flood, drought, overgrazing or human activity, that changes a community and alters resource availability.
food web
Linked food chains.
energy hypothesis
Length of a food chain is limited by the inefficiency of energy transfer.
dynamic stability hypothesis
Long food chains are less stable than short chains.
light limitation
Depth to which light penetrates limits primary production.
species diversity
Variety of different kinds of organisms that make up a community.
quaternary consumer
Carnivore that eats tertiary consumers.
primary consumer
Herbivore.
biomanipulation
Technique for restoring eutrophic lakes that reduces populations of algae by manipulating higher-level consumers.
foundation species
Cause physical changes in environment that affect community structure.
producer
Autotroph.
mutualism
Interspecific interaction that benefits both species. (+/+)
relative abundance
The proportion of each species.
species-area curve
The larger the geographic area, the greater the number of species.
net primary production (NPP)
Energy used by primary producers for respiration.
ecological succession
Gradual recolonization of a disturbed area; species replaced by other species which are replaced by other species.
pioneer species
The first species that colonize new area, such as lichen and mosses.
evapotranspiration
Evaporation of water from soil plus transpiration from plants. Correlates with species richness.
actual evapotranspiration
Annual amount of water transpired by plants and evaporated from landscape.
detritus
Nonliving organic maters such as remains of dead organisms, feces, fallen leaves, dead wood.
limiting nutrient
Greater limiting factor than light in oceans and lakes.
keystone species
Not necessarily abundant, but exert a strong control on community structure due to a pivotal ecological role.
top-down model
Influence moves from top trophic levels to bottom. (V <-- H)
intermediate disturbance
Moderate levels of disturbance can create conditions that foster greater species diversity.
Müllerian mimicry
Two or more unpalatable species resemble each other.
bottom-up model
Unidirectional influence from lower to higher trophic levels. (V --> H)
primary production
Amount of light energy converted to chemical energy by autotrophs.
ectoparasites
Parasites that feed on external surface of host.
human disturbance
Reduces species diversity in all communities.
parasitoidism
Insects that lay eggs on or in living host; larvae feed on body of host, eventually killing it. (+/-)
endoparasites
Parasites that live within the body of their host.
commensalism
Interaction between species that benefits one but neither helps or harms the other. (+/0)
species richness
Total number of different species.
secondary consumer
Carnivore that eats herbivores.
nonequilibrium model
Communities are constantly changing after being buffeted by disturbances.
biomass
Total dry mass of all individuals in a population.
primary succession
Succession that begins in a virtually lifeless area.
tertiary consumer
Carnivore that eats carnivores.
facilitators
Foundation species have positive effects on other species.
trophic structure
Feeding relationships between organisms in a community.
Section 11
(50 cards)
peroxisome
A microbody containing enzymes that transfer hydrogen from various substrates to oxygen, producing and then degrading hydrogen peroxide.
production efficiency
The fraction of energy stored in food that was not used for cell respiration.
mitochondria
The organelles in which nutrients are converted to energy.
thylakoids
Membranous structures within a chloroplast that serve as the site for light harvesting in photosynthesis.
pyramids of numbers
Number of organisms at each trophic level.
vesicle
Small membrane-bound sac that functions in moving products into, out of, and within a cell.
Greenhouse Effect
Carbon dioxide and water vapor in atmosphere trap infrared radiation, re-reflecting it back toward earth.
biological augmentation
Uses organisms to add essential materials to degraded ecosystems.
Golgi apparatus
Stack of membranes in the cell that modifies, sorts, and packages proteins from the endoplasmic reticulum.
chromosomes
A threadlike, gene-carrying structure found in the nucleus. Consists of one very long DNA molecule and associated proteins.
smooth ER
Synthesis of lipids, phospholipids and steroid sex hormones-help detoxify drugs and poisons (liver cells).
Green World Hypothesis
Terrestrial herbivores consume relatively little plant biomass because they are held in check by predators, parasites and disease.
contractile vacuoles
A membranous sac that helps move excess water out of the cell.
turnover time
Standing crop biomass compared to production.
stroma
The fluid of the chloroplast surrounding the thylakoid membrane; involved in the synthesis of organic molecules from carbon dioxide and water.
diffusion
When a substance moves from an area of higher concentration to an area of lower concentration. Due to entropy.
cell wall
Strong layer around the cell membrane in plants, algae, and some bacteria.
bioremediation
Use of living organisms such as prokaryotes, fungi, or plants to detoxify polluted ecosystems.
eukaryotic cells
Contain a nucleus and other organelles that are bound by membranes.
biological magnification
Toxins become more concentrated in successive trophic levels.
critical load
The amount of added nutrient that can be absorbed by plants without damaging ecosystem.
cytoplasmic streaming
The motion of cytoplasm in a cell that results in a coordinated movement of the cell's contents.
cristae
Infoldings of the inner membrane of a mitochondrion that houses the electon transport chain and the enzyme catalyzing the synthesis of ATP.
pyramid of energy
90% of all energy is lost between trophic levels.
osmosis
The diffusion of water through a selectively permeable membrane.
cytoplasm
The region of the cell between the cell membrane and the nucleus.
chloroplasts
Organelles that capture the energy from sunlight and convert it into chemical energy in a process called photosynthesis.
10% rule
Only 10% of the total energy produced at each trophic level is available to the next level. The amount of energy passed up to the levels of the food pyramid reduces as you go up.
pyramids of biomass
Each on this pyramid tier represents standing crop.
chromatin
The readily stainable substance of a cell nucleus consisting of DNA and RNA and various proteins.
nuclear lamina
A netlike array of protein filaments lining the inner surface of the nuclear envelope; it helps maintain the shape of the nucleus.
threatened species
Species that is likely to become endangered.
nucleolus
Small, dense region within most nuclei in which the assembly of proteins begins.
lysosome
A cell organelle that contains digestive enzymes.
glycoprotein
A protein with one or more carbohydrates covalently attached to it.
endangered species
Species that is in danger of extinction throughout all or a significant portion of its range.
endomembrane system
A network of membranes inside and around a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles.
transport vesicles
Vesicles in transit from one part of the cell to another.
plasma membrane
The membrane at the boundary of every cell that acts as a selective barrier, thereby regulating the cell's chemical composition.
restoration ecology
Applies ecological principles in an effort to return degraded ecosystems to conditions as similar as possible to their natural state.
ozone layer
Protective layer in atmosphere that shields earth from UV radiation.
nuclear envelope
Double membrane perforated with pores that control the flow of materials in and out of the nucleus.
cytosol
The soluble portion of the cytoplasm, which includes molecules and small particles, such as ribosomes, but not the organelles covered with membranes.
trophic efficiency
Percentage of production transferred from one trophic level to the next.
conservation biology
Integrates ecology, physiology, molecular biology, genetics and evolutionary biology to conserve biological diversity.
secondary production
Amount of chemical energy in consumers' food that is converted to new biomass.
phagocytosis
Process in which extensions of cytoplasm surround and engulf large particles and take them into the cell.
rough ER
A network of interconnected membranous sacs in a eukaryotic cell's cytoplasm; covered with ribosomes that make membrane proteins and secretory proteins.
cytoskeleton
Network of protein filaments within some cells that helps the cell maintain its shape and is involved in many forms of cell movement.
organelles
Structures specialized to perform distinct processes within a cell.
Section 12
(50 cards)
cytolysis
This happens when a cell swells until pressure bursts it, resulting in cell death.
integral proteins
Integral proteins that span the membrane.
turgid
A cell with a cell wall that has a reasonable amount of pressure but is healthy.
selective permeability
A property of a plasma membrane that allows some substances to cross more easily than others.
ligand
Any molecule that bonds specifically to a receptor site of another molecule.
signal transduction
A series of molecular changes that converts a signal on a target cell's surface to a specific response inside the cell.
pressure potential
This measurement has a minimum value of 0 (when the solution is open to the environment); it increases as pressure increases.
electrochemical gradient
The combination of forces that acts on membrane potential.
pinocytosis
A type of endocytosis in which the cell "gulps" droplets of fluid into tiny vesicles.
isotonic
Describes solutions that have an equal concentration of total solutes.
crenation
This happens when a cell shrinks and shrivels; can result in cell death if severe.
flaccid
This happens when water moves, but the amount within the cell is constant; no pressure builds.
passive transport
Transport of a substance across a cell membrane by diffusion. No cell energy required.
turgor pressure
The pressure inside of a cell as a cell pushes itself against the cell wall.
peripheral proteins
The proteins of a membrane that are not embedded in the lipid bilayer; they are appendages loosely bound to the surface of the membrane.
enzymatic activity
A protein built into the membrane with active site exposed.
active transport
When a cell gets materials or excretes them by using its own energy, usually through ATP; going against a concentration gradient.
proton pump
An electrogenic pump that works largely with H+ ions.
plasmolysis
This happens when a cell shrinks inside its cell wall while the cell wall remains intact.
intercellular joining
The function of membrane proteins in which membrane proteins of adjacent cells hook together, as in gap junctions or tight junctions.
hypertonic
Describes a solution that has a greater concentration of total solute.
concentration gradient
A difference in the concentration of a substance across a distance.
membrane potential
The voltage of a plasma membrane.
dialysis
The diffusion of small solutes through a selectively permeable membrane.
receptor-mediated
A type of endocytosis in which the cell acquires bulk quantities of specific substances, even though they may not be very concentrated in the extracellular fluid.
endocytosis
Occurs when a cell takes in biological molecules and particulate matter by forming new vesicles from the plasma membrane.
transport protein
A membrane protein, specifically a transport protein, that has a hydrophilic channel that certain molecules or atomic ions use as a tunnel.
glycoproteins
Membrane carbohydrates that are covalently bonded to proteins.
hypotonic
Describes a solution that has a lesser concentration of total solute.
cotransport
The coupling of the "downhill" diffusion of one substance to the "uphill" transport of another against its own concentration gradient.
solute potential
This measurement has a maximum value of 0; it decreases as the concentration of a solute increases.
exocytosis
Occurs when a cell secretes certain biological molecules by the fusion of vesicles with the plasma membrane.
electrogenic pump
A transport protein that generates voltage across a membrane, causing a net separation in charge.
osmoregulation
The control of water balance.
water potential
The physical property predicting the direction in which water will flow, governed by solute concentration and applied pressure.
transport
An exchange of molecules (and their kinetic energy and momentum) across the boundary between adjacent layers of a fluid or across cell membranes.
phagocytosis
Process in which extensions of cytoplasm surround and engulf large particles and take them into the cell.
cell-cell recognition
The function of membrane proteins in which some glycoproteins serve as ID tags that are recognized by membrane proteins of other cells.
glycolipids
Membrane carbohydrates that are covalently bonded to lipids.
local regulators
These regulators influence cells in the vicinity of them.
gated channel
A protein channel in a cell membrane that opens or closes in response to a particular stimulus.
amphipathic
Molecules are said to be this when it has regions that are both hydrophilic and hydrophobic.
facilitated diffusion
Passive diffusion that is aided by transport proteins, but that does not require cellular energy.
tonicity
The ability of a solution to cause a cell to gain or lose water; depends partly on concentration of nonpenetrating solutes relative to inside of cell.
channel protein
A membrane protein, specifically a transport protein, that has a hydrophilic channel that certain molecules or atomic ions use as a tunnel.
transmembrane proteins
Integral proteins that span the membrane.
signal transduction pathway
The process by which a signal on a cell's surface is converted into a specific cellular response.
aquaporin
A membrane protein, specifically a transport protein, that facilitates the passage of water through channel proteins.
carrier protein
A membrane protein, specifically a transport protein, that holds onto molecules and changes their shapes in a way that shuttles them across the membrane.
fluid mosaic model
Structural model of the plasma membrane where molecules are free to move sideways within a lipid bilayer.
Section 13
(50 cards)
basal metabolic rate (BMR)
The metabolic rate of a nongrowing, resting, fasting, nonstressed endotherm.
abdominal cavity
Cavity housing intestines.
second messengers
Small, non-protein water soluble molecules or ions that send messages throughout the cells by diffusion.
chondrocytes
Cells that secrete cartilage.
blood
Connective tissue made of plasma, erythrocytes, leukocytes, and platelets.
tissues
Groups of cells with a common structure and function.
endothermic
Animals that are warmed mostly by heat generated by metabolism.
basement membrane
Cells at the base of an epithelial layer are attached to this.
fibroblasts
In connective tissue, cells that secrete the proteins of the fibers.
simple epithelium
Single layer of cells.
protein phosphatases
Enzymes that can rapidly remove phosphate groups from proteins.
squamous epithelium
Cells that are like floor tiles.
macrophages
Amoeboid cells that roam connective tissue and engulf foreign particles and debris of dead cells.
inositol triphosphate
Produced by cleavage of a certain kind of phospholipid in the plasma membrane.
collagenous fibers
Fibers made of collagen.
adipose tissue
Tissue that stores fat.
organs
Tissues are organized into:, group of tissues that work together to perform closely related functions.
metabolic rate
Amount of energy an animal uses in a unit of time; the sum of all the energy-requiring biochemical reactions.
hormones
Circulating chemical signals that are formed in specialized cells, travels in body fluids, and act on specific target cells.
fibrous connective tissue
Dense tissue, large number of collagen fibers organized into parallel bundles. Includes ligaments and tendons.
skeletal muscle
Muscle that is striated, multinucleated.
osteoblasts
Bone-forming cells.
ligaments
Join bones to bones at joints.
bioenergetics
Flow of energy through an animal. Limits its behavior, growth, reproduction.
physiology
Study of the functions an organism performs.
connective tissue
Tissue that functions mainly to bind and support other tissues.
columnar epithelium
Cells shaped like bricks standing on end.
mesenteries
Sheets of connective tissue in moist or fluid-filled body cavities.
cartilage
Made of collagenous fibers in matrix of chondroitin sulfate.
loose connective tissue
Tissue that binds epithelia to underlying tissues and holds organs in place. Contains collagenous, elastic, and recticular fibers.
bone
Mineralized connective tissue.
cubiodal epithelium
Dice-shaped cells.
mucous membrane
Membrane that secretes mucus that lubricates the surface of organs and keeps them moist.
epithelial tissue
Tissue that covers outside of the body and lines organs and cavities.
muscle tissue
Tissue made of cells capable of contracting.
glandualar epithelia
Tissue that absorbs or secretes chemical solutions.
exothermic
Animals that gain heat mostly from external sources.
reticular fibers
Fibers made of collagen fibers that are very thin and branched. Forma tightly woven fabric that joins connective tissue to adjacent tissues.
elastic fibers
Fibers made of elastin.
scaffolding proteins
A type of large relay protein to which several other relay proteins are simultaneously attached to increase the efficiency of signal transduction.
cardiac muscle
Muscle that is branched, striated, singe nucleated.
ligand
Any molecule that bonds specifically to a receptor site of another molecule.
tendons
Attach muscles to bones.
stratified epithelium
Multiples tiers of cells.
adenylyl cyclase
Converts ATP to cyclic AMP in response to an extracellular signal.
anatomy
Study of the structure of an organism.
thoracic cavity
cavity housing lungs and heart
nervous tissue
Tissue that senses stimuli and transmits signals.
protein kinase
The enzyme that transfers phosphate groups from ATP to protein.
smooth muscle
Muscle that is not striated, is single nucleated.
Section 14
(50 cards)
cellular respiration
When oxygen is consumed as a reactant along with the organic fuel.
conformer
An animal that allows its internal condition to vary with certain external changes.
thermoregulation
Process of maintaining an internal temperature within a tolerable range.
heat-shock proteins
Proteins that help maintain integrity of other proteins that would normally be denatured in extreme heat.
enzyme
A catalytic protein.
active site
A pocket or groove on the surface of the enzyme.
kinetic energy
Energy associated with relative motion of objects.
induced fit
Brings chemical groups of the active site into positions that enhance their ability to catalyze the chemical reaction.
competitive inhibitors
Reduce the productivity of enzymes by blocking substrates from entering active sites.
torpor
Physiological state in which activity is low and metabolism decreases.
metabolic pathway
Begins with a specific molecule, which is then altered in a series of defined steps, resulting in a certain product.
vasoconstriction
Reduces blood flow and heat transfer by decreasing the diameter of superficial blood vessels.
entropy
A measure of disorder or randomness.
catabolic pathways
Metabolic pathways that release energy by breaking down complex molecules into simpler compounds.
potential energy
Occurs when an object is not moving, but may still posses energy.
allosteric regulation
When a protein's function at one site is affected by the binding of a regulatory molecule to a separate site.
phosphorylation
The metabolic process of introducing a phosphate group into an organic molecule.
standard metabolic rate (SMR)
The metabolic rate of a resting, fasting, nonstressed ectotherm.
thermal energy
Kinetic energy associated with the random movement of molecules or atoms.
vasodialation
Increases in the diameter of superficial blood vessels; cools the body.
homeostasis
"Steady state" or "constant internal milieu".
estivation
Summer torpor. Enables animals to survive long periods of high temperatures and scarce water supplies.
brown fat
Tissue in neck and between shoulders of some mammals that is specialized for rapid heat production.
interstitial fluid
Watery, internal environment of vertebrates.
acclimatization
Adjusting to a new range of environmental temperatures.
countercurrent heat exchanger
In ectotherms, a circulatory adaptation that is an arrangement of blood vessels that warm or cool the blood.
fermentation
A partial degradation of sugars that occur without the use of oxygen.
catalyst
A chemical agent that speeds up a reaction without being consumed by the reaction.
endergonic reaction
Reaction that absorbs free energy from its surroundings.
coenzyme
If the cofactor is an organic molecule.
energy coupling
The use of an exergonic process to drive an endergonic one.
positive feedback
A type of regulation that responds to a change in conditions by initiating responses that will amplify the change. Takes organism away from a steady state.
nonshivering thermogenesis (NST)
When hormones cause mitochondria to produce heat instead of ATP in some mammals.
hibernation
Long-term torpor that is an adaptation to winter cold and food scarcity.
first law of thermodynamics
Energy can be transferred and transformed, but it cannot be created or destroyed.
noncompetitive inhibitors
Impede enzymatic reactions by binding to another part of the enzyme (other than the active site).
anabolic pathways
Metabolic pathways that consume energy to build complicated molecules from simpler ones.
activation energy
The amount of energy needed to push the reactants over an energy barrier.
enzyme-substrate complex
When an enzyme binds to its substrate, it forms:
exergonic reaction
Reaction that proceeds with a net release of free energy.
negative feedback
A type of regulation that responds to a change in conditions by initiating responses that will counteract the change. Maintains a steady state.
cofactor
Non-protein helpers that may be bound tightly to the enzyme as a permanent resident, or may bind loosely and reversibly along with the substrate.
feedback inhibition
A metabolic pathway is switched off by the inhibitory binding of its end product to an enzyme that acts early in the pathway.
