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124 Cards in this Set
- Front
- Back
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What do the unique properties of small molecules arise from?
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The orderly arrangement of its atoms.
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What are the major groups of biologically important molecules?
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Carbohydrates, lipids, proteins, and nucleic acids.
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What are macromolecules?
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Giant molecules formed by the union of smaller molecules.
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What are polymers?
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Long chains formed by linking small organic molecules called monomers.
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What is polymerization?
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The linking together of monomers to form polymers.
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Through what process does polymerization take place?
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Through dehydration reactions.
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What is condensation?
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The chemical process by which monomers are linked together.
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What is it called when a molecule of water is removed?
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Dehydration synthesis.
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What is hydrolysis?
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The chemical process by which polymers can be degraded into monomers.
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What does the uniqueness of organisms depend on?
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The unique arrangement of the same monomers.
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How many monomers are macromolecules constructed from?
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Only 40 to 50 common monomers and some others that occur rarely.
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At what ratio do carbon, hydrogen, and oxygen appear in carbohydrates?
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1:2:1.
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What are monosaccharides?
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Simple sugars.
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What do monosaccharides serve as sources of?
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Energy and carbon atoms.
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How many carbon atoms do monosaccharides usually contain?
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3 to 7 carbon atoms.
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Where are hydroxyl groups in monosaccharides?
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They are bonded to each carbon except one.
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In monosaccharides, what functional group is bonded to the carbon that isn't bonded to a hydroxyl group?
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That carbon is double bonded to an oxygen atom, forming a carbonyl group.
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What varies based on the carbonyl group in monosaccharides?
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It could make the sugar an aldehyde (at the end) or a ketone (in the middle).
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What kind of monosaccharide are glucose and fructose?
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Aldose and ketose, respectively.
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What are dissaccharides?
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Two monosaccharide units.
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How are two monosaccharide rings joined?
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By a glycosidic linkage.
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What is a glycosidic linkage?
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A covalent bond formed between two monosaccharides by a dehydration reaction.
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How do dissaccharides become split?
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By the addition of water, hydrolysis.
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What monosaccharides join to form maltose?
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Two glucose monomers.
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What monosaccharides join to form sucrose?
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One glucose monomer and one fructose monomer.
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What monosaccharides join to form lactose, the sugar in milk?
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One glucose monomer and on galactose monomer.
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What are polysaccharides?
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Repeating chains of monosaccharides.
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What are the functions of polysaccharides?
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They function either as energy storage material or as building blocks of cellular structures.
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What is starch made of and what is its function?
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Made entirely of glucose. It is the main storage carbohydrate of plants.
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What is the simplest form of starch and what is its shape?
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Amylose. It is unbranched and helical.
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What is the most complex form of starch and how is it formed?
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Amylopectin. It is a branched form with 1-6 linkages at the branch point.
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What is the storage carbohydrate of animals and how is it formed?
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Glycogen is made of glucose with 1-4 linkages.
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Where is glycogen stored?
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Mostly in the liver and muscles.
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What is cellulose made of and how is it formed?
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It is made of glucose monomers and is a structural carbohydrate with 1-4 linkages.
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How are glucose molecules arranged in cellulose?
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Every other glucose monomer is upside down.
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What shape are cellulose molecules?
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Straight and never branched.
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What is the function of cellulose in plant cell walls?
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They form minute cables called microfibrils.
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What is chitin's function?
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It is used by arthropods in building the exoskeleton.
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What is the chitin monomer?
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It is a glucose-like molecule called N-acetylglucosamine in which an OH group is replaced by a chain of R-NHCOCH3 groups.
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What must chitin contact to become hard?
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Calcium carbonate.
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What is galactosamine?
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It is a structural carbohydrate present in cartilage; it is an amino derivative of galactose, an enantiomer of glucose.
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Where are glycoproteins and glycolipids found?
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Found on the outer surface of cells.
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What are glycoproteins and glycolipids?
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They are proteins with polysaccharide or fatty acid branches attached.
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What are lipids composed of?
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Mostly of carbon and hydrogen, with a few oxygen atoms found mainly in functional groups.
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How do lipids interact with water?
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They are hydrophobic molecules (water repellent).
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What kind of solvent are lipids soluble?
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Nonpolar solvents.
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What are lipids used for?
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Energy storage, hormones, and the structure of cell membranes.
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What are fats?
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Molecules made from smaller molecules linked by dehydration reactions.
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What are neutral fats made of?
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Glycerol and three fatty acids.
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What is glycerol?
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A 3-carbon alcohol.
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What are fatty acids?
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Long, unbranched hydrocarbon chains with carboxyl groups at one end.
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What is the reason for the hydrophobic properties of hydrocarbons?
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The nonpolar C-H.
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When do ester linkages occur?
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When a fatty acid combines with a glycerol molecule and a molecule of water is removed.
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What is a synonym for fat?
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Triglyceride.
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What are saturated fats?
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Fats that have a max number of hydrogen atoms in the chain.
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What are unsaturated fats?
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Fats the have double bonds between some of the carbon atoms and have less than the max number of hydrogen atoms.
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Why do unsaturated fats become liquid at room temperature?
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They have bends in the chains that prevent the aligning with adjacent chains.
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What are phospholipids a major compenent of?
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Cell membranes.
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How do phospholipids differ from fats?
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They have 2 fatty acids instead of 3, and a phosphate group with a small additional molecule attached to the third carbon of glycerol instead of a hydroxyl group.
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How do phospholipids interact with water?
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The hydrocarbon chains are hydrophobic but the phosphate group is hydrophilic. (Amphipathic molecule)
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What is a micelle?
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A droplet formed by phospholip molecules arranged with the hydrophilic heads facing out toward the water and their hydrophobic tails facing inward away from water.
