chapter 5

Which of the following uses the amino acid sequences of polypeptides to predict a proteinʹs three -dimensional structure? A) X-ray crystallography B) bioinformatics C) analysis of amino acid sequence of small fragments D) NMR spectroscopy E) high-speed centrifugation

bioinformatics

On food packages, to what does the term ʺinsoluble fiberʺ refer? A) cellulose B) polypeptides C) starch D) amylopectin E) chitin

cellulose

What is the term used for a protein molecule that assists in the proper folding of other proteins? A) tertiary protein B) chaperonin C) enzyme protein D) renaturing protein E) denaturing protein

chaperonin

Which of the following polymers contain nitrogen? A) starch B) glycogen C) cellulose D) chitin E) amylopectin

chitin

All of the following contain amino acids except A) hemoglobin. B) cholesterol. C) antibodies. D) enzymes. E) insulin.

cholesterol.

What is the structural feature that allows DNA to replicate? A) sugar-phosphate backbone B) complementary pairing of the nitrogenous bases C) disulfide bonding (bridging) of the two helixes D) twisting of the molecule to form an α helix E) three-component structure of the nucleotides

complementary pairing of the nitrogenous bases

The difference between the sugar in DNA and the sugar in RNA is that the sugar in DNA A) is a six-carbon sugar and the sugar in RNA is a five-carbon sugar. B) can form a double-stranded molecule. C) has a six-membered ring of carbon and nitrogen atoms. D) can attach to a phosphate. E) contains one less oxygen atom.

contains one less oxygen atom.

Which of the following are nitrogenous bases of the pyrimidine type? A) guanine and adenine B) cytosine and uracil C) thymine and guanine D) ribose and deoxyribose E) adenine and thymine

cytosine and uracil

What is the chemical mechanism by which cells make polymers from monomers? A) phosphodiester linkages B) hydrolysis C) dehydration reactions D) ionic bonding of monomers E) the formation of disulfide bridges between monomers

dehydration reactions

The function of each protein is a consequence of its specific shape. What is the term used for a change in a proteinʹs three-dimensional shape or conformation due to disruption of hydrogen bonds, disulfide bridges, or ionic bonds? A) hydrolysis B) stabilization C) destabilization D) renaturation E) denaturation

denaturation

There are 20 different amino acids. What makes one amino acid different from another? A) different carboxyl groups attached to an alpha (α) carbon B) different amino groups attached to an alpha (α) carbon C) different side chains (R groups) attached to an alpha (α) carbon D) different alpha (α) carbons E) different asymmetric carbons

different side chains (R groups) attached to an alpha (α) carbon

A strong covalent bond between amino acids that functions in maintaining a polypeptideʹs specific three-dimensional shape is a (an) A) ionic bond. B) hydrophobic interaction. C) van der Waals interaction. D) disulfide bond. E) hydrogen bond.

disulfide bond.

A molecule with the formula C18H36O2 is probably a

fatty acid.

Of the following functions, the major purpose of RNA is to A) transmit genetic information to offspring. B) function in the synthesis of protein. C) make a copy of itself, thus ensuring genetic continuity. D) act as a pattern or blueprint to form DNA. E) form the genes of higher organism

function in the synthesis of protein

Which of the following is not a polymer? A) glucose B) starch C) cellulose D) chitin E) DNA

glucose

All of the following are polysaccharides except A) glycogen B) starch C) chitin D) cellulose E) amylopectin

glycogen

The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are the α form. Which of the following could amylase break down? A) glycogen B) cellulose C) chitin D) A and B only E) A, B, and C

glycogen

Which of the following are nitrogenous bases of the purine type? A) cytosine and guanine B) guanine and adenine C) adenine and thymine D) thymine and uracil E) uracil and cytosine

guanine and adenine

In the double helix structure of nucleic acids, cytosine hydrogen bonds to A) deoxyribose. B) ribose. C) adenine. D) thymine. E) guanine.

guanine.

