Section 1
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lipids
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Date created
Mar 1, 2020
Cards (84)
Section 1
(50 cards)
lipids
- diverse group of organic compounds that are insoluble in water but dissolve in nonpolar solvents - do not have true polymers - too small to be considered macromolecules - hydrophobic because they have mostly hydrocarbon regions - varied in form and function - fats, phospholipids, steroids, waxes
enzymatic proteins
- accelerate chemical reactions - digestive enzymes catalyze hydrolysis of food molecules
transport proteins
- transport of substances - hemoglobin transports oxygen from lungs to other parts of body through the bloodstream
aldehyde sugars
- carbonyl group at the end of a carbon skeleton - ex. glyceraldehyde, ribose, glucose, galactose
diversity of polymers
- cells have thousands of different macromolecules - closely related organisms have small differences in polymers (ex. DNA and proteins) - organisms have extensive molecular differences because the diversity of macromolecules is vast and the variety is limitless - there are 40-50 common monomers in which various combinations can be made, thus creating diversity - polymers are made up different monomers and arranged in various ways - small molecules are common to all organisms but ordered into unique macromolecules - despite diversity, members of each of the 4 classes of macromolecules are similar in structure and function
saturated fatty acids
- a fatty acid with no carbon double bonds - maximum amount of hydrogen bonded to the carbon skeleton, so it is saturated - solid at room temperature - straight chain - most animal fats are saturated and flexibility allows tight packing - ex. bacon grease, butter
enzyme
a specialized protein macromolecule that speeds up chemical reactions
triacylglycerol
a fat composed of three fatty acids bonded to one glycerol by ester linkages
fats and diet
- diet rich in saturated fats can contribute to cardiovascular diseases such as atherosclerosis - plaque deposits develop within walls of blood vessels and bulge inwards - impedes blood flow and reduces vessels' relsilience
trioses
- sugars that have three carbons - glyceraldehyde, dihydroxyacetone
storage polysaccharides
- plants and animals store sugars for later use in the form of storage polysaccharides - starch is stored in plants and can be withdrawn by hydrolysis - glycogen is stored in animals and used for short term storage
unsaturated fatty acids
- a fatty acid with one or more carbon double bonds - for every double bond, there is fewer hydrogen bonds - liquid at room temperature - double bonds cause kinks, or bends, in the chain - most plant fats - ex. olive oil, corn
dehydration reaction
- a reaction where polymers are synthesized - two molecules are covalently bonded to each other - a water molecule is lost - each monomer contributes part of the water molecule during the reaction: one provides hydroxyl (OH), the other provides hydrogen (H) - repeats to create longer chains, or polymers - requires energy and biological catalysts - a.k.a dehydration synthesis or condensation
polypeptide
a polymer of many amino acids linked by peptide bonds that makes up proteins
amino acid
- an organic molecule with both an amino group and a carboxyl group - amino group: NH₂ (left) - alpha (α) carbon in center that connects to four different partners - hydrogen atom (bottom) - carboxyl group: COOH (right) - R group, or side chain (top) - physical and chemical properties of the side chain determine the characteristics of the amino acid - amino groups and carboxyl grouups are usually ionized at the pH level in the cell
trans fat
- unsaturated fats that have been altered through hydrogenation so that instead of cis bonds, the hydrogen forms trans bonds - chain is straight because of trans bonds - may contribute more than saturated fats to disease
peptide bond
a covalent bond between amino acids that makes up polypeptides through dehydration reactions
monomer
- the repeating units that serve as the building blocks of a polymer that are smaller molecules - have other functions of their own
disaccharide
- a double sugar that consists of two monosaccharides joined by a glycosidic linkage - maltose: glucose + glucose; malt sugar in brewing beer - sucrose: glucose + fructose; table sugar and used to transport carbohydrates from leaves to roots in plants (most prevalent disaccharide) - lactose: glucose + galactose; milk sugar
polymer
- a long molecule consisting of many similar or identical building blocks/subunits linked by covalent bonds - carbohydrates, proteins, and nucleic acid macromolecules all form chains of polymers - made out of monomers
