Section 1
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Give examples of how buffers maintain a stable environment in an animal's body fluids.
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Section 1
(50 cards)
Give examples of how buffers maintain a stable environment in an animal's body fluids.
buffers resist changes in pH by accepting H ions when they are in excess and donating H ions when they have been depleted. One example of a buffer system in the human body is blood (between H2CO3 and HCO3-)
Explain how a single element may exist in more than one form, called isotopes, and how certain isotopes have importance in human medicine.
Isotopes are atoms of the same element that have different numbers of neutrons. Radioactive isotopes can be used in medicine as tracers to trace the spread of cancer through the body.
Compare and contrast the different types of isomeric compounds.
isomers are compounds that have the same number of atoms but different structures. structural isomers differ in the covalent arrangement of their atoms. cis-trans isomers differ in their spacial arrangements due to the inflexibility of double bonds. enantiomers are isomers that are mirror images of each other and that differ in shape due to the presence of a chiral carbon
Explain the properties of carbon that make it the chemical basis of all life.
- it has 4 valence electrons so it can bond to various other atoms - it can also bond to other carbon atoms, forming the carbon skeletons of organic compounds, which can vary in length and shape and have bonding sites for other elements - it is abundant
Explain how cells form boundaries. Discuss how the proteome influences the composition and structure of cellular compartments and how this may differ in two cells of the same organism, or how it might differ in the same cell under different conditions.
proteomes are the part of the gene that codes for proteins
Understand the general structure of atoms and their constituent particles
an atom is the smallest unit of an element
Understand the concepts of chemical bonds and chemical reactions.
the making and breaking of chemical bonds, leading to changes in the composition of matter are called chemical reations
Describe the three components of nucleotides, and be able to number the carbons of the monomers sugar.
nucleotides are composed of a phosphate group, a 5-C sugar (ribose or deoxyribose), and a nitrogenous base. Start numbering at the carbon on the right of the oxygen.
Describe how hydrogen bonding determines many properties of water.
the dipole in water molecules allows molecules of water to hydrogen bond with each other. hydrogen bonds give water its high boiling point
Explain the two basic mechanisms by which evolutionary change occurs
hereditary variations and the overproduction of offspring and competition can cause differences in the reproductive success of individuals, leading to natural selection
Discuss the properties of water that are critical for the survival of living organisms.
- cohesion of water molecules: helps pull water upward in the microscopic water-conducting cells of plants - moderation of temperature by water: water moderates air temperature by absorbing heat from air that is warmer (since it has a high specific heat capacity) and releasing the stored heat to air that is cooler (since it has a high heat of vaporization) - floating of ice on water: allows life to exist under the frozen surfaces of lakes and polar seas - water is the solvent of life
Know which elements compose most of the mass of all living organisms.
Oxygen, carbon, hydrogen and nitrogen make up approximately 96% of all living matter
Describe the major differences between light and electron microscopes.
light microscopes use light for illumination, whereas electron microscopes use electron beams. electron microscopes also have a higher resolution. cell dies in electron microscope
Describe how a molecules shape is important for its ability to interact with other molecules
shape is usually the basis for the recognition of one biological molecule by another
Describe the four major classes of organic molecules and macromolecules found in living organisms.
- carbohydrates serve as fuel and building material - lipids are a diverse group of hydrophobic molecules - proteins include a diversity of structures, resulting in a wide range of functions - nucleic acids store, transmit, and help express hereditary information
Identify and distinguish between the three types of membrane proteins.
- Integral proteins are embedded in the lipid bilayer: hydrophobic regions extend into the hydrophobic interior and hydrophilic regions are in contact with the aqueous solution on one or both sides of the membrane - peripheral proteins are loosely attached to the membrane surface - glycoproteins have short, branched carbohydrates bonded to them
Describe the variety and chemical characteristics of common functional groups of organic compounds.