The bonding of two amino acid molecules to form a larger molecule requires which of the following? A) removal of a water molecule B) addition of a water molecule C) formation of an ionic bond D) formation of a hydrogen bond E) both A and C

removal of a water molecule

The α helix and the β pleated sheet are both common polypeptide forms found in which level of protein structure? A) primary B) secondary C) tertiary D) quaternary E) all of the above

secondary

At which level of protein structure are interactions between the side chains (R groups) most important? A) primary B) secondary C) tertiary D) quaternary E) all of the above

tertiary

Which of the following is an example of hydrolysis? A) the reaction of two monosaccharides, forming a disaccharide with the release of water B) the synthesis of two amino acids, forming a peptide with the release of water C) the reaction of a fat, forming glycerol and fatty acids with the release of water D) the reaction of a fat, forming glycerol and fatty acids with the utilization of water E) the synthesis of a nucleotide from a phosphate, a pentose sugar, and a nitrogenous base with the production of a molecule of water

the reaction of a fat, forming glycerol and fatty acids with the utilization of water

The bonding of two amino acid molecules to form a larger molecule requires A) the release of a water molecule. B) the release of a carbon dioxide molecule. C) the addition of a nitrogen atom. D) the addition of a water molecule. E) both B and C

the release of a water molecule.

The tertiary structure of a protein is the A) bonding together of several polypeptide chains by weak bonds. B) order in which amino acids are joined in a polypeptide chain. C) unique three-dimensional shape of the fully folded polypeptide. D) organization of a polypeptide chain into an α helix or β pleated sheet. E) overall protein structure resulting from the aggregation of two or more polypeptide subunits

unique three-dimensional shape of the fully folded polypeptide.

How many molecules of water are needed to completely hydrolyze a polymer that is 11 monomers long? A) 12 B) 11 C) 10 D) 9 E) 8

10

A double-stranded DNA molecule contains a total of 120 purines and 120 pyrimidines. This DNA molecule could be composed of A) 120 adenine and 120 uracil molecules. B) 120 thymine and 120 adenine molecules. C) 120 cytosine and 120 thymine molecules. D) 240 adenine and 240 cytosine molecules. E) 240 guanine and 240 thymine molecules.

120 thymine and 120 adenine molecules.

How many different kinds of polypeptides, each composed of 12 amino acids, could be synthesized using the 20 common amino acids?

20^12

If one strand of a DNA molecule has the sequence of bases 5ʹATTGCA3ʹ, the other complementary strand would have the sequence A) 5ʹTAACGT3ʹ. B) 3ʹTAACGT5ʹ. C) 5ʹUAACGU3ʹ. D) 3ʹUAACGU5ʹ. E) 5ʹUGCAAU3ʹ.

3ʹTAACGT5ʹ.

If a DNA sample were composed of 10% thymine, what would be the percentage of guanine? A) 10 B) 20 C) 40 D) 80 E) impossible to tell from the information given

40

Upon chemical analysis, a particular polypeptide was found to contain 100 amino acids. How many peptide bonds are present in this protein? A) 101 B) 100 C) 99 D) 98 E) 97

99

The R group or side chain of the amino acid serine is —CH2OH. The R group or side chain of the amino acid alanine is —CH3. Where would you expect to find these amino acids in a globular protein in aqueous solution? A) Serine would be in the interior, and alanine would be on the exterior of the globular protein. B) Alanine would be in the interior, and serine would be on the exterior of the globular protein. C) Both serine and alanine would be in the interior of the globular protein. D) Both serine and alanine would be on the exterior of the globular protein. E) Both serine and alanine would be in the interior and on the exterior of the globular protein.

Alanine would be in the interior, and serine would be on the exterior of the globular protein.