ATP (adenosine triphosphate)
Composed of a sugar ribose, nitrogenous base adenine, and a chain of three phosphate groups bonded to it.
cooperativity
It amplifies the response of enzymes to substrates.
regulator
An animal that uses internal control mechanisms to moderate internal change in the face of external fluctuation.
daily torpor
in small mammals and birds, daily lowering of metabolism that allows them to survive on stored energy
bioenergenetics
The study of how organisms manage their energy resources.
second law of thermodynamics
Every energy transfer or transformation increases the entropy of the universe.
free energy
Measures the portion of a system's energy that can perform work when temperature and pressure are uniform throughout the system, as in a living cell.
Section 15
(50 cards)
acetyl-CoA
Is formed when pyruvate first enters into the mitochondria via active transport.
epitope
Small, accessible portion of an antigen that can be recognized.
humoral immune response
The branch of acquired immunity that involves the activation of B cells and that leads to the production of antibodies, which defend against bacteria and viruses in body fluids.
immunoglobulins
Secreted antibodies.
ATP synthase
The enzyme that make ATP from ADPand inorganic phosphate.
proton-motive force
Emphasizes the capactiy of the gradient to preform work.
thymus
Gland in the thoracic cavity above the heart where T lymphocytes mature.
oxidizing agent
B oxidizes A by removing A's electrons.
cell-mediated immune response
The branch of acquired immunity that involves the activation of cytotoxic T cells, which defend against infected cells.
neutrophils
Most abundant white blood cell., The most abundant type of white blood cell. Phagocytic and tend to self-destruct as they destroy foreign invaders, limiting their life span to a few days.
histamine
Chemical stored in mast cells that triggers dilation and increased permeability of capillaries.
citric acid cycle
Completes the breakdown of glucose by oxidizing a derivative of pyruvate to carbon dioxide.
anaerobic
Occurs by fermentation, which generate ATP solely by substrate-level phosphorylation.
memory cells
General term for lymphocytes that are responsible for immunological memory and protective immunity.
antigen
Any foreign molecule that is specifically recognized by lymphocytes and elicits an immune response.
electron transport chain
Breaks the fall of electrons to oxygen in several energy-releasing steps.
antigen presentation
The process by which an MHC molecule binds to a fragment of an intracellular protein antigen and carries it to the cell surface, where it is displayed and can be recognized by a T cell.
substrate-level phosphorylation
When an enzyme transfers a phosphate group from a substrate molecule.
secondary immune response
Immune response after the body has already been exposed to a specific antigen. Response is faster, of greater magnitude, and more prolonged.
B lymphocytes (B cells)
Lymphocyte that matures in the bone marrow and secretes antibodies.
active immunity
A form of acquired immunity in which the body produces its own antibodies against disease-causing antigens.
passive immunity
Immunity conferred by transferring antibodies from an individual who is immune to a pathogen to another individual.
oxidation
Loss of electrons.
primary immune response
Immune response the first time the body is exposed to a particular antigen. Does not peak until 10-17 days after exposure.
acquired immunity
Immunity that is present only after exposure and is highly specific.
Acquired Immunodeficiency Syndrome (AIDS)
The most advanced, and fatal, stage of an HIV infection.
graft versus host reaction
When lymphocytes in donated bone marrow react against the recipient.
lymphocytes
White blood cells.
complement system
A group of about 30 blood proteins that may amplify the inflammatory response, enhance phagocytosis, or directly lyse extracellular pathogens.
redox reactions
When there is a transfer of one or more electrons from one reactant to another.
helper T cells
Activate macrophages, B cells and T cells.
interferon
Protein produced by cells in response to being infected by a virus; helps other cells resist the virus.
glycolosis
Breaking glucose into two molecules of a compound called pyruvate.
anaphylactic shock
A severe reaction that occurs when an allergen is introduced to the bloodstream of an allergic individual. Characterized by bronchoconstriction, labored breathing, widespread vasodilation, circulatory shock, and sometimes sudden death.
autoimmune diseases
Diseases caused when the immune system loses tolerance for self and turns against certain molecules in the body.
antibodies
Protein that is produced by lymphocytes and that attaches to a specific antigen.
lactic acid fermetation
When pyruvate is reduced directly by NADH to form lactic as am end product, with no release of carbon dioxide.
innate immunity
Immunity that is present before exposure and effective from birth. Responds to a broad range of pathogens.
reduction
Gain of electrons.
natural killer (NK) cells
These cells kill cancer cells and cells infected with viruses. They bind to their targets and deliver a lethal burst of chemicals to produce holes in the target cell's membrane leading to its destruction.
inflammtory response
Innate response with the purpose of containing a site of damage, localizing the response, eliminating the invader and restore tissue function.
T lymphocytes (T cells)
Lymphocyte that matures in the thymus and acts directly against antigens in cell-mediated immune responses.
chemiosmosis
When energy is stored in the form of a hydrogen ion gradient across a membrane which is used to drive cellular work.
immunization
The deliberate exposure of a pathogen to produce memory cells.
Rh factor
Refers to the presence or absence of the Rh antigen on red blood cells.
facultative anaerobes
Can make enough ATP to survive using using fermentation or respiration.
oxidative phosphorylation
When energy is released at each step of the chain is stored in a form the mitochondrion can use to make ATP.
reducing agent
A reduces B, which accepts the donated electrons.
alcohol fermentation
When pyruvate is converted to ethanol in 2 steps.
B cell receptor
The antigen receptor on B cells: a Y-Shaped, membrane-bound molecule consisting of two identical heavy chains and two identical light chains linked by disulfide bridges and containing two antigen-binding sites.
Section 16
(50 cards)
Central Nervous System (CNS)
Includes the brain and spinal cord.
pattern formation
The development of a spatial organization of tissues and organs.
presynaptic cell
The transmitting neuron in a synapse.
fate maps
A labor-intensive study to produce useful territorial diargams of embryonic development.
action potential
A neural impulse; a brief electrical charge that travels down an axon.
serotonin
A neurotransmitter that affects hunger,sleep, arousal, and mood.
glucagon
The antagonist of insulin that helps increase blood sugar. It stimulates the liver to break down glycogen into glucose.
dopamine
Important neurotransmitter in the CNS that acts on the sympathetic nervous system.
motor neurons
Neurons that carry outgoing information from the central nervous system to the muscles and glands.
oligodendrocytes
Type of glial cell in the CNS that wrap axons in a myelin sheath.
major histocompatibility compex (MHC)
Binds to a fragment of an antigen within a cell and presents it on the surface of the membrane.
nodes of Ranvier
Gaps in the myelin sheath to which voltage-gated sodium channels are confined.
endocrine signaling
Specialized cells release hormone molecules into vessels of the circulatory system, by which they travel to target cells in other parts of the body.
synaptic vesicles
Membrane-bounded compartments in which synthesized neurotransmitters are kept.
cell body
Contains most of a neuron's organelles and its nucleus.
dendrites
Highly branched extensions that receive signals from other neurons.
cytotoxic T cells or "killer T cells"
T cells that directly attack infecting organisms; these cells attack antigen labeled foreign or host tissue.
postsynaptic cell
The neuron, muscle, or gland cell that receives the signal from a neuron.
insulin
Hormone produced by the pancreas that helps to decrease blood sugar.
Schwann cells
Type of glia in the PNS, Supporting cells of the peripheral nervous system responsible for the formation of myelin.
depolarization
The process during the action potential when sodium is rushing into the cell causing the interior to become more positive.
prostaglandins
Modified fatty acids that are produced by a wide range of cells.
nitric oxide (NO)
Local regulator that regulates blood oxygen levels, A gas produced by many types of cells that functions as a local regulator and as a neurotransmitter.
threshold potential
The minimum membrane potential that must be reached in order for an action potential to be generated.
edocrine glands
Glands that secrete chemicals called hormones directly into the bloodstream.
paracrine signaling
Signal released from a cell has an effect on neighboring cells.
growth factors
Factors that stimulate the cell to divide.
epinephrine
Neurotransmitter secreted by the adrenal medulla in response to stress. Also known as adrenaline.
T cell receptor
Antigen receptors on a T cell. Unlike antibodies, T cell receptors are never produced in a secreted form.
endocrine system
The system of glands that produce endocrine secretions that help to control bodily metabolic activity.
membrane potential
The voltage across a cell's plasma membrane.
morphogenesis
The process by which an organism takes shape and the differentiated cells occupy their appropriate locations.
positional information
The molecular cues that control pattern formation.
acetylcholine
Common vertebrate neurotransmitter, especially in neuromuscular junctions.
neurotransmitters
Chemical messengers that cross the synaptic gaps between neurons.
hormone
The secretion of an endocrine gland that is transmitted by the blood to the tissue on which it has a specific effect.
Peripheral Nervous System (PNS)
The sensory and motor neurons that connect the CNS to the rest of the body.
synaptic cleft
The narrow gap that separates the presynaptic neuron from the postsynaptic cell.
myelin sheath
A layer of electrical insulation that surrounds the axon.
resting potential
The membrane potential of a neuron that is at rest.
axon hillock
Cone shaped region of an axon where it joins the cell body.
synaptic terminal
A bulb at the end of an axon in which neurotransmitter molecules are stored and released.
norepinephrine
A precursor of epinephrine that is secreted by the adrenal medulla and also released at synapses.
axon
Long nerve fiber that conducts away from the cell body of the neuron.
voltage-gated ion channels
Channels that open or close in response to a change in the membrane potential.
cell differentiation
Cell specialization in structure and function.
sensory neurons
Neurons that carry incoming information from the sense receptors to the central nervous system.
cytokines
Chemicals released by the immune system communicate with the brain.
neurosecretory cells
Neurons that secrete neurohormone rather than neurotransmitter.
synapse
The junction between two neurons or between a neuron and a muscle.
Section 17
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imprinting
Includes both learning and innate components, generally irreversible.
enteric division
One of three divisions of the autonomic nervous system; consists of networks of neurons in the digestive tract, pancreas, and gallbladder.
midbrain
Region between the hindbrain and the forebrain; it is important for hearing and sight.
neuron
Structural and functional unit of nervous system.
proximate questions
Address environmental stimuli, genetic, physiological, and anatomical causes of a behavior.
cerebral cortex
Interconnected neural cells that covers the cerebral hemispheres; the body's ultimate control and information-processing center.
operant conditioning
Learning based on the consequences of responding.
cerebral hemispheres
The right and left halves of the cerebrum.
cerebrum
Largest part of the brain; responsible for voluntary muscular activity, vision, speech, taste, hearing, thought, and memory.
fixed action patterns (FAP)
A sequence of unlearned behavioral acts that is unchangeable and usually carried to completion.
recticular formation
Registers and controls activity level, increases excitement, and helps generate sleep.
migration
Relatively long-distance movement of individuals, usually on a seasonal basis.
glutamate
The most common neurotransmitter in the brain. Excitatory.
parasympathetic division
A branch of the autonomic nervous system that maintains normal body functions; it calms the body ever conserves energy.
classical conditioning
An arbitrary stimulus is associated with an award or punishment.
ethology
The scientific study of how animals behave, particularly in natural environments.
cognitive maps
An internal representation of the spatial relationships between objects in an animal's surroundings.
thalamus
Major input center for sensory information going to the cerebrum and the main output center for motor information leaving the cerebrum.
cerebellum
The "little brain" attached to the rear of the brainstem; it helps coordinate voluntary movement and balance.
behavior
The way an organism reacts to changes in its internal condition or external environment.
astrocytes
Provide structural and metabolic support for neurons.
medulla oblongata
Contains centers that control several visceral functions, including breathing, heart and blood vessel activity, swallowing, vomiting, and digestion.
hindbrain
The posterior portion of the brain including cerebellum and brainstem.
GABA
An inhibitory neurotransmitter in the brain.
ultimate questions
Address evolutionary significance of a behavior.
sympathetic division
The part of the autonomic nervous system that arouses the body to deal with perceived threats.
taxis
Automatic, oriented movement toward or away from some stimuli.
brainstem
The oldest part and central core of the brain, responsible for automatic survival functions.
biological clock
An innate mechanism in living organisms that controls the periodicity of many physiological functions.
communication
Signals among animals that include sounds, odors, visual displays, and touches that produce responses.
cognition
The ability of an animal's nervous system to perceive, store, process, and use information gathered by sensory receptors.
sensitive period
A limited phase in an animal's development that is the only time when certain behaviors can be learned.
white matter
Whitish nervous tissue of the CNS consisting of neurons and their myelin sheaths.
innate behavior
A behavior that is developmentally fixed.
habituation
A loss of responsiveness to stimuli that convey little or no information.
forebrain
The largest and most complicated region of the brain, including the thalamus, hypothalamus, limbic system, and cerebrum.
associative learning
The ability of animals to associate one feature with another.
endorphins
Natural analgesics that decrease pain perception.
grey matter
The portions of the central nervous system that are abundant in cell bodies of neurons rather than axons. Unmyelinated.
sign stimulus
External sensory stimulus that triggers a fixed action pattern.
autonomic nervous system
The part of the nervous system of vertebrates that controls involuntary actions of the smooth muscles and heart and glands.
glial cells
Cells in the nervous system that support, nourish, and protect neurons.
signal
A behavior that causes change in another's behavior.
effector cells
Muscle cells or gland cells that carry out the body's response to stimuli.
ganglion
A cluster of nerve cell bodies, often of similar function, located in the PNS.
spatial learning
The modification of behavior based on experience with the spatial structure of the environment.
corpus callosum
Nerves that enable communication between the right and left cerebral hemispheres.
kinesis
A simple change in activity or turning rate in response to a stimuli.
learning
The modification of behavior based on specific experiences.
circadian rhythms
The 24-hour biological cycles found in humans and many other species.
Section 18
(50 cards)
binary fission
A form of asexual reproduction in single-celled organisms by which one cell divides into two cells of the same size.
centrosome
A structure in animal cells containing centrioles from which the spindle fibers develop.
culture
A system of information transfer through influential social learning or teaching.
inclusive fitness
The total effect an individual has on proliferating its genes by producing its own offspring and by providing aid that enables other close relatives to increase the production of their offspring.
monogamous
One male mating with one female.
growth factors
Regulatory proteins that ensure that the events of cell division occur in the proper sequence and at the correct rate.
chromatin
The readily stainable substance of a cell nucleus consisting of DNA and RNA and various proteins.
metaphase plate
Plane midway between the two poles of the cell where chromosomes line up during metaphase.
asters
Microtubules and fibers that radiate out from the centrioles.
polygyny
One male, several females.
allele
One of the alternative forms of a gene that governs a characteristic, such as hair color.
foraging
Behavior associated with recognizing, searching for, capturing, and consuming food.
restriction point
A point of no return in the cell cycle; once this point passes, a cell is committed to a full round of the cell cycle.
coefficient of relatedness
Probability that if two individuals share common parent or ancestor, a particular gene present in one will be present in other.
G2 phase
The second growth phase of the cell cycle, consisting of the portion of interphase after DNA synthesis occurs.
mitotic spindle
An assemblage of microtubules and associated proteins that is involved in the movements of chromosomes during mitosis.
G1 phase
The first gap, or growth phase, of the cell cycle, consisting of the portion of interphase before DNA synthesis begins.
Hamilton's rule
when C < r x B C = cost to the altruistic party r = genetic relatedness B = fitness benefit to recipient of altuism
polyandry
One female, several males.
chromosomes
Threadlike structures made of DNA molecules that contain the genes.
kinetochore microtubules
Connects the centrosome with the kinetochore in the centromere region of the chromosome.
cleavage furrow
The first sign of cleavage in an animal cell; a shallow groove in the cell surface near the old metaphase plate.
cell division
The process in reproduction and growth by which a cell divides to form daughter cells.
centromere
The region of the chromosome that holds the two sister chromatids together during mitosis.
Cdk
Complex of cyclin and kinase.
cleavage
The process of cytokinesis in animal cells, characterized by pinching of the plasma membrane; specifically.
agonistic behavior
Competition that determines who wins a prize, such as food or mates.
optimal foraging theory
Views foraging behavior as a compromise between benefits of nutrition and costs of obtaining food.
cell plate
A double membrane across the midline of a dividing plant cell, between which the new cell wall forms during cytokinesis.
density dependent inhibition
The arrest of cell division that occurs when cells grown in a laboratory dish touch one another.
social learning
Learning through observing others.
MPF
A cyclin-Cdk complex that causes the cell to move from interphase into mitosis.
interphase
Cell grows, performs its normal functions, and prepares for division; consists of G1, S, and G2 phases.
cancer
Any malignant growth or tumor caused by abnormal and uncontrolled cell division.
genome
The ordering of genes in a haploid set of chromosomes of a particular organism.
cell cycle
Series of events that cells go through as they grow and divide.
M phase
Mitosis and cytokinesis.
cytokinesis
Division of the cytoplasm to form two separate daughter cells.
polygamous
An individual of one sex mating with several of the other.
centriole
In animal cells, a cytoplasmic organelle that organizes the mitotic spindle fibers during cell reproductions.
game theory
Evaluates alternate strategies when outcome depends not only on each individual's strategy but also that of others.
mitosis
Cell division in which the nucleus divides into nuclei containing the same number of chromosomes.
kinetochore
A specialized region on the centromere that links each sister chromatid to the mitotic spindle.
altruism
Behavior that benefits another without benefiting oneself.
kin selection
Natural selection that favors altruistic behaviors by enhancing reproductive success of relatives.
S phase
The synthesis phase of the cell cycle; the portion of interphase during which DNA is replicated.
mate choice copying
Individuals in a population copy mate choice of others.
somatic cell
Any of the cells of a plant or animal except the reproductive cells.
sister chromatids
Identical copies of a chromosome; full sets of these are created during the S subphase of interphase.
promiscuous
No strong pair bonds or lasting relationships.
Section 19
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diploid cell
Has two sets of chromosomes.
multiplication rule
To determine the probability, we multiply the probability of one event by the probability of another.
independent assortment
The random distribution of the pairs of genes on different chromosomes to the gametes.
dominant allele
An allele whose trait always shows up in the organism when the allele is present.
recombinant chromosomes
Chromosomes that carry genes from each parent.
addition rule
Considering mutually exclusive events, the probability of both occurring is the sum of the probabilities of each event.
nonsister chromatids
Different chromatids (maternal and paternal) of the same chromosome.
