Examination #2

1) Which of the following is not one of the four major groups of macromolecules found in living organisms? A) glucose B) carbohydrates C) lipids D) proteins E) nucleic acids Topic: OverviewSkill: Knowledge

2) Polymers of polysaccharides, fats, and proteins are all synthesized from monomers by which process? A) connecting monosaccharides together (condensation reactions) B) the addition of water to each monomer (hydrolysis) C) the removal of water (dehydration reactions) D) ionic bonding of the monomers E) the formation of disulfide bridges between monomers Topic: Concept 5.1Skill: Comprehension

3) Which of the following best summarizes the relationship between dehydration reactions and hydrolysis? A) Dehydration reactions assemble polymers, and hydrolysis breaks down polymers. B) Hydrolysis only occurs in the urinary system, and dehydration reactions only occur in the digestive tract. C) Dehydration reactions can occur only after hydrolysis. D) Hydrolysis creates monomers, and dehydration reactions break down polymers. E) A and C are correct. Topic: Concept 5.2Skill: Comprehension

4) A molecule with the chemical formula C16H32O16

is probably a A) carbohydrate. B) lipid. C) protein. D) nucleic acid. E) hydrocarbon. Topic: Concept 5.2Skill: Comprehension

Figure 5.1

5) If 128 molecules of the general type shown in Figure 5.1 were covalently joined together in sequence, the single molecule that would result would be a A) polysaccharide. B) polypeptide. C) polyunsaturated lipid. D) monosaccharide. E) disaccharide. Topic: Concept 5.2Skill: Comprehension

6) Consider a polysaccharide consisting of 576 glucose molecules. The total hydrolysis of the polysaccharide would result in the production of A) 575 glucose molecules. B) 575 water molecules. C) 576 glucose molecules. D) A and B only E) B and C only Topic: Concept 5.2Skill: Comprehension

7) 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 Topic: Concept 5.2Skill: Comprehension

8) Which of the following are polysaccharides? A) glycogen B) starch C) chitin D) A and B only E) A, B, and C Topic: Concept 5.2

Skill: Knowledge

9) 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. Topic: Concept 5.2Skill: Knowledge

10) 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. Topic: Concept 5.2Skill: Knowledge

11) 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 ( ) glycosidic linkages of starch but not the βalpha ( ) glycosidic linkages of cellulose.α C) humans have enzymes that can hydrolyze the alpha ( ) glycosidic linkages of starch but not the αbeta ( ) glycosidic linkages of cellulose.β D) humans harbor starch-digesting bacteria in the digestive tract. E) the monomer of starch is glucose, while the monomer of cellulose is maltose. Answer: C Topic: Concept 5.2Skill: Comprehension

12) A molecule with the formula C18H36O2 is probably a A) carbohydrate. B) lipid. C) protein. D) nucleic acid. E) hydrocarbon. Topic: Concept 5.3Skill: Comprehension

13) Which of the following is (are) true for the class of large biological molecules known as lipids? A) They are insoluble in water. B) They are an important constituent of cell membranes. C) They contain twice as much energy as an equivalent weight of polysaccharide. D) Only A and B are correct. E) A, B, and C are correct. Topic: Concept 5.3Skill: Knowledge

14) Triacylglycerol is a A) protein with tertiary structure. B) lipid made with three fatty acids and glycerol. C) lipid that makes up much of the plasma membrane. D) molecule formed from three alcohols by dehydration reactions. E) carbohydrate with three sugars joined together by glycosidic linkages. Topic: Concept 5.3Skill: Knowledge

15) Saturated fatty acids A) are the predominant fatty acid in corn oil. B) have double bonds between carbon atoms of the fatty acids. C) have a higher ratio of hydrogen to carbon than do unsaturated fatty acids. D) are usually liquid at room temperature. E) are usually produced by plants. Answer: C Topic: Concept 5.3Skill: Knowledge

Figure 5.2

16) What is the molecule illustrated in Figure 5.2? A) a saturated fatty acid B) an unsaturated fatty acid C) a polyunsaturated triacylglyceride D) a trans polyunsaturated triacylglyceride E) a steroid similar to cholesterol Topic: Concept 5.3Skill: Knowledge

Figure 5.3

17) The molecule shown in Figure 5.3 is a A) polysaccharide. B) polypeptide. C) saturated fatty acid. D) triacylglycerol. E) unsaturated fatty acid. Topic: Concept 5.3Skill: Knowledge

18) The hydrogenation of vegetable oil would result in which of the following? A) a decrease in the number of carbon-carbon double bonds in the oil (fat) molecules B) an increase in the number of hydrogen atoms in the oil (fat) molecule C) the oil (fat) being a solid at room temperature D) A and C only E) A, B, and C Topic: Concept 5.3Skill: Comprehension

Figure 5.4

19) What is the structure shown in Figure 5.4? A) starch molecule B) protein molecule C) steroid molecule D) cellulose molecule E) phospholipid molecule Topic: Concept 5.3Skill: Knowledge

20) A polypeptide can best be described as a A) monomer of a protein polymer. B) polymer containing 20 amino acid molecules. C) polymer containing 19 peptide bonds. D) polymer containing 20 peptide bonds.