Misfolding of polypeptides is a serious problem in cells. Which of the following diseases are associated with an accumulation of misfolded proteins? A) Alzheimerʹs B) Parkinsonʹs C) diabetes D) A and B only E) A, B, and C

Alzheimerʹs & Parkinsonʹs

The molecular formula for glucose is C6H12O6. What would be the molecular formula for a molecule made by linking three glucose molecules together by dehydration reactions? A) C18H36O18 B) C18H30O15 C) C6H10O5 D) C18H10O15 E) C3H6O3

C18H30O15

Which of the following statements best summarizes the structural differences between DNA and RNA? A) RNA is a protein, whereas DNA is a nucleic acid. B) DNA is a protein, whereas RNA is a nucleic acid. C) DNA nucleotides contain a different sugar than RNA nucleotides. D) RNA is a double helix, but DNA is single-stranded. E) A and D are correct.

DNA nucleotides contain a different sugar than RNA nucleotides

Which of the following best describes the flow of information in eukaryotic cells? A) DNA → RNA → proteins B) RNA → proteins → DNA C) proteins → DNA → RNA D) RNA → DNA → proteins E) DNA → proteins → RNA

DNA → RNA → proteins

Which of the following best summarizes the relationship between dehydration reactions and hydrolysis? A) Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers. B) Macromolecular synthesis occurs through the removal of water and digestion occurs through the addition of water. C) Dehydration reactions can occur only after hydrolysis. D) Hydrolysis creates monomers, and dehydration reactions break down polymers. E) A and B are correct

Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers. & Macromolecular synthesis occurs through the removal of water and digestion occurs through the addition of water.

A molecule with the chemical formula C6H12O6 is probably a A) carbohydrate. B) lipid. C) monosaccharide D) A and B only. E) A, B, and C.

E

Altering which of the following levels of structural organization could change the function of a protein? A) primary B) secondary C) tertiary D) quaternary E) all of the above

E

Dehydration reactions are used in forming which of the following compounds? A) triacylglycerides B) polysaccharides C) proteins D) A and C only E) A, B, and C

E

The hydrogenation of vegetable oil results in which of the following? A) saturated fats and unsaturated fats with trans double bonds B) an increased contribution to artherosclerosis C) the oil (fat) being a solid at room temperature D) A and C only E) A, B, and C

E

What would be an unexpected consequence of changing one amino acid in a protein consisting of 325 amino acids? A) The primary structure of the protein would be changed. B) The tertiary structure of the protein might be changed. C) The biological activity or function of the protein might be altered. D) Only A and C are correct. E) A, B, and C are correct.

E

Which of the following is true of cellulose? A) It is a polymer composed of sucrose monomers. B) It is a storage polysaccharide for energy in plant cells. C) It is a storage polysaccharide for energy in animal cells. D) It is a major structural component of plant cell walls. E) It is a major structural component of animal cell plasma membranes

It is a major structural component of plant cell walls.

For this pair of items, choose the option that best describes their relationship. (A) The probability of finding chitin in fungal cell walls (B) The probability of finding chitin in arthropod exoskeletons A) Item (A) is greater than item (B). B) Item (A) is less than item (B). C) Item (A) is exactly or very approximately equal to item (B). D) Item (A) may stand in more than one of the above relations to item (B).

Item (A) is exactly or very approximately equal to item (B).

For this pair of items, choose the option that best describes their relationship. (A) The number of purines in the DNA strand 5ʹ-AAGAGGAGAAA-3ʹ (B) The number of pyrimidines in the DNA strand 5ʹ-AAGAGGAGAAA-3ʹ A) Item (A) is greater than item (B). B) Item (A) is less than item (B). C) Item (A) is exactly or very approximately equal to item (B). D) Item (A) may stand in more than one of the above relations to item (B).

Item (A) is greater than item (B).

For this pair of items, choose the option that best describes their relationship. (A) The probability that amino acids with nonpolar side chains are hydrophobic. (B) The probability that amino acids with side chains containing a carboxyl group are hydrophobic. A) Item (A) is greater than item (B). B) Item (A) is less than item (B). C) Item (A) is exactly or very approximately equal to item (B). D) Item (A) may stand in more than one of the above relations to item (B).