F1 Generation
The hybrid offspring of true-breeding parents.
life cycle
All of the events in the growth and development of an organism until the organism reaches sexual maturity.
variation
Is demonstrated by the differences in appearance that offspring show from parents and siblings.
autosomes
Chromosomes that are not directly involved in determining the sex of an individual.
complete dominance
When the phenotypes of the heterozygote and dominant homozygote are indistinguishable.
zygote
Fertilized egg. Carries one set of chromosomes from each parent.
Punnett square
A diagram for predicting the allele composition of offspring from a cross between individuals of known genetic makeup.
fertilization
Union of gametes.
haploid
One set of chromosomes.
sporophyte
Diploid, or spore-producing, phase of an organism. Makes haploid spores by meiosis.
trait
Each variant of a character.
chiasmata
X-shaped regions where crossing over occurred.
alteration of generations
The alteration of two or more different forms in the life cycle of a plant or animal.
true-breeding
Organisms that, when reproducing, create offspring of all the same variety.
sex chromosomes
X and Y chromosomes.
genotype
An organism's genetic makeup.
homologous chromosomes
Pair of chromosomes that are the same size, same appearance and same genes.
locus
The specific site of a particular gene on its chromosome.
clone
An identical genetically individual of the parent
The Law of Segregation
Two alleles separate during gamete formation and end up in different gametes because they are on on homologous chromosomes.
character
A heritable feature that varies among individuals.
testcross
The result of breeding a recessive homozygote with an organism of dominant phenotype but unknown genotype.
homozygous
An organism having a pair of identical alleles for a character, either dominant or recessive.
monohybrids
Parents that are heterozygous for one character.
codominance
When which the phenotypes of both alleles are exhibited in the heterozygote.
asexual reproduction
One parent produces a genetically identical offspring by mitosis.
dihybrids
Parents that are heterozygous for two characters.
P generation
The name for the true-breeding parents.
crossing over
Nonsister chromatids exchanging DNA segments.
phenotype
An organism's traits.
F2 Generation
After the self-pollenization of the F1 generation, this is produced.
gametes
A haploid cell such as an egg or sperm that unite during sexual reproduction to produce a diploid zygote.
synapsis
Homologous chromosomes pair up, aligned gene by gene.
hybridization
The crossing of two true-breeding parents.
genes
Units of heredity made up of DNA.
heredity
Transmission of traits from one generation to the next.
genetics
Scientific study of heredity and variation.
tetrad
A pair of chromosomes form tetrads made up of four chromatids.
gametophyte
The stage in the life cycle of a plant in which the plant produces gametes, or sex cells.
recessive allele
An allele that is masked when a dominant allele is present
spores
Produced by meiosis. Grow into haploid organisms by mitosis.
karyotype
Photograph of chromosomes grouped in order and in pairs.
sexual reproduction
When two parents give unique combination of genes to offspring.
Section 20
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polygenic inheritance
An additive effect of two or more genes on a single phenotypic character.
origins of replication
Site where the replication of a DNA molecule begins, consisting of a specific sequence of nucleotides.
Downs Syndrome
A congenital disorder caused by having an extra Chromosome 21.
XO system
A sex determination system in some insects in which O stands for the absence of a sex chromosome. Females are XX, Males are XO. Males produce two classes of sperm: X sperm and sperm with no chromosome. The sperm determines the sex of the offspring.
replication fork
A Y-shaped region on a replicating DNA molecule where new strands are growing.
nondisjunction
Error in meiosis in which homologous chromosomes fail to separate.
DNA polymerase
An enzyme that catalyzes the formation of the DNA molecule.
hemophilia
An X-linked recessive disorder in which blood fails to clot properly, leading to excessive bleeding if injured.
deletion
A change to a chromosome in which a fragment of the chromosome is removed.
trisomic
A chromosomal condition in which a particular cell has an extra copy of one chromosome, instead of the normal two.
helicase
An enzyme that untwists the double helix at the replication forks, separating the two parental strands and making them available as template strands.
aminocentesis
Prenatal diagnostic technique that involves inserting a needle to obtain a sample of amniotic fluid that surrounds the fetus.
haplo diploid system
A sex determination system in most species of bees and ants in which there are no sex chromosomes. Females develop from fertilized eggs (diploid) and males develop from unfertilized eggs (haploid).
chorionic villus sampling (CVS)
Prenatal diagnostic technique that involves taking a sample of tissue from the chorion.
genomic imprinting
Variation in phenotype depending on whether an allele is inherited from the male or female parent.
lagging strand
A discontinuously synthesized DNA strand that elongates by means of Okazaki fragments, each synthesized in a 5' to 3' direction away from the replication fork.
Huntington's disease
Genetic disorder that causes progressive deterioration of brain cells. caused by a dominant allele. symptoms do not appear until about the age of 30.
X linked genes
Genes found on the X chromosome.
crossing over
Process in which homologous chromosomes exchange portions of their chromatids during meiosis.
recombinant types
Offspring who have inherited new combinations of genes and have phenotypes that don't match either parental phenotypes.
quantitative characters
Characters that vary in the population along a continuum (in gradations).
monosomic
A chromosomal condition in which a particular cell has only one copy of a chromosome, instead of the normal two.
XY system
A sex determination system in which females have two of the same kind of sex chromosome and males have two different ones.
genetic recombination
The regrouping of genes in an offspring that results in a genetic makeup that is different from that of the parents.
transformation
A change in genotype and phenotype due to the assimilation of external DNA by a cell.
genetic map
An ordered list of the genetic loci along a particular chromosome.
single-strand binding protein (SSB)
Binds to and stabilizes single-stranded DNA until it can be used as a template.
sex linked genes
Genes located on the sex chromosomes.
chromosome theory of inheritance
According to this theory, genes are carried from parents to their offspring on chromosomes.
leading strand
The new continuous complementary DNA strand synthesized along the template strand in the mandatory 5' to 3' direction.
cystic fibrosis
A genetic disorder that is present at birth and affects both the respiratory and digestive systems.
cytogenetic maps
A chart of a chromosome that locates genes with respect to chromosomal features distinguishable in a microscope.
barr body
A dense body formed from a deactivated X chromosome.
sickle-cell disease
Genetic disorder in which red blood cells have abnormal hemoglobin molecules and take on an abnormal shape.
translocation
Change to a chromosome in which a fragment of one chromosome attaches to a nonhomologous chromosome.
map units
A measurement of the distance between genes; one map unit is equivalent to a 1 percent recombination frequency.
semiconservative model
Type of DNA replication in which the replicated double helix consists of one old strand, derived from the old molecule, and one newly made strand.
pedigree
A diagram that shows the occurrence of a genetic trait in several generations of a family.
linkage map
A genetic map based on recombination frequencies.
Tay-Sachs disease
A human genetic disease caused by a recessive allele that leads to the accumulation of certain lipids in the brain. Seizures, blindness, and degeneration of motor and mental performance usually become manifest a few months after birth.
linked genes
Genes located on the same chromosome that tend to be inherited together in genetic crosses.
parental types
Offspring with a phenotype that matches one of the parental phenotypes.
ZW system
A sex determination system in fish, butterflies, birds where males are ZZ and Females are ZW. The egg determines the sex of the offspring.
bacteriophages
A virus that infects bacteria; also called a phage.
Duchenne muscular dystrophy
A human genetic disease caused by a sex-linked recessive allele; characterized by progressive weakening and a loss of muscle tissue.
inversion
A type of mutation in which the order of the genes in a section of a chromosome is reversed.
aneuploidy
Abnormal number of chromosomes.
incomplete dominance
Creates a blended phenotype; one allele is not completely dominant over the other.
primase
An enzyme that joins RNA nucleotides to make the primer using the parental DNA strand as a template.
Okazaki fragments
Small fragments of DNA produced on the lagging strand during DNA replication, joined later by DNA ligase to form a complete strand.
Section 21
(50 cards)
signal-recognition particle
A protein-RNA complex that recognizes a signal peptide as it emerges from the ribosome.
reading frame
Reading mRNA nucleotides in the correct groupings.
Watson and Crick
Developed the double helix model of DNA.
transfer RNA (tRNA)
Interpreter of a series of codons along a mRNA molecule.
McCarty, Avery, & MacLeod
Confirmed that the transforming agent in Griffith's experiment was DNA.
Erwin Chargaff
Discovered that DNA composition varies, but the amount of adenine is always the same as thymine and the amount of cytosine is always the same as guanine.
triplet code
Three-nucleotide long set that specifies a specific amino acid for a polypeptide chain.
exons
Coding segments of eukaryotic DNA.
one gene-one polypeptide hypothesis
there is one gene that codes for one polypeptide
RNA polymerase
Enzyme that links together the growing chain of ribonucleotides during transcription.
messenger RNA (mRNA)
Carries genetic message from the DNA to he protein-synthesizing machinery of the cell.
RNA processing
The modification of mRNA before it leaves the nucleus that is unique to eukaryotes.
splicosome
Different particles that recognize splice sites are compiled in a large assembly. A complex of RNA and protein subunits. Removes introns from a transcribed pre-RNA segments.
domains
Discrete structural and functional regions of proteins.
5' cap
The 5' end of a pre-mRNA molecule modified by the addition of a cap of guanine nucleotide.
codons
mRNA base triplets.
ribosomal A site
Site that holds the tRNA carrying the next amino acid to be added to the chain.
Meselson & Stahl
Determined that DNA replication is semiconservative.
promoter
A specific nucleotide sequence in DNA that binds RNA polymerase and indicates where to start transcribing mRNA.
introns
Noncoding segments of nucleic acid that lie between coding sequences.
template strand
The DNA strand that provides the template for ordering the sequence of nucleotides in an mRNA transcript.
polyribosomes
Strings of ribosomes that work together to translate a RNA message.
mutations
Random errors in gene replication that lead to a change in the sequence of nucleotides. The source of all genetic diversity.
transcription factors
Collection of proteins that mediate the binding of RNA polymerase and the initiation of transcription.
nuclease
A DNA cutting enzyme that excises damaged DNA.
telomeres
Repeated DNA sequences at the ends of eukaryotic chromosomes.
TATA box
A promoter DNA sequence crucial in forming the transcription initiation complex.
RNA splicing
Process by which the introns are removed from RNA transcripts and the remaining exons are joined together.
primary transcript
The initial mRNA transcript that is transcribed from a protein coding gene. Also called pre-mRNA.
telomerase
An enzyme that catalyzes the lengthening of telomeres in eukaryotic germ cells.
point mutations
chemical changes in just one base pair of a gene
transcription
Synthesis of an RNA molecule from a DNA template.
missense mutations
Most common type of mutation, a base pair mutation in which the new codon makes sense in that it still codes for an amino acid.
Frederick Griffith
Discovered transformation during an experiment that involved injecting mice with smooth S cells, rough R cells, heat-killed S cells, and heat-killed S cells with living R cells.
transcription initiation complex
The assembly of transcription factors and RNA polymerase.
translation
The synthesis of a polypeptide, which occurs under the direction of mRNA.
ribozymes
RNA molecules that function as enzymes.
nonsense mutations
A mutation that changes an amino acid codon to one of three stop codons, resulting in a shorter and usually nonfunctional protein.
ribosomes
Complex particles that facilitate the orderly linking of amino acids into polypeptide chains.
wobble
Flexibility in the base-pairing rules in which the nucleotide at the 5' end of a tRNA anticodon can form hydrogen bonds with more than one kind of base in the third position of a codon.
Hersey-Chase Experiment
Devised an experiment that showed that only the DNA of T2 phages enters a bacterial cell during infection.
ribosomal P site
Site that holds tRNA carrying the growing polypeptide chain.
Ribosomal E site
Site where discharged tRNAs leave the ribosome.
poly-A tail
Modified end of the 3' end of an mRNA molecule consisting of the addition of some 50 to 250 adenine nucleotides.
one gene-one polypeptide hypothesis
The premise that a gene is a segment of DNA that codes for one polypeptide.
anticodon
Specialized base triplet at one end of a tRNA molecule that recognizes a particular complementary codon on an mRNA molecule.
alternative RNA splicing
Genes giving rise to two or more different polypeptides depending upon which segments are treated as exons.
terminator
In prokaryotes, a special sequence of nucleotides in DNA that marks the end of a gene.
ribosomal RNA (rRNA)
RNA molecules that construct ribosomal subunits.
signal peptide
A stretch of amino acids on a polypeptide that targets the protein to a specific destination in a eukaryotic cell.
Section 22
(50 cards)
reverse transcriptase
An enzyme encoded by some certain viruses (retroviruses) that uses RNA as a template for DNA synthesis.
prophage
A phage genome that has been inserted into a specific site on the bacterial chromosome.
bacteriophage
A virus that infects bacteria; also called a phage.
insertion sequence
The simplest kind of transposable element, consisting of inverted repeats of DNA flanking a gene for transposase, the enzyme that catalyzes transposition.
vaccine
A harmless variant or derivative of a pathogen that stimulates a host's immune system to mount defenses against the pathogen.
repressor
A protein that suppresses the transcription of a gene.
lytic cycle
A type of viral (phage) replication cycle resulting in the release of new phages by lysis (and death) of the host cell.
R plasmid
A bacterial plasmid carrying genes that confer resistance to certain antibiotics.
F plasmid
The plasmid form of the F factor.
proteasomes
A giant protein complex that recognizes and destroys proteins tagged for elimination by the small protein ubiquitin.
nucleoid
A dense region of DNA in a prokaryotic cell.
gene cloning
The production of multiple copies of a gene.
provirus
Viral DNA that inserts into a host genome.
regulatory gene
A gene that codes for a protein, such as a repressor, that controls the transcription of another gene or group of genes.
F factor
A piece of DNA that confers the ability form a sex pili.
temperate phage
A phage that is capable of reproducing by either the lytic or lysogenic cycle.
transposable genetic element
A segment of DNA that can move within the genome of a cell by means of a DNA or RNA intermediate; also called a transposable element.
operon
A unit of genetic function common in bacteria and phages, consisting of coordinately regulated clusters of genes with related functions.
plasmid
A small ring of DNA that carries accessory genes separate from those of a bacterial chromosome; also found in some eukaryotes, such as yeast.
activator
A protein that binds to DNA and stimulates transcription of a specific gene.
restriction fragment
The fragment of DNA that is produced by cleaving DNA with a restriction enzyme.
gene expression
Conversion of the information encoded in a gene first into messenger RNA and then to a protein.
histone acetylation
The attachment of acetyl groups to certain amino acids of histone proteins.
operator
Region of DNA that controls RNA polymerase's access to a set of genes with related functions.
siRNAs (small interfering RNAs)
RNAs of similar size and functions as miRNAs that inhibit gene expression.
restriction site
A specific sequence on a DNA strand that is recognized as a cut siteby a restriction enzyme.
recombinant DNA
A DNA molecule made in vitro with segments from different sources.
inducer
A specific small molecule that inactivates the repressor in an operon.
host range
The limited range of host cells that each type of virus can infect and parasitize.
enhancer
A DNA segment containing multiple control elements that can recognize certain transcription factors that stimulate the transcription of nearby genes.
sticky end
A single-stranded end of a double-stranded DNA restriction fragment.
cell differentiation
the process by which a cell becomes specialized for a specific structure or function.
episome
A genetic element that can exist either as a plasmid or as part of the bacterial chromosome.
frameshift mutation
Mutation occurring when the number of nucleotides inserted or deleted is not a multiple of three, resulting in improper grouping of nucleotides into codons.
RNA interference
Blocking gene expression by means of an miRNA silencing complex.
micro-RNA (miRNA)
small single stranded RNA molecules that bind to mRNA and can degrade mRNA or block its translation.
retrovirus
An RNA virus that reproduces by transcribing its RNA into DNA and then inserting the DNA into a cellular chromosome; an important class of cancer-causing viruses.
lysogenic cycle
A phage replication cycle in which the viral genome becomes incorporated into the bacterial host chromosome as a prophage and does not kill the host.
differential gene expression
The expression of different sets of genes by cells with the same genome.
epigenetic inheritance
Inheritance of traits transmitted by mechanisms not directly involving the nucleotide sequence.
control elements
segments of noncoding DNA in eukaryotic genes that help regulate transcription by binding to certain proteins.
restriction enzyme
A degradative enzyme that recognizes and cuts up DNA (including that of certain phages) that is foreign to a bacterium.
viral envelope
A membrane that cloaks the capsid that in turn encloses a viral genome.
capsid
The protein shell that encloses a viral genome. It may be rod-shaped, polyhedral, or more complex in shape.
transposon
A transposable genetic element that moves within a genome by means of a DNA intermediate.
cyclic AMP (cAMP)
A compound formed from ATP that acts as a second messenger.
mutagens
physical and chemical agents that interact with DNA to cause mutations
DNA methylation
The addition of methyl groups to bases of DNA after DNA synthesis; may serve as a long-term control of gene expression.
HIV (human immunodeficiency virus)
The infectious agent that causes AIDS. HIV is a retrovirus.
biotechnology
The manipulation of living organisms or their components to produce useful products.
Section 23
(50 cards)
cDNA library
A limited gene library using complementary DNA. The library includes only the genes that were transcribed in the cells examined.
nuclear transplantation
A technique in which the nucleus of one cell is placed into another cell that already has a nucleus or in which the nucleus has been previously destroyed.
gel electrophoresis
The separation of nucleic acids or proteins, on the basis of their size and electrical charge, by measuring their rate of movement through an electrical field in a gel.
genomic library
A set of thousands of DNA segments from a genome, each carried by a plasmid, phage, or other cloning vector.
polymerase chain reaction (PCR)
A technique for amplifying DNA in vitro by incubating with special primers, DNA polymerase molecules, and nucleotides.
therapeutic cloning
The cloning of human cells by nuclear transplantation for therapeutic purposes, such as the generation of embryonic stem cells to treat disease.
induction
The process by which neighboring cells can influence the determination of a cell.
photoautotrophs
Organisms that use light as a source of energy to synthesize organic substances.
genomic equivalence
All cells in an organism contain the same complement of genes. These are the same set of genes that are established in the fertilized egg.
oxidizing agent
Accepts electrons and becomes reduced.
denaturation
In proteins, a process in which a protein unravels and loses its native conformation, thereby becoming biologically inactive. In DNA, the separation of the two strands of the double helix.
totipotent
Cells that are able to develop into any type of cell found in the body.
cyclic photophosphorolation
Only Photosystem I works. ATP is made, no oxygen is produced, no water is split, no NADPH is made.
electroporation
A technique to introduce recombinant DNA into cells by applying a brief electrical pulse to a solution containing the cells. The pulse creates temporary holes in the cells' plasma membrane, through which DNA can enter.
photosystem
A cluster of pigments embedded into a thylakoid membrane.
bacterial artificial chromosome (BAC)
An artificial version of a bacterial chromosome that can carry inserts of 100, 000 to 500, 000 base pairs.
yeast artificial chromosome (YAC)
A cloning vector that has telomeres and a centromere that can accommodate large DNA inserts and uses the eukaryote yeast as a host cell.
reproductive cloning
Using a somatic cell from a multicellular organism to make one or more genetically identical individuals.
reducing agent
Donates electrons and becomes oxidized.
thylakoid
Flattened membranes in the chloroplast where the light reactions take place.
stomata
Microscopic pores in the leaf which lets CO2 in and O2 out. Also where water is lost.
stem cell
Unspecialized cell that can both reproduce itself indefinitely and differentiate into specialized cells of one or more types.
expression vector
A cloning vector that contains the requisite prokaryotic promoter just upstream of a restriction site where a eukaryotic gene can be inserted.
nucleic acid probe
Radioactively labeled nucleic acid molecule used to tag a particular DNA sequence.
veins
Bundles of xylem and phloem.
chlorophyll
Green pigment located within the chloroplasts.