E) polymer of amino acids. Topic: Concept 5.4Skill: Knowledge

21) The 20 different amino acids found in polypeptides exhibit different chemical and physical properties because of different A) carboxyl groups attached to an alpha ( ) αcarbon B) amino groups attached to an alpha ( ) carbonα C) side chains (R groups). D) alpha ( ) carbons.α E) asymmetric carbons. Topic: Concept 5.4Skill: Knowledge

Figure 5.5

22) The chemical reaction illustrated in Figure 5.5 results in the formation of a (an) A) ionic bond. B) peptide bond. C) glycosidic linkage. D) ester linkage. E) phosphodiester linkage. Topic: Concept 5.4Skill: Comprehension

23) 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 Topic: Concept 5.4Skill: Comprehension

24) 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. Topic: Concepts 5.1-5.4Skill: Knowledge

25) 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 Topic: Concepts 5.1-5.4Skill: Knowledge

26) Upon chemical analysis, a particular protein was found to contain 556 amino acids. How many peptide bonds are present in this protein? A) 139 B) 554 C) 555 D) 556 E) 558 Topic: Concept 5.4Skill: Comprehension

Refer to Figure 5.6 to answer the following questions.

Figure 5.6

27) At which bond would water need to be added to achieve hydrolysis of the peptide, back to its component amino acid? Topic: Concept 5.4Skill: Comprehension

28) Which bond is closest to the N-terminus of the molecule? Topic: Concept 5.4

Skill: Comprehension

29) Which bond is closest to the C-terminus of the molecule? Topic: Concept 5.4Skill: Comprehension

30) How many different kinds of polypeptides, each composed of 12 amino acids, could be synthesized using the 20 common amino acids? A) 412 B) 1220 C) 125 D) 20 E) 2012 Topic: Concept 5.4Skill: Application

31) 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 Topic: Concept 5.4Skill: Knowledge

32) What maintains the secondary structure of a protein? A) peptide bonds B) hydrogen bonds C) disulfide bonds D) ionic bonds E) phosphodiester bonds Topic: Concept 5.4Skill: Knowledge

33) Which type of interaction stabilizes the alpha ( ) helix and the beta ( ) pleated sheet structures α βof proteins? A) hydrophobic interactions B) nonpolar covalent bonds C) ionic bonds D) hydrogen bonds E) peptide bonds Topic: Concept 5.4Skill: Knowledge

34) The helix and the pleated sheet are both α βcommon polypeptide forms found in which level of protein structure? A) primary B) secondary

C) tertiary D) quaternary E) all of the above Topic: Concept 5.4Skill: Knowledge

Figure 5.7

35) Figure 5.7 shows the A) 1-4 linkage of the glucose monomers of αstarch. B) 1-4 linkage of the glucose monomers of βcellulose. C) double helical structure of a DNA molecule. D) helix secondary structure of a polypeptide.α E) pleated sheet secondary structure of a βpolypeptide. Topic: Concept 5.4Skill: Comprehension

36) Figure 5.7 best illustrates the A) secondary structure of a polypeptide. B) tertiary structure of a polypeptide. C) quaternary structure of a protein. D) double helix structure of DNA. E) primary structure of a polysaccharide. Topic: Concept 5.4Skill: Comprehension

37) 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 αhelix or pleated sheet.β E) overall protein structure resulting from the aggregation of two or more polypeptide subunits. Topic: Concept 5.4Skill: Knowledge

38) A strong covalent bond between amino acids that functions in maintaining a polypeptide's specific three-dimensional shape is a (an) A) ionic bond. B) hydrophobic interaction. C) van der Waals interaction. D) disulfide bond. E) hydrogen bond. Topic: Concept 5.4Skill: Knowledge

39) 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 Topic: Concept 5.4Skill: Knowledge

40) The R group or side chain of the amino acid serine is –CH2-OH. 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. Topic: Concept 5.4Skill: Application

41) The globular protein transthyretin results from the aggregation of four polypeptide subunits. Each of the subunits is a polypeptide chain with an

helix region. Which structure(s) must the αtransthyretin protein have? A) primary structure B) primary and secondary structure

C) primary, secondary, and tertiary structure D) primary, secondary, tertiary, and quaternary structure E) primary, secondary, tertiary, quaternary, and alpha structure Topic: Concept 5.4Skill: Comprehension

42) 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. Topic: Concept 5.4Skill: Comprehension

43) 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 Topic: Concept 5.4Skill: Comprehension