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What are bilayers?
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Double membranes where the heads face toward the aqueous solution and the tails point to the interior of the membrane.
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What is cholesterol?
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A steroid component of cell membranes of animals.
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What are waxes?
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Complex lipids made of many fatty acids linked to a long-chain alcohol.
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How are the carbon skeletons of steroids arranged?
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Bent into four fused rings with a carbon chain attached to one of the rings.
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How are carbons distributed in steroids?
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Three rings have six carbon atoms and one has five.
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What properties distinguish one steroid from another?
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The length and structure of the chain.
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What determines the function of steroids?
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The functional groups attached to their carbon rings.
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What is a precursor from which steroids are made?
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Cholesterol.
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What are carotenoids?
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Plant pigments involved in photosynthesis. Insoluble in water.
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What are a few functions of proteins?
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Structural support, transport of other molecules, body defense, signaling between cells, chemical catalysts called enzymes, storage, and others.
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What are proteins composed of?
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Polymers of amino acides joined by peptide bonds.
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What are polymers of amino acids joined by peptide bonds?
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Polypeptides.
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What shape do proteins take?
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They are polypeptides folded and coiled into a specific conformation.
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How many amino acids are involved in proteins?
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20 amino acids.
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What 5 elements can be found in proteins?
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Carbon, hydrogen, oxygen, nitrogen, and usually sulfur.
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How is an amino acid arranged?
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They contain an amino group at one end and a carboxyl group at the other, both attached to an alpha carbon.
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What determines the specific physical and chemical properties of each AA?
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A side chain (R group).
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Which amino acids used to synthesize proteins can exist as L- or D- enantiomorphs?
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All 19 except glycine.
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Which amino acids are used for protein synthesis?
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Only L-amino acids.
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For animals, where must essential amino acids be obtained from?
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They must be obtained from the diet.
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What side chain makes amino acids hydrophobic?
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Non-polar side chains made of hydrocarbons.
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What side chain makes amino acids hydrophilic?
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Polar side chain containing O, S, or N.
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What side chain makes amino acids acidic?
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A negative side chain.
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What side chain makes amino acids basic?
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A positive side chain.
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How do amino acids join together?
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The amino end of one AA joins the carboxyl end of the adjacent AA.
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When amino acids join together, what is the resulting covalent bond called?
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A peptide bond.
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How many peptide bonds must exist to form a polypeptide?
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Thousands.
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Why are polypeptides and proteins not synonymous?
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Proteins consist of one or more polypeptide chains twisted into a unique shape.
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What does the function of a protein depend on?
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Its ability to bind to another molecule.
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How many levels of organization do proteins have?
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4.
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What is the primary structure of proteins?
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A unique sequence of AA for each polypeptide.
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What does the secondary structure of proteins result from?
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Hydrogen bonds between H and O atoms of the backbone of the chain resulting in coiling or folding.
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What is the tertiary structure of proteins?
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The overall shape of the polypeptide due to the interaction among the side chains.
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In proteins where do hydrophobic interactions occur?
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The interior of the twisted polypeptide.
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What do disulfide bridges form between?
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The two sulfhydril groups of the AA cysteine.
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What forces contribute to the tertiary structure of the polypeptide chain in proteins?
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Van der Waals forces.
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What is the quaternary structure of proteins?
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The relationship among several polypeptide chains of a protein.
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What determines the function of proteins?
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Their shapes.
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What kind of conditions does protein conformation depend on?
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The physical and chemical conditions of the environment like salt concentration, temperature, and pH.
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What would cause proteins to become denatured?
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Changes in any of the physical and chemical conditions of the environment.
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What do chaperonins do?
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They help in the proper folding of proteins, but they don't specify the conformation.
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What programs all of the cells activities?
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The information encoded in the structure of DNA.
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What do genes do?
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They determine the polymer sequence of amino acids in a protein.
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What do DNA and RNA do?
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Transmit hereditary information and determine what the cells manufacture.
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What is the flow of genetic information within the cell?
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DNA--> mRNA --> protein.
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Where does protein synthesis take place?
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In organelles called ribosomes found in the cytoplasm of the cell.
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What does messenger RNA do?
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It is synthesized in the nucleus following the DNA blueprint and then moves to the ribosomes with the message about the protein to be synthesized.
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What are nucleic acids polymers of?
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Nucleotides.
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What is another name for nucleic acids?
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Polynucleotides.
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What 3 parts are nucleotides made of?
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A nitrogenous base, a pentose sugar, and a phosphate group.
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What are the groups of nitrogenous bases called?
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Pyrimidines and purines.
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What is the structure of pyrimidines?
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A 6 member ring of carbon and nitrogen atoms.
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What are the 3 pyrimidines?
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Cytosine, thymine, and uracil.
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Where does the term nitrogenous base come from?
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Nitrogen atoms tend to take the H+ from water.
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Where is thymine and uracil found?
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DNA and RNA respectively.
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Where is cytosine found?
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Both DNA and RNA.
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What is the structure of purines?
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A 6 member ring fused to a 5 member ring composed of nitrogen and carbon.
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What are the two purines and where are they found?
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Adenine and guanine. Found in DNA and RNA.
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What are the pentose sugars?
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Ribose in RNA and deoxyribose in DNA.
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What must join to form a nucleoside?
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The combination of a sugar with a nitrogenous base.
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What must join to form a nucleotide?
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The addition of a phosphate group to a nucleoside, hence the name nucleoside monophosphate.
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What are phosphodiester bonds?
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Covalent bonds between the phosphate on one nucleotide and the sugar of the next.
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Why are two strands of a double helix complementary?
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Only certain bases are compatible to establish the required hydrogen bonds. E.g. Adenine pairs with thymine and guanine pairs with cytosine.
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