- hydroxyl (-OH): polar, H bonds with water to dissolve compounds - carbonyl (-C=O): polar - carboxyl (O=C-OH): polar, acts as acid - amino (-NH2): acts as base - sulfhydryl (-SH): two -SH groups can react, forming a "cross-link" that helps stabilize protein structure - phosphate (-OPO3^-2): contributes negative charge - methyl (-CH3): affects expression of genes when on DNA or on proteins bound to DNA
Compare and contrast the types of atomic interactions that lead to the formation of molecules.
molecules can be formed by covalent or ionic bonds. Covalent bonds involve atoms sharing electrons where as ionic bonds involve the transfer of electrons from one atom to another
Explain the term antiparallel and describe its importance for base pairing.
antiparallel refers to the arrangement of the sugar phosphate backbones in a DNA double helix (they run in opposite 5' to 3' directions). it is important for base pairing because it allows the bases to line up with their complementary partner, forming hydrogen bonds
Understand the nature and importance of hydrogen bonds in living systems.
hydrogen bonding occurs between hydrogen and an electronegative atom. it is important in DNA structure
Describe the chemical nature of steroids and give two examples of their biological function.
steroids are composed of four fused rings with attached chemical groups. They are used as components of cell membranes (cholesterol) and as signalling molecules that travel through the body (hormones)
Describe the levels of protein structure, and understand the bonding forces and factors that are important in determining polypeptide and protein shape.
Protein structure: - primary: sequence of amino acids - secondary: alpha helix and beta pleated sheets - tertiary: 3-D shape (a-helix and B-sheets) - quaternary: 2 or more subunits, multimeric complexes factors promoting protein folding and stability: - H bonding - ionic bonds - hydrophobic effects - Van der Waals forces - disulfide bridges
Explain how life can be viewed at different levels of biological complexity
biosphere > ecosystem > community > population > organism > organ system > organ > tissue > cell > organelle > molecule > atom
Explain the concept of electronegativity and its contribution to the polarity of some covalent bonds.
electronegativity is an atoms ability to attract electrons in a covalent bond. If one atom in a bond is more electronegative, the electrons in the bond will not be shared equally, resulting in a polar covalent bond.
Give examples of the general types of functions that are carried out in cells by different types of proteins.
- gene/protein expression - structural support - storage - transport - cellular communications - movement - defense
Describe hypothesis testing, theories, and describe the scientific method
A hypothesis is a tentative answer to a well-framed question - an explanation on trial. A theory is an explanation that is broader in scope than a hypothesis, generates new hypotheses, and is supported by a large body of evidence. The key ingredient of the scientific method is the hypothesis-based inquiry method, which is an approach to problem-solving that involves: 1. Asking a question and formulating a tentative answer or hypothesis by inductive reasoning (specific to general). 2. Using deductive reasoning (general to specific) to make predictions from the hypothesis and then testing the validity of those predictions.
Explain how researchers study biology at different levels, ranging from molecules to ecosystems
The study of biology balances the reductionist strategy (systems biology - where they attempt to model the dynamic behaviour of whole biological systems based on a study of the interactions among the systems parts) with the goal of understanding how the parts of cells, organisms, and populations are functionally integrated.
List the different classes of lipid molecules that are important in living organisms.
fats, phospholipids, steroids
List the properties of water that make it a valuable solvent, and distinguish between hydrophilic and hydrophobic substances.
Water is an unusually versatile solvent because its polar molecules are attracted to charged and polar substances capable of forming hydrogen bonds. Hydrophilic substances have an affinity for water and hydrophobic substances do not.
Explain what domains are and their importance in proteins.
a domain is a discrete structural and functional region of a protein that performs the same task in any protein it is found. Domains shuffled via mutations may lead to new proteins with new roles
Explain how water has the ability to ionize into hydroxide ions (OH-) and into hydrogen ions (H+), and how the H+ concentration is expressed as a solutions pH.
occasionally, a hydrogen atom participating in hydrogen bond between two water molecules shifts from one molecule to the other. When this happens, the hydrogen atom leaves its electron behind, and what is actually transferred is a hydrogen ion (H+). The water molecule that lost a proton is now a hydroxide ion (OH-). The pH of a solution is the negative log of the hydrogen ion concentration: pH=-log[H+]
Describe the fluid-mosaic model of membrane structure.
the fluid mosaic model envisions the membrane as a mosaic of protein molecules drifting laterally in a fluid bilayer of phospholipids
Describe the structures and general functions of semi-autonomous organelles
the semi-autonomous organelles are the mitochondria and chloroplasts because they have their own DNA, mRNA, tRNA, ribosomes and they replicate by binary fission so they are said to be self governing. they are not completely autonomous but they are in a symbiotic relationship with the cell and have evolved to become part of it.