storage proteins
- storage of amino acids - casein, protein of milk, is a source of amino acids for baby mammals
fats
- large molecules assembled from glycerol and fatty acids by a dehydration reaction - major function is energy storage - gram of fat stores more than twice as much energy as a gram of a polysaccharidie - less bulky and allow animals to carry energy in a compact reservoir via adipose cells that shrink and swell as fat is added or removed - adipose tissue cushions organs and insulated the body - hydrophobic because they have hydrocarbon chains of fatty acids - separate from water because the water hydrogen-bonds with itself and excludes fat - composed of three fatty acid molecules that are joined to glycerol by an ester linkage: results in a triacylglycerol - can be three different fatty acids or the same - saturated, unsaturated, or trans
fatty acid
- a smaller molecule that has a long carbon skeleton (16-18 carbons) - carbon at one end is part of a carboxyl group - rest of the skeleton is a hydrocarbon chain - nonpolar C-H bonds make it hydrophobic
structural proteins
- support - keratin supports hair
defensive proteins
- protection against disease - antibodies destroy viruses
hydrolysis
- a reaction where polymers are broken down - bond between monomers is broken - a water molecule is added - hydrogen (H) attaches to one monomer and hydroxyl (OH) attaches to the other monomer - ex. digestion: organic material in good is too large to enter cells, so enzymes attack polymers and speed up hydrolysis; released monomers can be absorbed into the bloodstream and dehydration can be used to form new specialized polymers for the cell
macromolecules
- a giant molecule formed by the joining of smaller molecules, usually by a dehydration reaction - carbohydrate, protein, or nucleic acid (lipids do not include true polymers and generally too small to be classified as a macromolecule) - relatively large - may consist of thousands of covalently bonded atoms and have a mass more than 100,000 daltons - very complex and have a detailed structure - architecture plays an essential role in function - exhibit unique emergent properties that arise from the orderly arrangement of their atoms
polysaccharides
- macromolecules and polymers with a few hundred to a few thousand monosaccharides joined by glycosidic linkages - storage material and hydrolyzed as needed to provide sugar for cells (starch in plants and glycogen in animals) - building material for structures that protect the cell or the whole organism (cellulose in plants and chitin in arthropods) - architecture and function determined by the sugar monomers and position of the glycosidic linkages
proteins
- a biologically functional molecule that is made up of one or more polypeptides that is folded into a specific three-dimensional structure - humans have tens of thousands of proteins which have different structures and functions - constructed from the same set of 20 amino acids - 50% of dry mass of most cells - most important macromolecule, instrumental in everything organisms do
pentoses
- sugars that have five carbons - ribose, ribulose
contractile and motor proteins
- movement - motor proteins cause undulations of cilia and flagella - actin and myosin cause muscle contraction
protein functions
- enzymes - defense - storage - transport - hormonal - receptor - contractile and motor - structural
glycogen
- polymer of glucose - extensively branched - stored in liver and muscle cells in vertebrates - hydrolysis in cells release glucose when demand increases - cannot sustain long-term - depleted in about a day until replenished by consumption of food - low-carb diets result in weakness
hormonal proteins
- coordinate organism's activities - insulin causes tissues to take up glucose and regulates the blood sugar concentration
ketone sugars
- carbonyl group within carbon skeleton - ex. dihydroxyacetone, ribulose, fructose
hexoses
- sugars that have six carbons - glucose, fructose, galactose
structural polysaccharides
- polysaccharides which organisms build strong materials from - cellulose in plants is part of plant cell enclosures - chitin in arthropods is used for their exoskeletons
carbohydrates
- macromolecules that serve as fuel and building material - energy used right away, easier to use and with less energy (short-term) - include sugars and their polymers - polymers made by dehydration - classified by the number of simple sugars - can be monosaccharides, disaccharides, or polysaccharides
characteristics of sugar