DNA sequencing
Determining the exact order of the base pairs in a segment of DNA.
mesophyll
Spongy tissue in the interior of the leaf where most chloroplasts are found.
pluripotent
Able to give rise to multiple, but not all, cell types.
granum
Stack of thylakoids.
cytoplasmic determinants
Maternal substances in egg that influence the course of early development.
photolysis
In the thylakoid membranes of a chloroplast during light-dependant reactions, two molecules of water are split to form oxygen, hydrogen ions, and electrons.
Human Genome Project
An international collaborative effort to map and sequence the DNA of the entire human genome.
complementary DNA (cDNA)
DNA molecule made in vitro using mRNA as a template and the enzyme reverse transcriptase.
DNA ligase
A linking enzyme essential for DNA replication; catalyzes the covalent bonding of the 3' end of a new DNA fragment to the 5' end of a growing chain.
determination
The point during development at which a cell becomes committed to a particular fate due to cytoplasmic effects or to induction by neighboring cells.
Southern blotting
A hybridization technique that enables researchers to determine the presence of certain nucleotide sequences in a sample of DNA.
cloning
Making a genetically identical copy of DNA or of an organism.
noncyclic photophosphorolation
Photosystem II performs photolysis to provide electrons for the electron transport chain that drives a chemiosmotic gradient that produces ATP.
pigments
Molecules that absorb, reflect, or transmit light.
linkage map
A genetic map based on the frequencies of recombination between markers during crossing over of homologous chromosomes.
physical map
A genetic map in which the actual physical distances between genes or other genetic markers are expressed, usually as the number of base pairs along the DNA.
restriction fragment length polymorphisms (RFLPs)
differences in the restriction sites on homologous chromosomes that result in different restriction fragment patterns.
stroma
Fluid inside the chloroplast where the Calvin Cycle happens.
cloning vector
DNA molecules that can carry foreign DNA into a host cell and replicate there.
leaf
The major sites of photosynthesis in most plants.
light reaction
Part of photosynthesis that involves light. ATP and NADPH are produced. Takes place on the thylakoid membrane.
genetic engineering
The direct manipulation of genes for practical purposes.
nucleic acid hybridization
Base pairing between a gene and a complementary sequence on another nucleic acid molecule.
Equation of photosynthesis.
Section 24
(50 cards)
chlorophyll a
Only pigment that can participate directly in the light reactions.
dormancy
A condition typified by extremely low metabolic rate and a suspension of growth and development.
ovule
A structure that develops within the ovary of a seed plant and contains the female gametophyte.
calvin cycle
Carbon fixation process in photosynthesis. Forms sugar and other organic compounds.
anther
In an angiosperm, the terminal pollen sac of a stamen, where pollen grains containing sperm-producing male gametophytes form.
action spectrum
A profile of the relative performance of the different wavelengths in photosynthesis.
etiolation
Plant morphological adaptations for growing in darkness.
phototropism
Growth of a plant shoot toward or away from light.
cytokinins
A class of plant hormones that retard aging and act in concert with auxin to stimulate cell division, influence the pathway of differentiation, and control apical dominance.
complete flower
A flower that has all four basic floral organs: sepals, petals, stamens, and carpels.
p680
Reaction center chlorophyll in the photosystem II.
rubisco
The most abundant protein on earth. Performs Carbon Fixation in the Calvin Cycle.
de-etiolation
The changes a plant shoot undergoes in response to sunlight; also known informally as greening.
inflorescence
A group of flowers tightly clustered together.
style
The stalk of a flower's carpel, with the ovary at the base and the stigma at the top.
endosperm
In angiosperms, a nutrient-rich tissue formed by the union of a sperm with two polar nuclei during double fertilization. Provides nourishment to the developing embryo in angiosperm seeds.
ovary
In flowers, the portion of a carpel in which the egg-containing ovules develop.
tropism
A growth response that results in the curvature of whole plant organs toward or away from stimuli owing to differential rates of cell elongation.
petal
A modified leaf of a flowering plant; petals are the often colorful parts of a flower that advertise it to insects and other pollinators.
incomplete flower
A flower in which one or more of the four basic floral organs such as sepals, petals, stamens, or carpels are either absent or nonfunctional.
carbon fixation
The initial incorporation of carbon into organic compounds.
pollen tube
A tube that forms after germination of the pollen grain and that functions in the delivery of sperm to the ovule.
gibberellins
A class of related plant hormones that stimulate growth in the stem and leaves, trigger the germination of seeds and breaking of bud dormancy, and stimulate fruit development.
primary electron acceptor
Specialized molecule that shares a reaction center with the chlorophyll a molecule in the light reaction. traps high energy electron before it can return to ground state in the chlorophyll.
chemiosmosis
Process by which a Hydrogen pump pumps protons into the thylakoid membrane. H+ passively flows through the ATP synthase which leads to the creation of ATP.
multiple fruit
A fruit derived from an entire inflorescence.
receptacle
The base of a flower; the part of the stem that is the site of attachment of the floral organs.
absorption spectrum
A graph plotting a pigment light light absorption.
phosphoralation
Process of adding a phosphate group.
dioecious
If staminate and carpellate flowers are on different plants.
monoecious
If staminate and carpellate flowers are on the same plant.
stigma
The sticky part of a flower's carpel, which receives pollen grain.
abscisic acid (ABA)
A plant hormone that slows down growth, promotes seed dormancy and facilitates drought tolerance.
aggregate fruit
A fruit derived from a single flower that has more than one carpel.
p700
Reaction center cholophyll in the photosystem I.
pistil
A single carpel or a group of fused carpels in a flower.
seed coat
A tough outer covering of a seed, formed from the outer coat of an ovule.
self-incompatibility
The ability of a seed plant to reject its own pollen and sometimes the pollen of closely related individuals.
double fertilization
A mechanism of fertilization in angiosperms, in which two sperm cells unite with two cells in the embryo sac to form the zygote and endosperm.
auxin
Indoleacetic acid (IAA), a natural plant hormone that has a variety of effects, including cell elongation, root formation, secondary growth, and fruit growth.
coleoptile
Covers and protects the shoot as it grows upward.
reaction center
The location of the first light driven chemical reaction of photosynthesis.
radicle
An embryonic root of a plant.
carpel
The ovule-producing reproductive organ of a flower, consisting of the stigma, style, and ovary.
carotenoids
Accessory pigments that broaden the spectrum of colors that can drive photosynthesis.
hypocotyl
The part of a plant embryo directly below the cotyledons, forming a connection with the radicle.
sepal
A modified leaf in angiosperms that helps enclose and protect a flower bud before it opens.
stamen
The pollen-producing reproductive organ of a flower, consisting of an anther and a filament.
simple fruit
A fruit derived from a single carpel or several fused carpels.
fruit
A mature ovary of a flower that protects dormant seeds and often aids in their dispersal.
Section 25
(50 cards)
reception
The target cell's detection of a signal molecule coming from outside the cell.
saturated fats
bad for you; animals and some plants have it; solidifies at room temp.
totipotent
Stem cells with the potential to differentiate into any type of cell.
ethylene
The only gaseous plant hormone. Among its many effects are response to mechanical stress, programmed cell death, leaf abscission, and fruit ripening.
salicylic acid
A plant hormone that may be partially responsible for activating systemic acquired resistance to pathogens.
circadian rhythm
A physiological cycle of about 24 hours that is present in all eukaryotic organisms and that persists even in the absence of external cues.
photoperiodism
A physiological response to photoperiod, the relative lengths of night and day. An example of photoperiodism is flowering.
noncompetitive inhibition
inhibitor binds elsewhere on the enzyme; alters active site so that the substrate cannot bind
systemic acquired resistance (SAR)
A defensive response in infected plants that helps protect healthy tissue from pathogenic invasion.
topoisomerase
Enzyme that functions in DNA replication, helping to relieve strain in the double helix ahead of the replication fork.
receptor tyrosine kinase
A receptor with enzymatic activity that can trigger more than one signal transduction pathway at once, helping the cell regulate and coordinate many aspects of cell growth and reproduction.
apoptosis
Programmed cell death.
triple response
A plant growth maneuver in response to mechanical stress, involving slowing of stem elongation, a thickening of the stem, and a curvature that causes the stem to start growing horizontally.
chromatin
The complex of DNA and proteins that makes up a eukaryotic chromosome.
G-protein-linked receptor
A plasma membrane receptor that works with the help of a G-protein.
hypersensitive response (HR)
A plant's localized defense response to a pathogen
phospholipids
glycerol + 2 fatty acids + 1 phosphate group; makes up membrane bilayers of cells; hydrophobic interiors and hydrophillic exteriors
avirulent
A term describing a pathogen that can only mildly harm, but not kill, the host plant.
diacylglycerol (DAG)
A second messenger produced by the cleavage of a certain kind of phospholipid in the plasma membrane.
transduction
The binding of the signal molecule changes the receptor protein in some way.
enzymes
catalytic proteins that react in an induced-fit fashion with substrates to speed up that rate of reactions by lowering the activation energy
organic compounds
contain carbon; examples include lipids, proteins, and carbs
elicitors
A molecule that induces a broad type of host defense response
steriods
lipids whose structures resemble chicken-wire fence. include cholesterol and sex hormones
blue-light photoreceptors
A class of light receptors in plants. Blue light initiates a variety of responses, such as phototropism and slowing of hypocotyl elongation.
gene-for-gene recognition
A widespread form of plant disease resistance involving recognition of pathogen-derived molecules by the protein products of specific plant disease resistance genes.
jasmonic acid
An important molecule in plant defense against herbivores.
long-day plant
A plant that flowers only when the light period is longer than a critical length. Usually spring or early summer.
virulent
A term describing a pathogen against which a plant has little specific defense.
vernalization
The use of cold treatment to induce a plant to flower.
ligand-gated ion channel
Type of membrane receptor that has a region that can act as a "gate" when the receptor changes shape.
day-neutral plant
A plant whose flowering is not affected by photoperiod.
leaf abscission
Aging and dropping of leaves controlled by auxin and ethylene.
functional groups
amino (NH2), carbonyl (RCOR), carboxyl (COOH), hydroxyl (OH), phosphate (PO4), sulfhydryl (SH)
florigen
A flowering signal, not yet chemically identified, that may be a hormone or may be a change in relative concentrations of multiple hormones.
virulent
Viruses that reproduce only by the lytic cycle.
carbohydrates
used by cells for energy and stucture; monosaccharides (glucose), disaccharides (sucrose, maltose, lactose), storage polysaccharides (starch [plants], glycogen [animals]), structural polysaccharides (chitin [fungi], cellulose [arthropods])
photomorphogenesis
Effects of light on plant morphology.
oligosaccharins
A type of elicitor that is derived from cellulose fragments released by cell wall damage
fruit ripening
A burst of ethylene production in a fruit triggers the ripening process.
short-day plant
A plant that flowers only when the light period is shorter than a critical length. Usually fall or winter.
unsaturated fats
better for you, plants have it; liquifies at room temp.
PR protein
A protein involved in plant responses to pathogens (PR = pathogenesis-related).
response
The transduced signal finally triggers a specific cellular response.
fat
glycerol and three fatty acids
pH
logarithmic scale; <7 acidic, 7 neutral, >7 basic (alkaline); 4 is 10 times more acidic than 5
phytochromes
A class of light receptors in plants. Mostly absorbing red light, these photoreceptors regulate many plant responses, including seed germination and shade avoidance.
proteins
made with the help of ribosomes out of amino acids; serve many functions (transport, enzymes, cell signals, receptor molecules, structural components, and channels)
competitve inhibtion
inhibitor resembles substrate and binds to active site
repolarization
Return of the cell to resting state, caused by reentry of potassium into the cell while sodium exits the cell.
Section 26
(50 cards)
nucleus
found in eukaryotes; control center of cell; host for transcription, replication, and DNA
stomata
structure through which CO2 enters a plant, and water vapor and oxygen leave plant
photolysis
process by which water is split into hydrogen ions and oxygen atoms (light reactions)
aerobic respiration
glycolysis -> krebs cycle -> oxidative phosphorylation -> 36 ATP per glucose molecule
dehydration
two components brought together, producing H2O
autotroph
self-nourishing organism that is also known as a producer (plants)
centrioles
found in animal cells eukaryote; part of microtubule separation apparatus that assits cell division in animal cells
endergonic reaction
reaction that requires input of energy
binary fission
prokaryotic cell division; double the DNA, double the size, then split apart
pigment
molcule that absorbs light of a particular wavelength (chlorophyll, carotenoid, phycobilins)
anaerobic respiration (fermentation)
glycolysis -> regenerate NAD+ -> 2 ATP per glucose molecule
fermentation
process that regenerates NAD+ so glycolsis can begin again; occurs in absence of oxygen
chemiosmosis
coupling of the movement of electrons down the ETC with the formation of ATP using the driving force provided by the proton gradient; occurs in both cell respiration and photosynthesis to produce ATP
cell wall
found in prokaryotes and plant cells eukaryotes; protects and shapes the cell
hydrolysis
breaks down compounds by adding water
ATP synthase
enzyme responsible for using protons to actually produce ATP from ADP
mitochondria
found in eukaryotes; power plant of cell; hosts major energy-producing steps of respiration
osmosis
passive movement of water from the side of low solute concentration to the side of high solute concentration
fluid mosaic model
plasma membrane is selectively permeable phosolipid bilayer with proteins of various lengths and sizes interspersed with cholesterol amoung the phospholipids
exocytosis
process by which particles are ejected from the cell, similar to movement in a trash chute
plasma membrane
found in prokaryotes and eukaryotes; regulates what substances enter and leave a cell
CAM plants
plants close their stomata during the day, collect CO2 at night, and store the CO2 in the form of acids until it is needed during the day for photosynthesis
facilitated diffusion
assisted transport of particles across membrane (no energy input)
heterotrophs
organisms that must consume other organisms to obtain energy--consmers
integral proteins
proteins implanted within lipid bilayer of plasma membrane
smooth ER
found in eukaryotes; lipid synthesis, detoxification, carbohydrate metabolism; contains no ribosomes on cytoplasmic surface
peroxisome
found in eukaryotes; breakdown of fatty acids, detoxification of alcohol
oxidative phosphorylation
production of large amounts of ATP from NADH and FADH2; occurs in the mitochrondria; requires the presence of oxygen to proceed
lysosome
found in eukaryotes; contains enzymes that digest organic compounds; serves as cell's stomach
diffusion
passive movement of substances down their concentration gradient (from high to low concentrations)
cytoskeleton
found in eukaryotes; skeleton of cell; consists of microtubules, microfilaments, and intermediate filaments
exergonic reaction
reaction that gives off energy
vacuole
large in plant cells and small in animal cells; storage vaults of cells
chloroplast
found in plant cells eukaryotes; site of photosynthesis in plants
photophosphorylation
process by which ATP is made during light reactions
photosynthesis
process by which plants use the energy from light to generate sugar; occurs in chloroplasts; light reactions (thylakoid), and Calvin cycle (stroma)
Golgi
found in eukaryotes; modifies lipids, proteins to secrete or send to plasma membrane; contains ribosomes on cytoplasmic surface
C4 plants
plants that have adapted their photosynthetic process to more efficiently handle hot and dry conditions
ribosome
found in prokaryotes and eukaryotes; host for protein synthesis; form in nucleolus
C4 photosynthesis
process that first converts CO2 into a 4-carbon molcule in the mesophyll cells, converts that product to malate and then shuttles it to the bundle sheath cells, where the malate releases CO2 and rubisco picks it up as if all were normal
redox
electron transfer reactions
alcohol fermentation
occurs in fungi, yeast, and bacteria; causes conversion of pyruvate to ethanol
rough ER
found in eukaryotes; synthesizes proteins to secrete or send to plasma membrane; contains ribosomes on cytoplasmic surface
glycolysis
conversion of 1 glucose molecule into 2 pyruvate, 2 ATP, and 2 NADH; occurs in the cytoplasma, and in both aerobic and anaerobic respiration; must have NAD+ to proceed
Krebs cycle
conversion 1 pyruvate molecule into 4 NADH, 1 FADH2, 1 ATP, H2O, and CO2; occurs twice for each glucose to yeild double the products above; occurs in the mitochondria
cell cycle
growth 1 -> synthesis -> growth 2 -> mitosis
endocytosis
phagocytosis of particles into cell through the use of vesicles
active transport
movement of substances against concentration gradient (low to high concentrations; requires energy input)
lactic acid fermentation
occurs in humans and animal muscles; causes conversion of pyruvate -> lactate; causes cramping sensation when oxygen runs low in muscles
transpiration
loss of water via evaporation through the stomata
Section 27
(50 cards)
chromosomal disorders
deletion, inversions, duplications, and translocations
haploid (n)
one copy of each chromosome
DNA replication
occurs in S-phase, semiconservative, built in 5' to 3' direction
pedigree
family tree used to describe genetic relationships
sex-linked traits
passed along the X chromosome; more common in males then females
multiple alleles
traits that correspond to more than two alleles
mRNA
blueprints for proteins
intermediate inheritance
heterozygous individual shows characterstics unlike either parent
RNA
contains A, G, C, and U; singled stranded
missense mutation
subsitution of wrong nucleotide into DNA; still produces a protein
rRNA
make of ribosomes
polygenetic traits
traits that are affected by more then one gene (eye color or skin color)
spermatogenesis
the process of male gamete formation (four sperm from one cell)
monohybrid cross
cross involving one character (3:1 phenotype ratio)
autosomal chromosome
chromosome not involved in gender
DNA
contains A, G, C, and T; arranged in double helix of two strands held together by hydrogen bonds
diploid (2n)
two copies of each chromosome
X inactivation
one of two X chromosomes is randomly inactivated and remains coiled as a Barr body
cell division control mechanisms
growth factors, checkpoints, density-dependent inhibition, and cyclins and protein kinases
life cycles
sequences of events that make up the reproductive cycle of an organism
law of segregation
the two alleles for a trait separate during the formation of gametes--one to each gamete
plants life cycle
zygote (2n) -> sporophyte (2n) -> spores (n) -> gametophyte (n) -> gametes (n) -> zygote (2n)
dihybrid cross
cross involving two different characters (9:3:3:1 phenotype ratio)
holandric trait
trait that is inherited via the Y chromosome
homologous chromosomes
chromosomes that are similar in shape, size, and function
linkage map
genetic map put together using crossover frequencies
growth factors
factors then when present, promote growth, and when absent, impede growth
autosomal dominant disorders
Huntington disease and achondroplasia
codominace
both alleles express themselves fully in a Yy individual
linked genes
genes that lie along the same chromsome and do not follow the law of independent assortment
tRNA
brings acids to ribosomes