Describe the principles of biology and common themes of life
- new properties emerge at each level in the biological hierarchy - organisms interact with other organisms and the physical environment - life requires energy transfer and transformation - structure and function are correlated at all levels of biological organization - the cell is an organisms basic unit of structure and function - the continuity of life is based on heritable information in the form of DNA - feedback mechanisms regulate biological systems - evolution is the core theme of biology
Distinguish among different forms of carbohydrate molecules, including monosaccharides, disaccharides, and polysaccharides.
- monosaccharides are simple sugars composed of 5 or 6 carbons, they can be linear or in a ring (forms ring in aqueous solutions) examples: ribose, glucose - disaccharides are composed of two monosaccharides joined by a glycosidic linkage, they are formed by a dehydration/condensation reaction and are broken apart by hydrolysis. examples: sucrose, maltose, lactose - polysaccharides are composed of many monosaccharides linked together to form long polymers. examples: starch & glycogen used for energy storage and cellulose & chitin used for structural support
Explain the three important parameters in microscopy: resolution, contrast, and magnification.
- resolution: the ability to observe two adjacent objects as distinct from one another (clarity) - contrast: the ability to distinguish different structures or the difference in brightness between light and dark areas of an image (can be enhanced using dyes) - magnification: ratio between the size of an image produced by a microscope and its actual size
Describe the properties and roles of the cytoskeleton
the cytoskeleton provides mechanical support for the cell and anchorage for organelles. Cytoskeleton is made up of a network of 3 different types of protein filaments: - microtubules (shape cell, guide organelle movement, and separate chromosomes in dividing cells) - intermediate filaments (support cell shape and fix organelles in place) - actin filaments (thin rods functioning in muscle contraction, amoeboid movement, cytoplasmic streaming, and support of microvilli)
Relate phospholipids structure to its ability to form bilayers in aqueous environments.
phospholipids have a hydrophilic head and a hydrophobic tail so they form a bilayer with their heads pointing out (toward water) and their tails pointing in (away from water)
Describe how certain bases can pair with others to form a DNA double helix
complementary bases form H-bonds in the interior of the helix (A forms 2 H-bonds with T and C forms 3 with G)
Discuss why fats function more efficiently than carbohydrates as energy-storage molecules.
1g of fat stores twice as much energy as 1g of glycogen or starch
Distinguish between the structures of DNA and RNA.
Relate the functions of plant and animal polysaccharides to their structure.
starch and glycogen are used for energy storage because they can be easily hydrolyzed to provide sugar for cells. chitin and cellulose are used for structural support because they have beta glycosidic linkages, so every other glucose monomer is "upside-down". this allows molecules to be straight and free to hydrogen bond with parallel molecules, making the molecule strong and difficult to break down
Quantify atomic mass by using units, such as daltons and moles.
The mass of an electron is so small that we can use the mass of the protons plus the mass of the neutron in an atom to determine its approximate atomic mass. Both protons and neutrons have a mass of 1 dalton (or 1 atomic mass unit)
Understand what polarity means for a strand of DNA or RNA.
Discuss the way electrons orbit the nucleus of an atom within discrete energy levels.
Electrons occupy specific electron shells; the electrons in a shell have a characteristic energy level. electron distribution in shells determines the chemical behaviour of an atom. electrons exist in orbitals, 3-D spaces with specific shapes that are components of electron shells.
Understand the structure of triglycerides and how the structure and melting point are affected by the presence of saturated and unsaturated fatty acids.
triglycerides are composed of a glyceride molecule and three fatty acids. Saturated fatty acid tails lack double bonds and their flexibility allows the fat molecules to pack together tightly, making them solid at room temperature and increasing melting point. Double bonds in unsaturated fatty acid tails prevent the molecules from packing together, making them liquid at room temperature and lowering melting point
Explain how amino acids are joined to form a polypeptide, and distinguish between a polypeptide and protein.
joined by dehydration reaction. proteins are made up of one or more polypeptides
Understand molarity of a solution and its relation to the concentration of solutes in solution.
molarity, the number of moles of solute per litre of solution, is used as a measure of solute concentration
Compare and contrast the general structural/functional features of prokaryotic and eukaryotic cells.
eukaryotic cells have a membrane bound nucleus and organelles
Describe how changes in genomes underlie evolutionary changes
different genomes could be more beneficial and therefore, the organisms with these altered genomes have a higher chance of surviving and passing on their genes, thereby causing evolution
Section 2
(40 cards)