- carbonyl group (CO) which oxygen is double bonded to carbon - multiple hydroxyl groups (OH) attached to each carbon except one - either an aldose (aldehyde sugar) or a ketose (ketone sugar) - size of carbon skeleton can range from 3 to 7 carbons long - spatial arrangement around asymmetric carbons can vary (enantiomers: glucose and galactose), causing different biochemical properties - form rings in aqueos solutions
phospholipids
- a type of lipid similar to a fat molecule but has only two fatty acids attached to glycerol, and the third hydroxyl group of glycerol is attached to a negatively charged phosphate - two ends show different behavior to water: hydrocarbon tails are hydrophobic; phosphate group forms a hydrophilic head that has an affinity for water - assembles into bilayers and shields the hydrophobic portions from water - arranged in a similar bilayer in cells as the hydrophilic heads is on the outside that makes contact with substances and the hydrophobic head is on the inside - bilayer separates the cell and the environment - ex. choline
catalysts
- chemical agents that selectively speed up chemical reactions without being consumed by the reaction - regulate metabolism - most enzymes are proteins
receptor proteins
- response of cell to chemical stimuli - receptors in nerve cell membrane detect signaling molecules from other nerves
monosaccharides
- simple sugars - generally have molecular formulas that are some multiple of the unit CH₂O - the most common monosaccharide is glucose (C₆H₁₂O₆) - major nutrients for cells, particularly glucose - can be produced by photosynthetic organisms - store energy in chemical bonds which can be harvested by cellular respiration, a process where cells extract energy by breaking molecules down in a series of reactions - carbon skeletons are raw material for the synthesis of other organic molecules (ex. amino acids, fatty acids) - can be incporated as monomers in disaccharides and polysaccharides
glycosidic linkage
- a covalent bond formed between two monosaccharides by a dehydration reaction - the hydroxyl of one monosaccharide bonds with the hydrogen of the hydroxyl of another monosaccharide, which forms H₂O - the remaining oxygen molecule links the two monomers - alpha (α) or beta (β) ring forms - different links give distinct three-dimensional shapes
ester linkage
a bond formed by a dehydration reaction between a hydroxyl group and a carboxyl group that produces a triacylglycerol
starch
- a polymer of glucose monomers - alpha (α) ring forms: the hydroxyl group attached to the number one carbon is below the plane of the ring (all on the same side) - helical - a storage polysaccharide - in the form of granules within cellular structures called plastids that have chloroplasts - synthesis enables accumulation of glucose - represents stored energy - sugar can be withdrawn from starch by hydrolysis, which breaks glucose monomer bonds - humans and other animals have enzymes that hydrolyze plant starch for nutrients - glucose, monomers in starch, usually joined by 1-4 linkages - amylose, the simplest starch, is unbranched - amlyopectin, a complex starch, is branched with 1-6 linkages
steroids
- lipids that have a carbon skeleton of four fused rings which have various chemical groups attached to it - chemical messengers and send chemical signals to cells - ex. cholesterol: steroid molecule that is in cell membranes and precursor of sex hormones and other molecules - saturated fats and trans fats affect cholesterol levels which can contribute to cardiovascular disease
chitin
- a structural polysaccharide - carbohydrate used by arthropods to build exoskeletons - embedded in a layer of proteins so the exoskeleton is leathery and flexible initially, and then hardened as proteins are linked and calcium carbonate encrusts it - found in fungi as a replacement for cellulose - similar to cellulose but has a nitrogen-containing appendage in glucose
4 major classes of large biological molecules
carbohydrates, lipids, proteins, nucleic acids
cellulose
- a structural polysaccharide in plants which is a polymer of glucose - major component of tough cell walls in plants - beta (β) ring forms: the hydroxyl group attached to the number 1 carbon is upside down compared to its adjacent glucose monomer (alternating sides) - straight and never branched - hydroxyl groups can bond with parallel cellulose which creates groups called microfibrils, strong building material and part of paper and cotton - enzymes cannot break down both alpha and beta links; few organisms can digest cellulose and eliminated as feces - part of a healthy diet; abrades digestive tract and causes mucus secretion - most abundant organic compound on Earth: over 100 billion tons produced each year
Section 2
(34 cards)