character
heritable feature, such as flower color
source of variation
crossover, 2^n possible gametes that can be formed, random pairing of gametes
law of dominance
if two opposite pure-breeding varieties are crossed, all offspring resemble dominant parent
fungi life cycle
zygote (2n) -> multicellular orgainsm (n) -> gametes (n) -> zygote (2n)
autosomal recessive disorders
Tay-Sachs, Cystic fibrosis, sickle cell anemia, phenylketonuria
density-dependent inhibition
cell stops growing when certain density is reached
crossover
a form of genetic recombination that occurs during prophase I of meiosis
frameshift mutation
deletion or addition of nucleotides; shifts reading frame
law of indendent assortment
inheritance of one trait does not interfere with the inheritance of another trait
oogenesis
the process of female gamete formation (one ovum from each cell)
pleiotropy
a single gene has multiple effects on an organism
nondisjunction
error in which homologous chromosomes do not separate properly
epistasis
a gene at one locus alters the phenotypic expression of a gene at another locus
cyclins and protein kinases
cyclin combines with CDK to form a structure known as MPF that pushes cell into mitosis when enough is present
incomplete dominance
Yy produces a intermediate phenotype between YY and yy
sex determination
males are XY, females are XX
human life cycle
zygote (2n) -> multicellular orgainsm (2n) -> gametes (n) -> zygote (2n)
checkpoints
a cell stops growing to make sure it has the nutrients and raw materials to proceed
cytokinesis
physical separation of newly formed daughter cells of cell division
Section 28
(50 cards)
selection types
directional, stabilizing, disruptive, sexual, and artifical
repressor
protein that prevents the binding of RNA polymerase to promoter site
retrovirus
RNA virus that carries with it reverse transcriptase (HIV)
promoter
base sequence that signals start site for transcription
polymerase chain reaction (PCR)
produces large quanties of sequence in short amount of time
stabilizing selection
selection for the mean of the population; reduces variation of a population
artifical selection
human intervention in the form of selective breeding
prion
virus that converts host brain proteins into misshapen proteins
phage
virus that infects bacteria
natural selection
process by which characters or traits maintained or eliminated in a population based on their contribution to the differential survival and reproductive succes of their "host" organism
bacteria
prokaryotic cell consists of one double strand circular DNA molecule; reproduce by binary fission
balanced polymorphism
two phenotypic variants become so different that the two groups stop interbreeding
nonsense mutation
subsitution of wrong nucleotide into DNA that produces an early stop codon
genetic drift
change in allele frequencies because of chance events
transcription
process by which mRNA is synthesized on a DNA template
mutation
random changes in DNA can introduce new alleles into a population
sexual selection
certain characters are selected for because they aid in mate acquisition
viruses
parastic infectious agent unable to survive outside the host; can obtain DNA or RNA, or have a viral envelope
translation
process by which the mRNA specified sequence of amino acids is lined up on a ribosome for protein synthesis
restriction enzymes
enzymes that cut DNA at a paticular sequences, creating sticky ends
adaptive radiation
rapid series of speciation events that occur when one or more ancestral species invades a new environment
codon
triplet of nucleotides that codes for a particular amino acid
operator
short sequence near the promoter that assists in transcription by interacting with transcription factors
conjugation
transfer of DNA between two bacterial cell connected by sex pili
vector
mover of DNA from one source to another
transformation
uptake of foreign DNA from the surrounding environment
lytic cycle
one in which the virus is actively reproducing and kills the host cell
inducer
molecule that binds to and inactivates a repressor
cloning
somewhat slow process by which a desired sequence of DNA is copied numerous times
RNA processing
introns (noncoding) are spliced out, exon (coding) glued together
operon
on/off switch for transcription, allows for production of genes only when needed
hertiability
the traits to be selected for must be able to be passed along to offspring
directional selection
members at one end of a spectrum are selected against, and the population shifts toward that end
viroids
tiny plant viruses
sympatric speciation
interbreeding stops even though no physical barrier prevents it
adaption
a trait that, if altered, affects the fitness of an organism
allopatric speciation
interbreeding stops because some physical barrier splits the population into two
lysogenic cycle
one in which the virus lie dormant within the DNA of the host cell
gel electrophoresis
technique used to separate DNA according to size. DNA moves from - to +
transduction
movement of genes from one cell to another by phages, which incorporated by crossover
disruptive selection
selects for the two extremes of the population; selects against the middle
variation
differences must exist between individuals
specialized transduction
virus leaving lysogenic cycle brings host DNA with it into phage
differential reproductive success
there must be variation amoung parents in how many offspring they produce as a result of the different traits that the parent have
mutation
change in allele frequencies due to random genetic change in an allele
modes of evolution
genetic drift, gene flow, mutation, natural selection
generalized transduction
lytic cycle accidently places host DNA into a phage, which is brought to another cell
balanced polymorphism
the maintainance of two or more phenotypic variants
gene flow
change in allele frequencies as genes move from one population to another
polyploidy
condition in which individual has higher than normal number of chromosomes sets
Section 29
(50 cards)
plant hormones
abscisic acid, auxin, cytokinins, ethylene, gibberellins
gibberellins
stem elongation, induce growth in dormant seeds, buds, flowers
divergent evolution
two related spevies evolve in a way that makes them less similar
endosymbiotic theory
eukaryotes originated from symbiotic partnership of prokaryotic cells
parenchyma cells
play a role in storage, secrection, and photosynthesis in cells
collenchyma cells
provide flexible and mechanical support; found in stems and leaves
taxonomy
classification of organisms based upon the presence or absence of shared characterstics: kingdom -> phylum -> class -> order -> family -> genus -> species
phototropism
plant's growth in response to light
vascular cambium
gives rise to secondary xylem/phloem; runs entire length of plant
anatomy of plants
tissue systems are divided into ground, vascular, and dermal
cork cambium
produces protective covering that replaces epidermis during secondary growth
thigmotropism
plant's growth in response to touch
five kingdom system
monera -> Protista -> plantae -> Fungi -> animalia
dermal tissue
protective outer coating for plants: epidermis
photoperiodism
response of a plant to the change in length of days
ground tissue
the body of the plants is divided into collenchyma cells, parenchyma cells, and sclerenchyma cells
phloem
transports sugar in plants
lipase
major fat digesting enzyme of the body
fibrous root system
anchoring systsem that does not go deep down into the soil
homologous character
traits similar between organisms that arose from a common ancestor
plant trophisms
gravitropism, phototrophism, thigmotropism
taproot system
dicots; system that divides into lateral roots that anchor the plant
pepsin
main digestive enzyme of the stomach that breaks down proteins
cytokinins
promote cell division, leaf enlargement, slow aging of leaves
sclerenchyma cells
protects seeds and support the plants
gradualism
evolutionary change is slow and steady process
secondary growth
increased width of plant (occurs in region of lateral meristems)
vestigil character
character contained by organism that is no longer functionally useful
vascular tissue
xylem and phloem
hetertroph theory
theory that describes how life evolved from original heterotrophs
amylase
enzyme that breaks down starches in the diet
punctuated equilibria
evolutionary change occurs in rapid bursts separated by large periods of no change
auxin
stem elongation, gravitrophism, phototropism
six kingdom system
Archaebacteria -> Eubacteria -> Protista -> Planae -> Fungi -> Animalia
trypsin and chymotrypsin
major protein digesting endopeptidases of the small intestine
convergent character
traits similar to two or more organisms that do not share common ancestor; parallel evolution
xylem
transports water and minerals in plants
respiratory pathway
nose/mouth -> pharynx -> larynyx -> trachea -> bronchi -> bronchioles -> alveoli
circulatory system
bloodflow= left side of heart -> aorta -> via arteries to organs and muscles -> into vena cava -> right side of heart -> lungs -> left side of heart
types of roots
taproot system and fibrous root system
convergent evolution
two unrelated species evolve in a way that makes them more similar
ethylene
ripens fruit and causes leaves to fall
bile salts
major emulsifer of fat
abscisic acid
inhibits cell growth, helps close stomata
Hardy-Weinberg equilibrium
p + q = 1, p2 + 2pq + q2 = 1; evolution is not occuring; the rules for this are no mutations, no gene flow, no genetic drift, no natural selection, and random mating
small intestine
most of the digestion and absorption of food occurs in the _________
maltase, lactase, and sucrase
carbohydrate digesting enzymes of the small intestines
primary growth
increased length of plants (occurs in region of apical meristem)
gravitropism
a plant's growth in response to gravity
digestive system
digestion begins in mouth, continues in the stomach, and completes in the intestine
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testosterone
stimulates sperm production; develops male secondary sex characterstics
large intestine
reabsorbs water and packs the indigestible food into feces
ANS
controls involuntary activities of body
ethology
study of animal behavior
FSH
stimulates production of eggs or sperm
parathyroid hormone (PTH)
increases blood Ca2+ involved in bone maintenance
TSH
increases release of thyroid hormone
ADH
controls water absorption in the excretory system
anterior pituitary hormones
FSH, LH, TSH, STH, ACTH, and prolactin
hypothalamus
regulates hunger, thirst, and temperature
STH
increases growth
LH
stimulates ovulation, increases estrogen/progesterone release
ACTH
increases secrection of adrenal cortical hormones
primary immune response (humoral immunity)
antigen invader -> B cell meets antigen -> B cell differentiates into the plasma cells and memory cells -> plamsa cells produce anitbodies -> antibodies eliminate antigen
amygdala
emotion control center
behavioral ecology
the study of interaction between animals and their environment
LH
stimulates the ovulation and production of estrogen and progesterone in females; stimulates production of testosterone and sperm in males
primary sex characteristics
sexual organs that assist in reproduction
fixed action pattern
preprogrammed response to a stimulus
aldosterone
controls sodium reabsorption in the excretory system
glucagon
increases glycogen breakdown
insulin
increases glycogen formation
pancreatic hormones
insulin and glucagon
cell-mediated immunity
involves T cells and direct cellular response to an invasion. defense against viruses
cerebellum
controls coordination and balance
oxytocin
stimulates uterine contraction and milk ejection
estrogen
made in ovaries; increases release of LH; develops female secondary sex characteristics
positive feedback
horomone acts directly, or indirectly, cause increased secretion of the hormone
cortisol
chronic stress hormone
FSH
stimulate oogenesis in females and spermatogenesis in males; creates follicle that surrounds the primary oocyte during development
excretory system
kidneys -> minor and major calyces -> renal pelvis -> bladder via the ureter -> out of the body via the urethra
habituation
loss of responsiveness to unimportant stimuli or stimuli that provide no feedback
imprinting
innate behavior learned during critical period early in life
SNS
controls skeletal muscles and voluntary actions
sex hormones
progestrone, estrogen, and testosterone
associative learning
one stimulus is associated with another (classical conditioning)
negative feedback
hormone acts to directly, or indirectly, inhibit further release of the hormone of interest
nephron
functional part of the kidney
secondary sex characteristics
physical characteristics that differ men and women
secondary immune response
antigen invader -> memory cells recogize antigen and pump out antibodies much quicker than primary response -> antibodies eliminate antigen
prolactin
controls lactogenesis, decreases secretion of GnRH
progestrone
involved in menstrual cycle and pregnancy
medulla
controls involuntary actions such as breathing
posterior pituitary hormones
ADH and oxytocin
nonspecific immunity
nonspecific prevention of enterance of invaders into the body
specific immunity
multilayered defense mechanism-- first line of defense: phagocyctes, macrophages, neutrophils, complement; second line of defense: B cells and T cells
adrenal gland hormones
aldosterone and cortisol
GnRH
causes pituitary to release LH and FSH
excretory system hormones
ADH and aldosterone
aldosterone
regulates blood sodium concentration
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visual communication
communication through the visual cues, such as the tail feather displays of peacocks
water biomes
freshwater and marine biomes
operant conditioning
trial-and-error learning
desert
driest land biome
mutualism
both organisms reap benefits from the interaction
abiotic components
nonliving players in an ecosystem
population
collection of individuals of the same species living in the same geographic region
taiga
lengthy cold, wet winters; lots of conifers
trophic levels
hierarchy of energy levels on a planet
observational learning
learning by watching someone else do it first
dominance hierarchies
ranking of power amoung the members of a group; subject to change
insight learning
ability to reason through a problem the first time through with no prior experience
community
collection of populations of species in a geographic area
biosphere
communities and the ecosystems of the planet
tactile communciation
communication through the use of touch, such as a handshake
aposematic coloration
warning coloration adopted by animals that posses a chemical defense mechanism
taxis
reflex movement toward or away from a stimulus
chemical communication
communication through the use of chemical signals, such as pheramones
reciprocal altruism
animals behave altruistically toward others who are not relatives
temperate grasslands
most fertile soil of all biomes
Oxygen
Oxygen is an element with symbol O and atomic number 8. It is a highly reactive nonmetal and oxidizing agent. In living organisms, oxygen is used in respiration and in a number of organic molecules.
deceptive markings
patterns that cause an animal to appear larger or more dangerous than it really is
migration
cyclic movement of animals over long distances according to the time of year
biotic components
living organisms of ecosystem
Mullerian mimicry
two aposemetrically colored species have similar coloration pattern
ecosystem
community and its environment
commensalism
one organism benefits while the other is unaffected
parasitism
one organism benefits at another's expense
savanna
grasslands, home to herbivores
primary succession
occurs in area devoid of life that contains no soil
Batesian mimicry
animal that is harmless copies the apperance of an animal that is dangerous
kinesis
change in the speed of movement in response to a stimulus; organisms will move faster in bad environments and slower in good environments
cryptic coloration
colring scheme that allows organism to blend into colors of environment
deciduous forest
cold winters and warm summers
agnostic behavior
conflict behavior over access to a resource; often a matter of which aniaml can mount the most threatening display and scare the other into submission
foraging
feeding behavior of an individual
biotic potential
maximum growth rate for a population
limiting factors
factors that keep population size in check
secondary succession
occurs in area that once had stable life but was disturbed by major force fire
Elements
Elements are substances that cannot be broken down into simpler substances by chemical means.
audiotory communication
communication through the use of sound, such as the chirping of frogs in the summer
territoriality
defense of territory to keep others out
tropical forest
great diversity of species in biomes
inclusive fitness
the ability of individuals to pass their genes not only through the production of their offspring, but also by providing aid to enable closely related individuals to produce offspring
tundra
permafrost, cold winters, short shrubs
carrying capcity
maximum number of individuals that a population can sustain in a given environment
altruistic behavior
action in which an organism helps another at its own expense
predation
one species, the predator, hunts the other, the prey
competition
both species are harmed by the interaction
optimal foraging
natural selection favors those who choose foraging strategies that maximize the differential betwen cost and benefits
Section 32
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Disaccharides
Disaccharides are formed by two sugar molecules combining together through dehydration synthesis. An example of a disaccharide is maltose, make by linking two glucose molecules.
Adhesion
Adhesion refers to the tendency of water molecules to stick to other substances, which accounts for the phenomenon of capillary action.
Non-polar covalent
A non-polar covalent bond is a covalent bond in which the electrons are shared equally between the atoms.
Side chain
Side chain is another name for an R group, and is a group of atoms attached to the main part of a molecule and having a ring or chain structure.
Dehydration synthesis
Dehydration synthesis, or condensation, is the process by which two molecules come together by the loss of a water molecule, such as the forming of maltose from two glucose molecules.
Carbohydrates
Carbohydrates are organic compounds that contain carbon, hydrogen, and oxygen, usually in a ratio of 1:2:1.
Ionic bond
An ionic bond is formed between two atoms when one or more electrons are transferred from one atom to the other. In this case, one atom becomes negatively charged and one atom becomes positively charged.
Atom
An atom is the smallest unit of an element that retains its characteristic properties; they are the building blocks of the physical world.
Hydrolysis
Hydrolysis is the opposite process of dehydration synthesis by which molecules are broken up by the addition of a water molecule, such as the formation of two glucose molecules from a maltose.
Fructose
Fructose is a monosaccharide that is a common sugar in fruits. It is a six-carbon sugar with the chemical formula C-6, H-12, O-6.
Nucleus
The nucleus is the positively charged core in an atom made up of neutrons and protons.
Neutrons
Neutrons are uncharged subatomic particles found in an atom's nucleus.
Inorganic compounds
Inorganic compounds are compounds that do not contain carbon atoms (except for some simple carbon compounds such as carbon oxides)
pH scale
The pH scale is a logarithmic scale to measure acidity, with 1 being most acidic, 14 being most basic, and 7 being neutral.
Monosaccharides
Monosaccharides are the simplest sugars which serve as an energy source for cells. The two most common monosaccharides are glucose and fructose.
Glycosidic bond
A glycosidic bond is a covalent bond in which a carbohydrate binds to another group, which could also be a carbohydrate. A glycosidic bond is found between the two glucose molecules in maltose.
R group
An R-group is any group in which the carbon or hydrogen is attached to the rest of the molecule.
Capillary action
Capillary action is the ability of water, or other liquids, to travel against gravity in a thin vessel and accounts for the ability of water to rise up the roots, trunks, and branches of trees.
Electrons
Electrons are negatively charged subatomic particles that spin around the nucleus.
Chemical bond
The atoms of a compound are held together by chemical bonds, which may be ionic bonds, covalent bonds, or hydrogen bonds.
Glycogen
Glycogen is a multi-branch polysaccharide of glucose that is the main storage of glucose in the body.
Trace elements
Trace elements are elements required by an organism in very small quantities. Trace elements include iron, iodine, and copper.
Surface tension
Surface tension is a property of water, due to the cohesiveness of its molecules, that allows things (sometimes organisms) to float and stride on its surface without sinking.