Item (A) is greater than item (B).

For this pair of items, choose the option that best describes their relationship. (A) The number of alpha glucose 1-4 linkages in cellulose (B) The number of alpha glucose 1-4 linkages in starch A) Item (A) is greater than item (B). B) Item (A) is less than item (B). C) Item (A) is exactly or very approximately equal to item (B). D) Item (A) may stand in more than one of the above relations to item (B).

Item (A) is less than item (B).

For this pair of items, choose the option that best describes their relationship. (A) The number of cis double bonds in saturated fatty acids (B) The number of cis double bonds in unsaturated fatty acids A) Item (A) is greater than item (B). B) Item (A) is less than item (B). C) Item (A) is exactly or very approximately equal to item (B). D) Item (A) may stand in more than one of the above relations to item (B).

Item (A) is less than item (B).

Which of the following statements about the 5ʹ end of a polynucleotide strand of DNA is correct? A) The 5ʹ end has a hydroxyl group attached to the number 5 carbon of ribose. B) The 5ʹ end has a phosphate group attached to the number 5 carbon of ribose. C) The 5ʹ end has thymine attached to the number 5 carbon of ribose. D) The 5ʹ end has a carboxyl group attached to the number 5 carbon of ribose. E) The 5ʹ end is the fifth position on one of the nitrogenous bases.

The 5ʹ end has a phosphate group attached to the number 5 carbon of ribose

DNAase is an enzyme that catalyzes the hydrolysis of the covalent bonds that join nucleotides together. What would first happen to DNA molecules treated with DNAase? A) The two strands of the double helix would separate. B) The phosphodiester bonds between deoxyribose sugars would be broken. C) The purines would be separated from the deoxyribose sugars. D) The pyrimidines would be separated from the deoxyribose sugars. E) All bases would be separated from the deoxyribose sugars

The phosphodiester bonds between deoxyribose sugars would be broken

Which of the following is true of both starch and cellulose? A) They are both polymers of glucose. B) They are geometric isomers of each other. C) They can both be digested by humans. D) They are both used for energy storage in plants. E) They are both structural components of the plant cell wall.

They are both polymers of glucose.

Which of the following statements is false for the class of biological molecules known as lipids? A) They are soluble in water. B) They are an important constituent of cell membranes. C) They contain more energy than proteins and carbohydrates. D) They are not true polymers. E) They contain waxes and steroids.

They are soluble in water.

Why are human sex hormones considered to be lipids? A) They are essential components of cell membranes. B) They are steroids, which are not soluble in water. C) They are made of fatty acids. D) They are hydrophilic compounds. E) They contribute to atherosclerosis.

They are steroids, which are not soluble in water

Which of the following is true regarding saturated fatty acids? A) They are the predominant fatty acid in corn oil. B) They have double bonds between carbon atoms of the fatty acids. C) They are the principal molecules in lard and butter. D) They are usually liquid at room temperature. E) They are usually produced by plants.

They are the principal molecules in lard and butter.

All of the following statements concerning saturated fats are true except A) They are more common in animals than in plants. B) They have multiple double bonds in the carbon chains of their fatty acids. C) They generally solidify at room temperature. D) They contain more hydrogen than saturated fats having the same number of carbon atoms. E) They are one of several factors that contribute to atherosclerosis.

They have multiple double bonds in the carbon chains of their fatty acids.