Acidic
A solution is acidic if it contains excess hydrogen ions. It will have a pH less than 7.
Neutral
A solution is neutral, neither basic nor acidic, if it has a pH of 7.
Carboxyl group
Carboxyl groups are weak acids that are common in many organic molecules including amino acids and fatty acids.
Heat capacity
Heat capacity refers to the ability of a substance to store heat and is the quantity of heat required to change the temperature of a substance by 1 degree. Water has a high heat capacity, allowing it to keep a fairly stable temperature in our bodies and in the environment.
Amino acids
Amino acids are organic molecules that serve as the building blocks of proteins. They contain carbon, hydrogen, oxygen, and nitrogen atoms. Every amino acid has four parts: an amino group, a carboxyl group, a hydrogen, and an R group.
Polymer
A polymer is a molecule with repeating subunits of the same general type, such as polysaccharides.
Starch
Starch is a polysaccharide of alpha glucose molecules bound together and is produced by most green plants as an energy store.
Polar covalent
A polar covalent bond is a covalent bond in which the electrons are shared unequally - one atom attracts electrons more than the other.
Organic compounds
Organic compounds are compounds that contain carbon and include carbohydrates, lipids, proteins, and nucleic acids.
Protons
Protons are positively charged subatomic particles that are found in an atom's nucleus.
Chemical reaction
A chemical reaction describes a chemical change in which reactants react to form products chemically different from the reactants.
Polysaccharides
Polysaccharides are made up of many repeated unites of monosaccharides, and is therefore a type of polymer. The most common polysaccharides are starch, cellulose, and glycogen. Polysaccharides are often storage forms of sugar.
Cellulose
Cellulose is a polysaccharide of beta glucose molecules that is a major part of the cell wall in plants and is used to lend structural support.
Ions
An ion is a charged form of an atom.
Glucose
Glucose is the most abundant monosaccharide and is a six-carbon sugar with the chemical formula C-6, H-12, O-6. Glucose comes in two forms: alpha glucose and beta glucose, which differ simply by a reversal of the H and OH of the first carbon.
Hydrogen
Hydrogen is an element with symbol H and atomic number 1. Hydrogen combines with non-metallic elements to form water and other organic compounds.
Compound
A chemical compound is formed when two or more different types of atoms are combined in a fixed ration.
Hydrogen bonds
Hydrogen bonds are intermolecular attractions that form when a hydrogen bond that is covalently bonded to one electronegative atom that it also attracted to another electronegative atom. Hydrogen bonds are individually weak but are strong when present in large numbers.
Carbon
Carbon is an non mental element with symbol O and atomic number 6. It is the second most abundant element in living organisms and is present in all organic compounds.
Amino group
An amino group is a functional group and is found in organic compounds known as amines.
Cohesion
Cohesion refers to the tendency of water molecules to stick together and allows water to have a high surface tension.
Plastids
Plastids are double membrane bound organelles that temporarily store starch in plants. Plastids include chloroplasts, chromoplasts, and leucoplasts.
Basic
A solution is basic if it releases hydroxide ions when added to water. These solutions are said to be alkaline and are usually slippery.
Covalent bond
A covalent bond is formed when electrons are shared between atoms and can be polar or non-polar.
Polar
A molecule is polar if it has partially positive and partially negative charged ends, such as water.
Nitrogen
Nitrogen is an element with the symbol N and atomic number 7. In biology, nitrogen is important as it is found in a number of organic compounds and is used in fertilizers and antibiotics.
Isotopes
Atoms that have the same number of protons but differ in the number of neutrons in the nucleus are called isotopes.
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Hydrophilic
A hydrophilic molecule is a molecule that mixes with water because it is polar, such as a phosphate head in a lipid.
Cholesterol
Cholesterol is a steroid that is found in the phospholipid bilayer because it helps stabilize membrane fluidity in animal cells.
Cells
The cell is the basic unit of structure of function in life and is what all living things are composed of.
Organelles
Organelles are small units suspended in the cytoplasm which carry out a specific function to help the cell.
Phospholipid bilayer
The phospholipid bilayer is the double layered plasma membrane that surround cells.
Neutral fats
Neutral fats are non polar, uncharged triglycerides that have no acidic or basic groups.
Carbohydrate side chains
A carbohydrate side chain is attached to the surface of some proteins found only on the outer surface of the plasma membrane.
Cytoplasm
Cytoplasm is a thick solution that fills each cell and contains the organelles. The cytoplasm is composed of water, salt, and proteins and helps contain the organelles and may have important enzymes to break down large molecules.
Polyunsaturated
A polyunsaturated fatty acid has many double bonds within the fatty acids.
Protein
A protein is a polypeptide, a chain of amino acids, that twists and folds on itself.
Peptide bond
A peptide bond is the bond between two amino acids.
Fats
A neutral fat is the simplest lipid and consists of three fatty acids and one molecule of glycerol, also known as a triglyceride.
Glycerol
Glycerol is a simple polyol (sugar alcohol) compound that is found in fats.
Peripheral proteins
Peripheral proteins are proteins that are loosely associated with the lipid bilayer and only temporarily attach to the membrane. They are located on the inner or outer surface of the membrane.
Chromosomes
DNA is organized into large structures called chromosomes in the nucleus.
Ribonucleic acid (RNA)
RNA is a nucleic acid that has a ribose sugar, a phosphate group, and a nitrogen base. RNA is important because it has an essential role in protein synthesis.
Nucleic acids
Nucleic acids are organic compounds that contain carbon, hydrogen, oxygen, nitrogen, and phosphorus. They are made up of simple units called nucleotides and include deoxyribonucleic acid and ribonucleic acid.
Deoxyribonucleic acid (DNA)
DNA is a nucleic acid that has a deoxyribose sugar, a phosphate group, and a nitrogen base. DNA is important because it contains genes, and it is kept in the nucleus of cells.
Autotrophs
Autotrophs, or producers, are organism that are able to make their own food using solar or chemical energy.
Dipeptide
When two amino acids join they form a dipeptide. In a dipeptide, the carboxyl group of one amino acid combines with the amino group of another amino acid.
Hydrophobic
A hydrophobic molecule is a molecule that does not mix with water because it is non polar, such as a fatty acids.
Saturated
If a fatty acid is saturated, it means it has a single covalent bond between each pair of carbon atoms.
Polypeptide
If a group of amino acids are joined together in a chain, the resulting organic compound is a polypeptide, which is the primary structure of a protein.
Steriods
Steroids are a class of lipids that have a basic structure of four linked carbon rings and include cholesterol, vitamin D, and a variety of hormones.
Channel proteins
Channel proteins are membrane proteins that form channels that selectively allow the passage of certain ions or molecules.
Miller and Urey
Miller and Urey were scientists who, in 1953, simulated the conditions of primitive Earth in a laboratory. They put the gases theorized to be abundant in the early atmosphere into a flask, struck them with electrical charges in order to mimic lighting, and organic compounds similar to amino acids appeared.
Phospholipid
Phospholipids are a class of lipids that contain two fatty acids tails and one negatively charged phosphate head. They are extremely important in their unique properties with regard to water.
Ester linkage
The linkage formed between the glycerol molecule and the fatty acids in a fat is the ester linkage. This bond is formed through dehydration synthesis.
Unsaturated
If a fatty acid is unsaturated it means it has adjacent carbons that are joined by double bonds instead of single bonds.
Transmembrane proteins
Transmembrane proteins are integral proteins that do not extend all the way through the membrane.
Flagella
Flagella are long projections on a cell used for motility. They are often found on single cell organisms but are sometimes present in larger organisms, such as on sperm.
Oils
Oils are a type of lipid and are triglycerides that are liquid.
Recognition and adhesion proteins
Recognition and adhesion proteins, such as glycoproteins, are exposed on the extracellular surface and play a role in cell recognition and adhesion
Electron microscopes
Electron microscopes are used to study detailed structures of a cell that cannot be easily seen or observed by light microscopy. They are capable of resolving structures a small as a few nanometers in length, such as individual virus particles or the pores on the surface of the nucleus.
Prokaryotic cells
Prokaryotic cells are much smaller than eukaryotic cells and lack both a nucleus and membrane bound organelles. In a prokaryote, circular DNA lies free in the nucleoid . Most prokaryotes have a cell wall composed of peptidoglycan and may also have ribosomes or flagella.
Receptor proteins
Receptor proteins are membrane proteins that serve as docking sites for proteins of the extracellular matrix or hormones.
Oparin and Haldane
Oparin and Haldane were two scientists who proposed in the 1920s that the primitive atmosphere contained the following gases: methane, ammonia, hydrogen, and water. They believed that these gases collided, producing chemical reactions that eventually led to organic molecules.
Eukaryotic cells
Eukaryotic cells contain a nucleus and cytoplasm filled with membrane bound organelles. Eukaryotic cells include fungi, protists, plant cells, and animal cells.
Fluid-mosaic model
The fluid-mosaic model refers to the arrangement of phospholipids and proteins in the plasma membrane of cells.
Heterotrophs
Heterotrophs are living organism that rely on organic molecules for food, and are also known as consumers.
Plasma membrane
The plasma membrane is a double layered structure made up of phospholipids and proteins that serves as an outer envelope for cells. In the membrane, hydrophobic fatty acid tails face inwards and hydrophilic phosphate heads face outwards. The membrane is semi-permeable and regulated the movement of substances in and out of the cell.
Nucleotides
Nucleotides are simple units that make up nucleic acids. A nucleotide consists of a nitrogen base, a phosphate group, and a five carbon sugar (ribose or deoxyribose).
Light microscopes
Light microscopes, also known as compound microscopes, are used to study stained or living cells. They can magnify the size of an organism up to 1,000 times.
Amphipathic
An amphipathic molecule has both a hydrophilic region and a hydrophobic region, such as a phospholipid.
Integral proteins
Integral proteins are firmly bound to the plasma membrane and are amphipathic.
Functional group
A functional group is a distinctive group of atoms that play a large role in determining the chemical behavior of the compound they are a part of. In amino acids, functional groups include the carboxyl group and the amino group.
Transport proteins
Transport proteins are membrane proteins that form pumps that use ATP to actively transport solutes across the membrane.
Lipid
A lipid is an organic molecule consisting of carbon, hydrogen, and oxygen atoms and includes fats, oils, phospholipids, and steroids. Lipids are important because they function as structural components of cell membranes, sources of insulation, and a means of energy storage.
Nucleoid
The nucleoid is the area in a prokaryotic cell in which the circular DNA molecule lies free in the cell.
Adhesion proteins
Adhesion proteins are membrane proteins that form junctions between adjacent cells.
Section 34
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Endergonic reactions
Endergonic reactions are those in which the products have more energy than the reactants, so energy is required as an input.
Microtubule Organizing Centers (MTOCs)
The MTOC is a structure found in eukaryotic cells from which microtubules emerge. MTOCs have two main functions: the organization of eukaryotic cilia and flagella, and the organization of the mitotic and meiotic spindle apparatus.
Coenzymes
Factors that assist enzymes in catalyzing a reaction are known as coenzymes. Vitamins are examples of organic coenzymes. Coenzymes accept electrons and pass them along to another substrate. NAD+ and NADP+ are two examples of such enzymes.
Nucleolus
The nucleolus is the most visible structure within a cell's nucleus and is where rRNA is made and ribosomes are assembled.
Vacuoles
Vacuoles are fluid-filed sacs that store water, food, wastes, salts, or pigment. They are found in both animal and plant cells, but much larger in plant cells.
Tubulin
Tubulin is the protein of which microtubules are made up of.
Paramecium
Paramecium is a unicellular ciliated protozoan.
Microtubules
Microtubules, which are made up of the protein tubulin, participates in cellular division and movement. These small fibers are an integral part of centrioles, cilia, and flagella.
Simple diffusion
Simple diffusion, or passive transport, refers to the movement of substance down the concentration gradient, which uses no energy.
Mitochondria
The mitochondria is an organelle that converts the energy from organic molecules into useful energy for the cell through cellular respiration.
Intercellular junctions
Intercellular junctions are strucutres between cells that allow neighboring cells to form strong connections with each other, prevent passage of materials, or establish rapid communication between adjacent cells. The three types of intercellular contact in animal cells are: desmosomes, gap junctions, and tight junctions.
Cytoskeleton
The cytoskeleton is a network of fibers that holds the cell together and enables it to keep its shape. These fibers include microtubules and microfilaments.
Exocytosis
Exocytosis is the transportation of large particles out of the cell, by the fusion of a vesicle with the plasma membrane.
Osmosis
Osmosis is the diffusion that involves the movement of water. When osmosis occurs through a lipid bilayer it moves through membrane proteins called aquaporins.
Endoplasmic reticulum (ER)
The endoplasmic reticulum is a continuos channel that extends into many regions of the cytoplasm. The rough ER contains many ribosomes on its surface and generates proteins, which are then trafficked to or across the plasma membrane. The smooth ER lacks ribosomes and makes lipids, hormones, and steroids, and breaks down toxic chemicals.
Pinocytosis
Pinocytosis is endocytosis during which the cell ingests liquids.
Exergonic reactions
Exergonic reaction are those in which the products have less energy than the reactants, so energy is given off during the reaction.
Receptor-mediated endocytosis
Receptor-mediated endocytosis involves cell surface receptors that are covered in clathrin-coated pits. When a particle bind to one of these receptors, the ligand is brought into the cell by the folding in of the cell membrane, forming a vesicle.
Enzyme specificity
Enzyme specificity is the concept that each enzyme catalyzes only one kind of reaction.
Adenosine triphosphate
Adenosine triphosphate, or ATP, is the energy molecule used by the cell, synthesized in the mitochondria.
Gap juntions
Gap junctions are protein complexes that form channels in membranes and allow communication between the cytoplasm of adjacent animal cells or the transfer of small molecules and ions.
Sodium-potassium pump
The sodium-potassium pump is a channel protein that ushers out sodium ions and brings in potassium ions across the cell membrane, and depend on ATP to get ions across. This pump is found in neurons and skeletal muscle fibers.
Chitin
Chitin is a long polymer of a glucose derivative that is a principle component of the cell wall in fungi and of an arthropod's exoskeleton.
Active site
The active site is a region on the enzyme where the substrate binds.
Microfilaments
Microfilaments are thin, rodlike structures composed of the protein actin and are involved in cell mobility and muscle contraction.
Bioenergetics
Bioenergetics is the study of how cells release the energy stored in chemical bonds holding molecules together.
Enzyme-substrate complex
An enzyme-substrate complex is the term for the enzyme and substrate(s) bound together.
Induced fit
Induced fit refers to when an enzyme has to change its shape slightly to accommodate the shape of the substrates.
Solutes
A solute is a substance that is dissolved in a solvent.
Dialysis
Dialysis is the diffusion of solutes across a selectively permeable membrane.
Vesicles
Vesicles are little membrane sacs which carry materials around and out of the cell.
Golgi bodies
Golgi bodies , which look like stacks of flatten sacs, are organelles that participate in the processing of proteins in the cell. After the rough ER completes the synthesis of proteins, the Golgi bodies modify, process, ad sort the products. They then package and distribute the proteins to be sent out of the cell, packaging the products into vesicles.
Phagocytosis
Phagocytosis is endocytosis during which the cell takes in solids.
Tight junctions
Tight junctions are tight connections between the membrane of adjacent animal cells. They're so tight that there is no space between the cells, so they seal off body cavities and prevent leaks.
Active transport
Active transport is the movement of a substance against the concentration gradient, which required energy.
Bulk flow
Bulk flow is the one way movement of fluids brought about by pressure, such as the movement of blood through a blood vessel or fluids in xylem and phloem of plants.
Substrates
Substrates are the molecules targeted by an enzyme in an enzymatic reaction
Desmosomes
Desmosomes hold adjacent animal cells tightly to each other and consist of a pair of discs associated with the plasma membrane of adjacent cells. Intermediate filaments within and outside the cells are attached to the discs.
Enzymes
Enzymes are organic catalysts, molecules that speed up the rate of a reaction without altering the reaction itself.
Facilitated transport
Facilitated transport is the movement of lipid insoluble substances across the plasma membrane through special channel proteins.
Euglena
Euglena is a single celled flagellate in the protist kingdom.
Lysosomes
Lysosomes are organelles that carry digestive enzymes, which they use to break down old, worn out organelles, debris, or large ingested particles. The lysosomes help keep the cytoplasm clear of unwanted materials. Lysosomes contain hydrolytic enzymes that function at acidic pH, which is enclosed inside the lumen of the lysosome.
Cell sap
Cell sap is contained in the vacuole of mature plants and is a dilute fluid consisting of water, salts, glucose, and amino acids. Cell sap allows for storage and mechanical support in plants, especially non-woody plants.
Cilia
Cilia are threadlike structures made out of microtubules that provide locomotive properties in single-celled organisms.
Choloroplasts
Chloroplasts are organelles involved in photosynthesis that are possessed by plants. Chloroplasts contain chlorophyll, a light capturing pigment that gives plants their green color.
Activation energy
Activation energy is the energy needed to begin a chemical reaction.
Centrioles
Centrioles are small, paired cylindrical structures found within microtubule organizing centers. Centrioles are most active during cellular division, during which they produce microtubules, which pull apart the replicated chromosomes. Centrioles are not found in plant cells.
Ribosomes
Ribosomes are organelles that are the sites of protein synthesis - they manufacture all the proteins required by the cell or secreted by the cell. Ribosomes are round structures composed of RNA and proteins and can be either free floating or attached to the endoplasmic reticulum.
Endocytosis
Endocytosis is a means of a cell engulfing a substance too large to enter the cell. Endocytosis involves the cell membrane forming a pocket, pinching in, and forming either a vacuole or a vesicle.
Cell wall
A cell wall is a rigid layer just outside of the plasma membrane that provides support for the cell. It is found in plants, protists, bacteria, (made out of cellulose), and fungi (made out of chitin).
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Krebs cycle (citric acid cycle)
The Krebs Cycle, also known as the citric acid cycle, takes place in the matrix of the mitochondria. In the Krebs Cycle, each of the two acetyl coenzyme A molecules enter the cycle and combine with oxaloacetate to form citric acid, which then loses two carbons as carbon dioxide. The cycle is now ready to begin again with the second Acetyl CoA. For each Acetyl CoA, the Krebs Cycle produces 1 ATP, 3 NADH, and 1 FADH2.
Fermentation
Fermentation is the process of ATP production under anaerobic conditions. In this process, after glycolysis pyruvic acid is converted to either lactic acid or ethyl alcohol and carbon dioxide. This process also produced NAD+, which allows glycolysis to continue. This process is not very efficient, and only results in a gain of 2 ATP for each molecule of glucose broken down.
Aerobic respiration
When ATP is made in the presence of oxygen, the process is called aerobic respiration. Aerobic respiration consists of four stages: Glycolysis, formation of acetyl CoA, the Krebs cycle, and oxidative phosphorylation.
Competitive inhibition
Competitive inhibition is a process by which a chemical substance has a shape that fits the active site of an enzyme and competes with the substrate, effectively inhibiting the enzyme.
Oxidative phosphorylation
Oxidative phosphorylation refers to the process by which ATP synthase uses the flow of protons into the matrix to combine ADP and P, producing ATP. Oxidative phosphorylation produces 32 ATP.
Cytochromes
Cytochromes are iron-containing carriers that are carrier molecules in the electron transport chain. These carrier molecules hand down electrons to the end of the chain, where they are accepted by oxygen molecules. This system releases energy which is used to pump hydrogens across the inner membrane, setting up a proton gradient responsible for the production of ATP.
Lymph node
A lymph node is a mass of tissue found along the course of a lymph vessel that contains a large number of lymphocytes, white blood cells that attack foreign pathogens.
Inter-membrane space
The inter-membrane space is the space between the inner and outer mitochondrial membrane. In cellular respiration, hydrogen atoms are pumped across the inner mitochondrial membrane into the inter-membrane space, creating a proton gradient that is responsible for the production of ATP.
Cytotoxic T-cells
Cytotoxic T-cells are a type of T-cells that recognize and kill infected cells.
Matrix
The matrix is the inner region of the mitochondria, inside the inner membrane. The citric acid cycle, or Krebs cycle, takes place inside the matrix of the mitochondria.
Cell-mediated immunity
Cell-mediated immunity is an immune response that does not involve antibodies, but rather involves the activation of phagocytes, cytotoxic T-cells, and various cytokines.
Major histocompatibility complex
The MHC is a set of cell surface proteins essential for acquired immune system to recognize foreign cells.
Oxaloacetate
Oxaloacetate is a four carbon molecule that combines with Acetyl CoA in the Krebs Cycle to form citric acid. This citric acid then loses two carbons as carbon dioxide, to form oxaloacetate again, so that the Krebs cycle can begin again.
Inner mitochondrial membrane
The inner mitochondrial membrane is the innermost membrane of the mitochondria. Oxidative phosphorylation and chemiosmosis take place at the inner mitochondrial membrane, which produces ATP via the flow of protons across the membrane.
ATP synthase
The ATP synthase is a channel on the inner mitochondrial membrane. Protons diffuse through the ATP synthase channel, moving into the matrix of the mitochondria. The ATP synthase uses the energy from this diffusion to combine ADP and P on the matrix side of the channel, creating ATP, a process known as oxidative phosphorylation. The total number of ATP produced by oxidative phosphorylation is 32 ATP.
Feedback inhibition
Feedback inhibition is a system in which the formation of an end product inhibits an earlier reaction in the enzymatic sequence.
First law of thermodynamics
The first law of thermodynamics states that energy cannot be created or destroyed.
Pyruvic acid
Pyruvic acid is a 3 carbon molecule produced by the splitting of a glucose in glycolysis. Pyruvate is important because it goes on to be broken down into acetyl CoA.
Allosteric activator
Allosteric activators bind to an enzyme and induce its active form.
Lymphatic system
The lymphatic system is a system in the body made up of a network of vessels that conduct lymph. The lymphatic system has three functions: to collect, filter, and return fluid to the blood by the contraction of adjacent muscles, to fight infection using lymphocytes, and to remove excess fluid from body tissue.
Glycolysis
Glycolysis, the splitting of glucose, is the first step in aerobic respiration. During glycolysis glucose, a 6-carbon molecule, is broken into two three carbon molecules called pyruvic acid. This breakdown of glucose also results in the net production of two molecules of ATP.
pH gradient (proton gradient)
The energy released from the electron transport chain is used to pump hydrogen ions across the inner mitochondrial membrane to the inter-membrane space. The pumping of hydrogen ions into the inter-membrane space creates a pH gradient, in which the inter-membrane space has a high hydrogen concentration and the matrix has a low hydrogen concentration. This gradient establishes the potential energy responsible for the production of ATP, as hydrogen molecules diffuse through the ATP synthase.
Memory T-cells
Once activated, T cells multiply and give rise to clone cells, some of which become memory T-cells. Memory T-cells recognize pathogen they have encountered before, allowing for a quicker immune response in a second exposure.
Lymph
Lymph is a clear, watery fluid formed from interstitial fluid that runs in networks of vessels as part of the lymphatic system. Lymph contains white blood cells that attack bacteria in the blood.
Entropy
Entropy is disorder, and is what the universe tends towards.
Acetyl coenzyme A
When oxygen is present, pyruvic acid is transported to the mitochondrion, where each pyruvic acid is converted into acetyl coenzyme A, a two carbon molecule. Two Acetyl CoA are produced from two pyruvic acid. Acetyl CoA then moves to the Krebs Cycle, where it combines with oxaloacetate to form citric acid.
Antigen
An antigen is a substance that causes an immune system to produce antibodies against it. These include foreign molecules such as viruses, bacteria, or chemicals.
Interferons
Interferons are a group of signaling proteins released by host cells in response to a pathogen. They inhibit viral replication and activate surrounding cells that have antiviral actions.
Cellular respiration
Cellular respiration is a process performed by all organisms that produced ATP through the breakdown of nutrients. In cellular respiration, a sugar is combined with oxygen and water to produce carbon dioxide, water, and energy in the form of ATP.
Allosteric regulators
Allosteric regulators are substances that can either inhibit or activate enzymes and that bind at the allosteric site.
Helper T-cells
Helper T-cells activate B-lymphocytes and other T-cells in responding to the infected cells.
AIDS
AIDS, or acquired immunodeficiency syndrome, is a devastating disease that interferes with the body's immune system. AIDS is caused by the infection of helper T cells by HIV, which destroys the T cells and prevents the body from defending itself.
Pathogen
A pathogen is a disease-causing agent that activates an immune response in the body.
Lactic acid
Lactic acid is a by-product of fermentation. Two lactic acid molecules are produced for every one glucose that is broken down. Lactic acid is produced by some bacteria during anaerobic respiration and by muscles when they do not get enough oxygen.
Complement proteins
Complement proteins are proteins that lyse the cell wall of an antigen. They are part of the nonspecific defense mechanisms of the immune system.
MHC markers
In the MHC system, MHC molecules bind to peptide fragment from foreign pathogens and display them on the cell surface for recognition by T cells.
Outer membrane
The outer membrane is the outermost membrane in the mitochondria that protects and holds the form of the organelle.
Second law of thermodynamics
The second law of thermodynamics states that energy transfer leads to less organization and the universe tends towards disorder (entropy).
Allosteric inhibitor
Allosteric inhibitors bind to an allosteric site and keep the enzyme in its inactive form.
Inflammatory response
Inflammatory response is a defense mechanism of the immune system in which damaged or infected cells release chemicals such as histamine, which causes inflammation. Inflammation allows for increased blood flow to the area, strengthening the immune response.
Cofactors
Cofactors are inorganic elements that help catalyze reactions and are usually metal ions.
Immune system
The immune system is one of the body's defense systems - a carefully coordinated system of specialized cells to protect the body from foreign threats.
Lymphocytes
Lymphocytes are small white blood cells present in the lymphatic system that fight infection. They multiple rapidly when they come in contact with a foreign substance.
Photosynthesis
Photosynthesis is a process that involves the transformation of solar energy into chemical energy. Plants take carbon dioxide, water, and energy (in the form of sunlight) and use them to produce glucose.
Phagocytes
A phagocyte is a type of cell that is part of the body's defense mechanism. They are cells that are capable of engulfing and eventually destroying antigens.
Citric acid
Citric acid, or citrate, is a six carbon molecule formed in the Krebs cycle by the joining of an Acetyl CoA molecule with an oxaloacetate. Citric acid then loses two carbons, in the form of carbon dioxide, to become oxaloacetate again.
Anaerobic respiration
When ATP is made without oxygen, the process is called anaerobic respiration.
Ethyl alcohol (ethanol)
Ethyl alcohol is a by-product of fermentation. Two ethyl alcohol molecules are produced for every one glucose that is broken down. Yeast cells and some bacteria make ethanol and carbon dioxide during anaerobic respiration.
Allosteric sites
An allosteric site is a region of the enzyme other than the active site to which a substance can bind, and can regulate enzymatic activity.
Noncompetitive inhibition
In noncompetitive inhibition, the inhibitor binds with the enzyme at a site other than the active site and inactivates the enzyme by altering its shape.
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Ecdysone
Ecdysone is a hormone that is promotes molting and the metamorphosis of a larva to a butterfly.
Depolarization
At the point where the axon connects to the cell body, gated sodium ion channels open up and allow sodium ions to rush into the cell, making the inside of the cell more positive than the outside, a change known as depolarization.
Neurons
Neurons are specialized cells in the nervous system that transmit nerve signals. A neuron consists of a cell body, dendrites, and an axon. The three types of neurons are sensory neurons, motor neurons, and interneurons.
Action potential
Action potential is a change in the membrane potential that produces a nerve impulse. Action potential is an all-or-none response; it doesn't fire "part way," and generally must reach -55mV to produce a response.
Brain hormone
Brain hormone is an insect hormone that targets ecdysone to be released in the prothoracic glands.
Somatic nervous system
The somatic nervous system is the part of the peripheral nervous system that controls voluntary activities.
Refractory period
The refractory period is the period after an action potential. During this period, sodium channels are reset and are able to open, but the cell membrane potential is further from the threshold and a great stimulus is required to reach the threshold.
Central nervous system
The central nervous system includes all of the neurons within the brain and spinal cord.
Repolarized
Once sodium ions have flooded the neuron, the sodium channels close. At this point, the potassium channels open and the potassium ions rush out of the axon, and the electrical changes reverse again, so it is negative on the inside, and positive on the outside. Once the charges are restores, the section of the neuron is said to be repolarized.
Autonomic nervous system
The autonomic nervous system is the part of the peripheral nervous system that controls involuntary activities, such as the digestive system or heartbeats.
Threshold
The threshold is the minimum amount of stimulus a neuron needs to respond.
Midbrain
The midbrain is the center for visual and auditory reflexes (pupil reflex and blinking).
Acetylecholine
Acetylcholine is an important neurotransmitter that is released from the end of an axon when calcium ions move into the terminal end of the axon. Acetylcholine is picked up almost instantly by the dendrites of the the next neuron. It can stimulate muscles to contract or inhibit postsynaptic potential. Acetylcholine is released between neurons in the parasympathetic system.
Parasympathetic nervous system
Parasympathetic nervous system is a part of the autonomic system that works antagonistically to the sympathetic nervous system, returning the body to homeostasis after a stress response.
Neurotransmitter
A neurotransmitter is a chemical released by an axon into the space between the two neuron, called the synapse. The neurotransmitter diffuses across the synaptic cleft and binds to receptors on the dendrites of the next neuron, usually triggering an action potential.
Corpus callosum
The corpus callosum is a thick band of nerve fibers of the white matter that enable the right and left side of the cerebral hemispheres to communicate.
Hypothalamus
The hypothalamus is the part of the brain that regulate homeostasis, secretes hormones, and regulates the pituitary gland.
T-lymphocytes
T-lymphocytes are cells that fight infection and help the B-lymphocytes proliferate.
Synapse
The synapse is the space between two neurons where the neurotransmitter is diffused across.
Interneurons
Interneurons are links between sensory neurons and motor neurons, found in the brain or spinal cord.
Homeostasis
Homeostasis refers to the stable conditions of your body, including steady heart and respiratory rates. The parasympathetic system works to keep the body at homeostasis.
GABA
GABA is an important neurotransmitter that is secreted in the central nervous system and acts as an inhibitor.
Medulla
The medulla is the part of the brain that controls involuntary actions such as breathing, swallowing heartbeat, and respiration.
Myelin sheath
Myelin sheath is a substance produced by Schwann cells surrounding a neuron. Myelin sheath insulates the neuron and allows for a quicker propagation of an impulse, since the impulse can now jump from node to node.
Thalamus
The thalamus is the main sensory relay center for conducting information between the spinal cord and cerebrum.
Ganglia
Ganglia are clumps of nerve cells similar to primitive brains that develop in animals that are more complex.
Polarized
In a resting neuron cell, there is a potential difference between the inside and the outside of the cell. The resting membrane potential is always negative inside the cell, with a -70 mV charge. This polarized cell is the result of Na-K-ATPase pumps that pump 2 potassium ions into the cell and 3 sodium ions out of the cell.
Axon bulb
The axon bulb is the area at the end of the axon, where signal transmission to the next neutron occurs.
Norepinephrine
Norepinephrine is an important neurotransmitter that is released between neurons within the central nervous system.
Acetylcholinesterase
Acetylcholinesterase is an enzyme that breaks down extra acetylcholine in the synaptic cleft.
Sensory neurons
Sensory neurons receive impulses from the environment and bring them to the body. For example, they can be stimulated by touch.
Cerebrum
The cerebrum is a part of the brain that controls all voluntary activities and receives and interprets sensory information. It is the largest part of the brain and consists of outer gray matter (cerebral cortex) and inner white matter.
Nodes of Ranvier
The Nodes of Ranvier are the spaces between myelin sheaths - the exposed regions of the axon.
Sodium-potassium pump
After a part of the neuron has been repolarized, the charges are in their original state, but the ions are on the wrong side of the axonal membrane, with potassium outside and sodium inside. The neuron reestablishes the order of the ions with the sodium-potassium pump, which pumps two potassium ions inside the axon for every three sodium ions it pumps out.
Peripheral nervous system
The peripheral nervous system includes al neurons lying outside the brain and the spinal cord - in our skin, our organs, and our blood vessels.
Nerve net
The nerve net is a system made up of a network of nerve cells, the impulse of which travels in both directions. The nerve net is the simplest nervous system found in simple animals such as hydra.
Endocrine glands
Endocrine glands are specialized organs that secrete hormones in to the bloodstream, where they are carried throughout the body.
Axon
The axon is a long, slender extension that transmits an impulse from the cel body to another neuron or to an organ.
Hormones
Hormones are chemicals that are produced in one region of the body to act on target cells in another region. Hormones are produced in endocrine glands. Hormones have a number of functions including regulating growth, behavior, development, and reproduction.
Cerebral cortex
The cerebral cortex is outer gray matter of the cerebrum that plays an important role in consciousness.
Motor (effector) neurons
Motor neurons transmit the impulse to muscles or glands to produce a response. The muscle will respond by contracting, or the gland will respond by secreting a substance.
Cerebellum
The cerebellum is a part of the brain that coordinates muscle activity and refinement of movement.
Schwann cells
Schwann cells are cells that wrap around the neuron and produce a substance called the myelin sheath, which insulates the axon.
Sympathetic nervous system
The sympathetic nervous system is a part of the autonomic system that controls the "flight-or-fight" response in organisms.
Saltatory conduction
Saltatory conduction is the form of conduction of an impulse involving myelin sheaths. In this form the impulse can jump form node to node, instead of the standard "domino effect," therefore speeding up the impulse.
Dendrites
Dendrites are short extensions of the cell body that receive stimuli.
Cell body
The cell body is a part of a neuron that contains the nucleus and other organelles found in the cytoplasm.
B-lymphocytes
B-lymphocytes are cells that mature in the bone marrow and are involved in the humoral response, which defends the body against pathogens present in extracellular fluids. B cells produce antibodies that bind to the antigens on the surface of pathogens.
"Flight-or-fight" response
The flight-or-fight response is a response that occurs when an organism confronted with a threatening situation prepares to fight or flee. This response is controlled by the sympathetic system. This response includes rising heart and respiration rates, constriction of blood vessels, increase in the levels of glucose in your body, and "goose bumps" on your skin.
Pons
The pons connects parts of the brain with one another and contains respiratory center.
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Anterior pituitary
The anterior pituitary is a part of the pituitary gland that secretes six hormones, three of which regulate growth and other organs and three of which are involved in regulating the reproductive system. The hormones of the anterior pituitary are growth hormone, adrenocorticotropic hormone, thyroid-stimulating hormone, follicle-stimulating hormone, luteinizing hormone, and prolactin.
Parathyroid hormone
Parathyroid hormone is released by parathyroids and it increases blood calcium levels if the blood needs more calcium. Thus, the parathyroid hormone has the opposite effect as calcitonin.
Follicular phase
The follicular phase is a phase in the menstrual cycle during which FSH stimulates the growth of follicles in the ovary, one of which will dominate the others and eventually be the only one growing. During this phase, the growing follicle releases estrogen, which leads to a surge of LH, which triggers ovulation, making the follicle burst and release the ovum into the fallopian tube. The follicular phase also involves the thickening of the uterine walls in preparation for the implantation of a fertilized cell. This entire phase lasts about 10 days.
Pituitary
The pituitary land is called the master gland because it releases many hormones that reach other glands and stimulate them to release their own hormones. The pituitary gland has two parts: the anterior pituitary and the posterior pituitary.
Glycogen
Glycogen is a multi-branched polysaccharide of glucose that serves as an energy store. Glycogen is stored in the liver and can easily be converted to glucose. Glucagon stimulates an increase of glycogen into glucose while insulin stimulates an increase of glucose into glycogen.
Estrogen
Estrogen is a sex hormone that is released by the ovaries that regulate the menstrual cycle.
Puberty
Puberty is the process of physical changes through which a child's body matures into an adult body capable of sexual reproduction. In males, testosterone and cortical sex hormones, is responsible for the development of the voice and secondary sex characteristics, such as the deepening of the voice, facial and body hair, and muscle growth.
Hypothyroidism
Hypothyroidism is a condition that occurs in individuals who have too little thyroxine circulating in their bloodstream. They exhibit a slow metabolic rate and tend to be sluggish and overweight.
Sperm cells
Sperm cells are produced by the testes when they are stimulated by testosterone.
Target cells
Target cells are the specific cells that a hormone effects.
Ova
Ova are egg cells that are manufactured in the ovaries. During menstruation, an ovum is released from the ovaries and travels to the fallopian tubes, where it may be fertilized.
Human chorionic gonadotropin (HCG)
Human chorionic gonadotropin is a hormone produced by an embryo following implantation. The hormone helps maintain the uteral lining during pregnancy. The presence of HCG is detected in pregnancy tests.
Amine
Hormones that are amines cannot get into a cell by simple diffusion, and must bind to a receptor protein on the cell membrane of the target cell.
Pheromones
Pheromones are hormones that help animals to communicate with members of their species and attract the opposite sex.