Roger Kornberg used this method for elucidating the structure of RNA polymerase. A) X-ray crystallography B) bioinformatics C) analysis of amino acid sequence of small fragments D) NMR spectroscopy E) high-speed centrifugation

X-ray crystallography

What is a triacylglycerol? A) a protein with tertiary structure B) a lipid made with three fatty acids and glycerol C) a lipid that makes up much of the plasma membrane D) a molecule formed from three alcohols by dehydration reactions E) a carbohydrate with three sugars joined together by glycosidic linkages

a lipid made with three fatty acids and glycerol

Which of the following descriptions best fits the class of molecules known as nucleotides? A) a nitrogenous base and a phosphate group B) a nitrogenous base and a pentose sugar C) a nitrogenous base, a phosphate group, and a pentose sugar D) a phosphate group and an adenine or uracil E) a pentose sugar and a purine or pyrimidine

a nitrogenous base, a phosphate group, and a pentose sugar

Large organic molecules are usually assembled by polymerization of a few kinds of simple subunits. Which of the following is an exception to this statement? A) a steroid B) cellulose C) DNA D) an enzyme E) a contractile protein

a steroid

What method did Frederick Sanger use to elucidate the structure of insulin? A) X-ray crystallography B) bioinformatics C) analysis of amino acid sequence of small fragments D) NMR spectroscopy E) high-speed centrifugation

analysis of amino acid sequence of small fragments

Polysaccharides, lipids, and proteins are similar in that they A) are synthesized from monomers by the process of hydrolysis. B) are synthesized from monomers by dehydration reactions. C) are synthesized as a result of peptide bond formation between monomers. D) are decomposed into their subunits by dehydration reactions. E) all contain nitrogen in their monomer building blocks.

are synthesized from monomers by dehydration reactions.

Lactose, a sugar in milk, is composed of one glucose molecule joined by a glycosidic linkage to one galactose molecule. How is lactose classified? A) as a pentose B) as a hexose C) as a monosaccharide D) as a disaccharide E) as a polysaccharide

as a disaccharide

Humans can digest starch but not cellulose because A) the monomer of starch is glucose, while the monomer of cellulose is galactose. B) humans have enzymes that can hydrolyze the beta (β) glycosidic linkages of starch but not the alpha (α) glycosidic linkages of cellulose. C) humans have enzymes that can hydrolyze the alpha (α) glycosidic linkages of starch but not the beta (β) glycosidic linkages of cellulose. D) humans harbor starch-digesting bacteria in the digestive tract. E) the monomer of starch is glucose, while the monomer of cellulose is maltose.

humans have enzymes that can hydrolyze the alpha (α) glycosidic linkages of starch but not the beta (β) glycosidic linkages of cellulose.

What maintains the secondary structure of a protein? A) peptide bonds B) hydrogen bonds C) disulfide bonds D) ionic bonds E) phosphodiester bonds

hydrogen bonds

Which type of interaction stabilizes the alpha (α) helix and the beta (β) pleated sheet structures of proteins? A) hydrophobic interactions B) nonpolar covalent bonds C) ionic bonds D) hydrogen bonds E) peptide bonds

hydrogen bonds

A new organism is discovered in the forests of Costa Rica. Scientists there determine that the polypeptide sequence of hemoglobin from the new organism has 72 amino acid differences from humans, 65 differences from a gibbon, 49 differences from a rat, and 5 differences from a frog. These data suggest that the new organism A) is more closely related to humans than to frogs. B) is more closely related to frogs than to humans. C) may have evolved from gibbons but not rats. D) is more closely related to humans than to rats. E) may have evolved from rats but not from humans and gibbons

is more closely related to frogs than to humans.

Which of the following is a diverse group of hydrophobic molecules? A) carbohydrates B) lipids C) proteins D) nucleic acids

lipids

The element nitrogen is present in all of the following except A) proteins. B) nucleic acids. C) amino acids. D) DNA. E) monosaccharides

monosaccharides.

Which of the following store and transmit hereditary information? A) carbohydrates B) lipids C) proteins D) nucleic acids

nucleic acids

Which bonds are created during the formation of the primary structure of a protein? A) peptide bonds B) hydrogen bonds C) disulfide bonds D) phosphodiester bonds E) A, B, and C

peptide bonds

Enzymes are A) carbohydrates. B) lipids. C) proteins. D) nucleic acids

proteins