Ovulation
Ovulation refers to the release of the follicle from the ovary and is triggered by the hormone luteinizing hormone. After being released, the ovum travels into the fallopian tubes.
Epinephrine
Epinephrine is a hormone produced by the adrenal medulla. Together with norepinephrine, epinephrine is responsible for the "fight-or-flight" response. Epinephrine increases heart rate, metabolic rate, and blood pressure.
Hypothalamus
The hypothalamus is a part of the brain that works closely with the pituitary, regulating the anterior pituitary by secreting neurohormones that can stimulate or inhibit the actions of the anterior pituitary.
Glucocorticoids
Glucocorticoids are hormones produced in the adrenal cortex that increase the blood's concentration of glucose and help the body adapt to stress. It does this by promoting the conversion of amino acids and fatty acids to glucose.
Follicle-stimulating hormone (FSH)
Follicle-stimulating hormone is a hormone secreted by the anterior pituitary that stimulates follicles in the ovaries to grow.
Growth hormone (GH)
Growth hormone is a hormone produced in the anterior pituitary that stimulates growth throughout the body, targeting bones and muscles.
Thyroid-stimulating hormone (TSH)
Thyroid-stimulating hormone is a hormone produced in the anterior pituitary that stimulates the thyroid to secrete thyroxine, which is responsible for the regulation of metabolism.
Parathyroids
The parathyroids are four little pea-shaped organs that rest on the thyroid. They secrete parathyroid hormone, which increases blood calcium levels.
Insulin (beta cell)
Insulin is a hormone secreted by the pancreas, where it is made by beta cells. Insulin targets the liver and muscle cells and has the opposite effect that glucagon does; insulin stimulates the liver to convert glucose into glycogen, lowering the blood sugar level.
Hyperthyroidism
Hyperthyroidism is a condition that occurs in individuals who regularly release too much thyroxine. These people have a fast metabolic rate and tend to be irritable and nervous.
Luteinizing hormone (LH)
Luteinizing hormone is a hormone produced in the anterior pituitary that causes the release oft he ovum during the menstrual cycle in females, and testosterone production in males.
Corpus luteum
During the luteal phase of menstruation, the ruptured follicle condenses into a little yellow blob called the corpus luteum, which is Latin for "yellow body." The corpus luteum secretes estrogen and progesterone, to promote the growth of glands and blood vessels in the endometrium to ready the body for pregnancy. Progesterone is important because without it the fertilized ovum cannot latch onto the uterus and develop into an embryo.
Oxytocin
Oxytocin is a hormone secreted by the posterior pituitary that stimulates contraction of uterus and ducts of mammary glands. This hormone is made in the hypothalamus, but stored in the posterior pituitary.
Glucagon (alpha cell)
Glucagon is a hormone secreted by the pancreas. Glucagon is produced by alpha cells and stimulates the liver to convert glycogen into glucose and to release that glucose into the blood. Glucagon therefore increases the levels of glucose in the blood, raising the blood sugar level.
Menstruation
Menstruation, or the flow phase, is a phase of the menstrual cycle that occurs after the corpus luteum has turned off. During this phase the uterus starts to reabsorb the tissue that the progesterone encouraged it to grow. Some of the tissue cannot be reabsorbed and is shed, through bleeding.
Fallopian tube
The fallopian tubes are a part of the female reproductive system to which the ovum travels during ovulation and are the site of fertilization. They are also known as oviducts.
Thyroxine
Thyroxine is a hormone secreted by the thyroid that contain iodine and is responsible for regulating metabolic rates in body tissue.
Juvenile hormone
Juvenile hormone is a hormone that causes larvae to retain their characteristics; the concentration of this hormone decreases as the larva undergoes metamorphosis.
Adrenal cortex
The adrenal cortex is an endocrine gland that is part of the adrenal glands. The adrenal cortex is targeted by adrenocorticotropic hormone (ACTH), which stimulates the adrenal cortex to produce and secrete its different hormones. The adrenal cortex releases two types of hormones: glucocorticoids, to lower blood sugar, and mineralocorticoids, to help the body retain sodium and water in the kidneys.
Calcitonin
Calcitonin is a hormone secretes by the thyroid. This hormone decreases blood concentration of calcium by concentrating free-floating calcium in the bones.
Adrenocorticotropic hormone (ACTH)
Adrenocorticotropic hormone is a hormone produced in the anterior pituitary that stimulates the adrenal cortex to secrete glucocorticoids and mineralocorticoids.
Posterior pituitary
The posterior pituitary is a part of the pituitary gland that secretes two hormones: antidiuretic hormone and oxytocin.
Antidiuretic hormone (vasopressin)
Antidiuretic hormone is a hormone secreted by the posterior pituitary that regulates water intake by nephrons in the kidney. This hormone is made in the hypothalamus, but stored in the posterior pituitary.
Cyclic AMP (cAMP)
When a hormone binds to a receptor protein on the cell membrane of a target cell, the protein stimulates the production of a second messenger called cyclic AMP. The cAMP molecule then triggers various enzymes, leading to a specific cellular change.
Prolactin
Prolactin is a hormone produce in the anterior pituitary that stimulates the mammary glands to produce milk.
Progesterone
Progesterone is a sex hormone that is released by the ovaries that regulate the menstrual cycle.
Uterine wall/ Endometrium
The uterine wall, or endometrium, is the inner mucous membrane of the mammalian uterus. During the follicular phase of the menstrual cycle the endometrium thickens in preparation for the implantation of a fertilized cell. In the luteal phase of the menstrual cycle, progesterone promotes the growth of glands and blood vessels in the endometrium in preparation for pregnancy. If the egg is not fertilized, some of the tissue that the progesterone encouraged to grow on the uterine wall is shed and bled out.
Negative feedback system (hormones)
Hormones operate by a negative feedback system. That is, an excess of the hormone will signal the endocrine gland to temporarily shut down production.
Follicle-stimulating hormone (FSH)
Follicle-stimulating hormone is a hormone produced in the anterior pituitary that stimulates the follicle to grow in females, and spermatogenesis in males.
Bone remodeling
Bone remodeling refers to the process of building or breaking down bones to store and release calcium and involves the parathyroid hormone and calcitonin.
Testosterone
Testosterone is a male sex hormone responsible for promoting spermatogenesis. Testosterone also maintains secondary sex characteristics.
Mineralocorticoids
Mineralocorticoids are hormones produced by the adrenal cortex that help the body retain sodium and water in the kidneys. They accomplish this by promoting the reabsorption of sodium and chlorine, which together from common salt. When salt is absorbed, so it water.
Islets of Langerhans
The islets of Langerhans are clusters of cells in the pancreas that produce insulin and glucagon. The alpha cells produce glucagon and the beta cells produce insulin.
Thyroid gland
The thyroid gland, which is located in the neck, is the target organ of the thyroid-stimulating hormone (TSH). When the thyroid is stimulated by TSH, it releases the hormone thyroxine, which is responsible for regulating the metabolic rates in body tissue.
Luteal Phase
Luteal stage During the luteal stage, the ovum has moved into the fallopian tube and the follicle has been ruptured and left behind in the ovary. The ruptured follicle (now a fluid filled sac) continues to function in the menstrual cycle, condensing into a little yellow blob called the corpus luteum. The corpus luteum continues to secrete estrogen and begins to produce progesterone, which gets the body ready for pregnancy by promoting the growth of glands and blood vessels in the endometrial. This stage lasts about 13 to 15 days, until the corpus luteum shuts down.
Luteinizing hormone (LH)
Luteinizing hormone is a hormone secreted by the anterior pituitary in response to an increase in estrogen released by the follicle in the ovary. An increase in estrogen causes a sudden surge in LH which triggers ovulation - the release of the follicle from the ovary.
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Directional selection
In directional selection, one phenotype is favored at one of the extremes of normal distribution.
Neurula
The neurula stage of embryo development begins with the formation of the notochord and the neural tube cells, which are part of the development of a nervous system.
Umbilical chord
The umbilical chord is an organ that is an outgrowth of extra-embryonic membranes in placental mammals and connects the embryo to the placenta.
Gastrulation
During gastrulation, the zygote begins to change its shape. Cells now migrate into the blastocoel and differentiate to form three germ layers: the ectoderm (outer layer), mesoderm (middle layer), and endoderm (inner layer). The ectoderm produces the epidermis, eyes, and the nervous system. The endoderm produces the inner linings of the digestive and respiratory tract as well as accessory organs such as the pancreas, gall bladder, and liver. The mesoderm gives rise to everything else, including bones and muscles.
Embryo
An embryo is an organism in the early stages of development, and is used to describe an unborn baby up until the 8th week, at which point it is referred to as a fetus. Immediately after fertilization, the zygote undergoes rapid division and becomes a recognizable embryo at around 4 weeks.
Jean Baptiste de Lamarck
Jean-Baptiste de Lamarck was an 18th century scientist who proposed a theory explaining the variety of life on Earth. Lamarck believed that acquired traits were inherited and passed on to offspring, a theory referred to as the "law of use and disuse." This theory was very popular in Darwin's day, although we now know it to be wrong.
Blastocoel
The blasocoel is the fluid filled cavity inside a blastula.
Yolk sac
The yolk sac is an extra-embryonic membrane that provides food for the embryo.
Hox genes
Hox genes are a subset of homeobox genes that specify the position of body parts in the developing embryo.
Chorion
The chorion is the outermost extra-embryonic membrane that surrounds all the other extra-embryonic membranes.
Seminiferous tubules
Seminiferous tubes are the main tissues of the testes and are where spermatogonia undergo meiosis.
Stabilizing selection
In stabilizing selection, organisms in a population with extreme traits are eliminated, favoring organisms with common traits. An example is birth weight in humans; abnormally small or large babies have a lower chance of surviving both and infancy.
Morula
After a number of cell divisions, the fertilized egg (zygote) becomes a solid ball of cells called a morula.
Molecular biology
The similarities of organisms at the molecular level is compelling evidence of evolution. Scientists have observed that organisms that are closely related have a greater proportion of DNA sequence sin common than distantly related species.
Random mutation
Random mutations are the random changes in the genes of individuals, which allows for genetic variability and evolution to occur.
Homeobox genes
Homeobox genes are a type of homeotic gene that consists of homeoboxes (short, nearly identical DNA sequences) that encode proteins that bind to DNA; these proteins tell cells in various segments of the developing embryo what type of structures to make.
Prostate gland
While traveling through the vas deferens, sperm picks up fluids from the prostate gland which provides an alkaline fluid that neutralizes the vagina's acidic fluids.
Apoptosis
Apoptosis, or programmed cell death, plays a crucial role in normal differentiation and development. For example, in a human embryo, apoptosis allows for the removal of tissue between newly developing fingers and toes.
Genetic variability
The genetic differences in every individual is known as genetic variability. The survival of a species is dependent on genetic variation, since it allows a population to survive in a changing environment.
Allantois
The allantois is an extra-embryonic membrane that is involved in gas exchange and stores uric acid.
Homologous structures
Homologous structures are similar structures that serve different functions, such as a human's arm, a dog's leg, a bird's wing, and a whale's fin, which look similar but serve different purposes. Homologous structures point to a common ancestor and support evolution.
Extra-embryonic membranes
In addition to the primary germ layers, some animals, such as chickens, have extra-embryonic membranes. The four extra-embryonic membranes include: the yolk sac, amnion, chorion, and allantois. These extra membranes are common in birds and reptiles.
Fetus
After an embryo matures to about 4 weeks, it is referred to as a fetus.
Cleavage
Fertilization triggers the zygote to undergo a series of rapid cell divisions, by mitosis, called cleavage.
Neutral tube
The neural tube cells are cells formed during the neurula stage that develop into the central nervous system.
Blastula
As the cells in the morula continue to divide, they press against each other and produce a fluid filled cavity called a blastocoel.
Induction
Induction is the process in embryonic development by which the presence of one tissue determines the differentiation of another tissue.
Placenta
The placenta is an outgrowth of extra-embryonic membranes in placental mammals that is the organ that provides the fetus with nutrients and oxygen and gets rid of the fetus's waste. The placenta develops from both the chorion and the uterine tissue of the mother.
Morphogenesis
Morphogenesis is the process by which a single celled egg develops into a complex, multicellular organism.
Homeotic genes
Homeotic genes control the development of the embryo and include homeobox genes that tell cells in the developing embryo what type of structure to make.
Adaptation
An adaptation is a trait that improved an individuals fitness, and is favored by natural selection. These adaptions are likely to be passed on to the next generation.
Biogeography
Biogeography, or the study of the distribution of flora and fauna, have revealed a number of related species in widely separated regions of the world, supporting the theory of a common ancestor.
Embryology
Embryology is the study of the development of an organism. In the early stages of vertebrate development, all embryos look alike, supporting the theory of evolution.
Analogous structures
Analogous structures are animal features that have the same function but are structurally different, such as a bat's wing and an insect's wing. These strucutres evolved independently of one another.
Vas deferens
The vas deferens is the duct that conveys sperm from the testicle to the urethra.
Epididymis
The epididymis is a highly convoluted duct behind the testis, where the spermatids mature and then pass to the van deferens.
Organizers
Organizers are cells that release a chemical substance (a morphogen) that moves from one tissue to the target tissue. Organizers are involved in induction in embryonic development.
Differentiation
Differentiation is the process by which a less specialized cell becomes a more specialized cell type, through homeotic genes.
Seminal vesicles
While in the vas deferens, sperm picks up fluids from the seminal vesicles which provides them with fructose for energy.
Charles Darwin
Charles Darwin was a 19th century British naturalist who sailed the world in a ship named the HMS Beagle. Darwin developed his theory of evolution based on natural selection after studying animals in the Galapagos Islands, and his work forms the basis of what we know about evolution. In his book entitled "On the Origin of Species," Darwin observed the following: Each species produces more offspring than can survive; these offspring compete with one another for limited resources; organism in every population vary; the fittest offspring, those with the most favorable traits, are most likely to survive and pass on their traits.
Notochord
The notochord is a rod shaped structure running beneath the nerve cord that is formed during the neurula stage and is important in the development of the nervous system.
Natural selection
Natural selection is the driving force of evolution and refers to the differential survival and reproduction of individuals due to differences in phenotype and general fitness.
Zygote
When an egg is fertilized by a sperm, it forms a diploid cell called a zygote. A zygote has 46 chromosomes, while the egg and sperm have 23 each.
Morphogen
Morphogen is a chemical substance released by organizer cells that moves form one tissue to the target tissue, helping with induction in a developing embryo.
Amnion
The amnion is an extra-embryonic membrane that forms a fluid-filled sac that protects the embryo.
Comparative anatomy
Comparative anatomy is the study of the anatomy of various animals and has revealed similar structures in a wide variety of animals, supporting the theory of evolution.
Fertilization
For fertilization to occur, the sperm must dissolve the corona radiata, a dense covering of follicle cells that surrounds the egg. Then the sperm must penetrate the zona pellucida, the zone below the corona radiata. When the egg is fertilized it forms a diploid cell called a zygote and undergoes a series of rapid cell division.
Paleontology
Paleontology, or the study of fossils, has revealed the great variety of organisms (most of which have died off) and the major lines of evolution.
Interstitial cells
Interstitial cells are supporting tissue in the testis that produce testosterone and other androgens.
Evolution
Evolution is the process by which living organisms change over time as a result of changes in heritable physical or behavioral traits. Evidence for evolution includes: paleontology, biogeography, embryology, molecular biology, and comparative anatomy.
Section 39
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Associative learning
Food chain
Carbon cycle
Learning
Learning is a form of behavior that refers to a change in a behavior brought about y an experience.
Phototropism
Speciation
Speciation refers to the emergence of anew species by evolution.
Community
Photperiodism
Imprinting
Behavior
Behavior is the way that organisms cope with their environments. Some animals behave in a programmed way to specific stimuli, while other behave according to some type of learning. The general types of behavior are: instinct, imprinting, classical conditioning, operant conditioning, and insight.
Secondary consumers
Gravitropism
Divergent evolution
Divergent evolution is the evolution of a new species from a current population, often as a result of geographic division.
Hardy-Weinberg law
The Hardy-Weinberg law states that even with all the shuffling of genes that goes on, the relative frequencies of genotypes in a population still prevail over time; the dominant gene doesn't become more prevalent and the recessive gene doesn't disappear. The Hardy-Weinberg law only applies if a population meets five conditions: large population, no mutations, no immigration or emigration, random mating, and no natural selection.
Agnostic behavior
Ecosystem
Reasoning
Biosphere
Niche
Operant conditionaing
Herbivores
Species
A species is a group of organisms having many physical and behavior characteristics in common and are able to interbreed to produce fertile and viable offspring.
Mutualism
Circadian rythyms
Thigmotropism
Tertiary consumers
Territoriality
10% rule
Genetic drift
Genetic drift is a phenomenon that occurs in small population during which a gene pool will change over time by random chance. Genetic drift often occurs with the founder effect, when a small group of organisms moved to a new location, or the bottleneck effect, when a populations size is greatly and randomly reduced. Genetic drift is a violation of the Hardy-Weinberg law.
Sympatric speciation
Sympatric speciation refers to speciation that does not involve geographic barriers, and is common in plants.
Pre-zygotic barriers
Pre-zygotic barriers are barriers that prevent fertilization, which could be geographic or behavioral differences, such as if two species reproduce at different times of the year, which is known as temporal isolation.
Ecological pyramid
Altruistic behavior
Tropism
Habituation
Population
Insight
Ecology
Ecology is the study of the interactions between living things and their environments.
Classical conditioning
Biomes
Phermomoness
Primary consumers
Disruptive selection
In disruptive selection, extreme traits are favored and natural selection works against common traits. For example, in elephant seals, females are selected to be small and males are selected to be large.
Fixed action pattern
A fixed action pattern is a particular type of innate behavior that is not a simple reflex, but no a conscious decision. An example is the egg-rolling behavior exhibited by the graylag goose. If the egg is removed form the goose, it will continue to make the same movement.
Convergent evolution
Convergent evolution is the process by which two unrelated and dissimilar species come to have similar (analogous) traits, often because they have been exposed to similar selective pressures.
Allopatric speciation
Allopatric speciation refers to speciation when part of a population is physically separated from the rest by a geographic barrier and therefore they cannot interbreed.
Instinct
Instinct is an inborn, unlearned behavior. Sometimes instinctive behavior is triggered by environmental signals called releasers - a small part of the environment that is perceived.
Post-zygotic barriers
Post-zygotic barriers are barriers related to the inability of the hybrid to produce offspring, such as the sterile mule.
Critical period
Dominance hierarchy
Section 40
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