44) All of the following molecules are proteins except A) hemoglobin. B) transthyretin. C) collagen. D) lysozyme. E) glycogen. Topic: Concept 5.4Skill: Knowledge

45) What is the term used for a change in a protein's 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 Topic: Concept 5.4Skill: Knowledge

46) 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 Topic: Concept 5.4Skill: Knowledge

47) 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 organisms. Topic: Concept 5.5Skill: Comprehension

48) 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 Topic: Concept 5.5Skill: Comprehension

49) 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 Topic: Concept 5.5Skill: Knowledge

50) 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 Answer: B Topic: Concept 5.5Skill: Knowledge

51) 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 Topic: Concept 5.5Skill: Knowledge

52) All of the following nitrogenous bases are found in DNA except A) thymine. B) adenine. C) uracil. D) guanine. E) cytosine. Topic: Concept 5.5Skill: Knowledge

53) A double-stranded DNA molecule contains a total of 120 purines and 120 pyrimidines. This DNA molecule could be comprised 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. Topic: Concept 5.5Skill: Application

54) 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. Topic: Concept 5.5Skill: Knowledge

55) 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. Topic: Concept 5.5Skill: Knowledge

56) In the double helix structure of nucleic acids, cytosine hydrogen bonds to A) deoxyribose. B) ribose. C) adenine. D) thymine. E) guanine. Topic: Concept 5.5Skill: Knowledge

57) The two strands making up the DNA double helix molecule A) cannot be separated. B) contain ribose and deoxyribose in opposite strands. C) are held together by hydrogen bonds. D) are attached through a phosphate to hold the strands together. E) contain uracil but not thymine. Topic: Concept 5.5Skill: Knowledge

58) If one strand of a DNA molecule has the sequence of bases 5'ATTGCA3', the other complementary strand would have the sequence A) 5'TAACGT3'. B) 3'TAACGT5'. C) 5'UAACGU3'. D) 3'UAACGU5'. E) 5'UGCAAU3'. Topic: Concept 5.5Skill: Knowledge

59) The structural feature that allows DNA to replicate is the 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 helix.α E) three-component structure of the nucleotides. Topic: Concept 5.5Skill: Knowledge

60) 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. Topic: Concept 5.5Skill: Application

61) 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 Topic: Concepts 5.1-5.4Skill: Comprehension

62) 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 Topic: Concepts 5.1-5.4Skill: Comprehension

63) The element nitrogen is present in all of the following except A) proteins. B) nucleic acids. C) amino acids. D) DNA. E) monosaccharides. Topic: Concepts 5.1-5.4Skill: Knowledge

The following questions are based on the 15 molecules illustrated in Figure 5.8. Each molecule may be used once, more than once, or not at all.

Figure 5.8

64) Which of the following molecules are structural isomers? A) 1 and 4 B) 5 and 14 C) 6 and 12 D) 12 and 13 E) 14 and 15 Topic: Concept 5.2Skill: Comprehension

65) Which of the following combinations could be linked together to form a nucleotide? A) 1, 2, and 11

B) 3, 7, and 8 C) 5, 9, and 10 D) 11, 12, and 13 E) 12, 14, and 15 Topic: Concept 5.5Skill: Comprehension

66) Which of the following molecules contain(s) an aldehyde type of carbonyl functional group? A) 1 B) 4 C) 8 D) 10 E) 1 and 4 Topic: Concept 5.2Skill: Comprehension

67) Which of the following molecules is (are) a carbohydrate? A) 1 and 4 B) 6 C) 12 D) 5 and 14 E) all of the above Topic: Concept 5.2Skill: Comprehension

68) Which of the following molecules is a saturated fatty acid? A) 1 B) 5 C) 6 D) 8 E) 9 Topic: Concept 5.3Skill: Knowledge

69) Which of the following molecules is a purine type of nitrogenous base? A) 2 B) 3 C) 5 D) 12 E) 13 Topic: Concept 5.5Skill: Knowledge

70) Which of the following molecules act as building blocks (monomers) of polypeptides? A) 1, 4, and 6 B) 2, 7, and 8 C) 7, 8, and 13 D) 11, 12, and 13 E) 12, 13, and 15 Topic: Concept 5.4

Skill: Knowledge

71) Which of the following molecules is an amino acid with a hydrophobic R group or side chain? A) 3 B) 5 C) 7 D) 8 E) 12 Topic: Concept 5.4Skill: Comprehension

72) Which of the following molecules could be joined together by a peptide bond as a result of a dehydration reaction? A) 2 and 3 B) 3 and 7 C) 7 and 8 D) 8 and 9 E) 12 and 13 Topic: Concept 5.4Skill: Comprehension

73) A fat (or triacylglycerol) would be formed as a result of a dehydration reaction between A) one molecule of 9 and three molecules of 10. B) three molecules of 9 and one molecule of 10. C) one molecule of 5 and three molecules of 9. D) three molecules of 5 and one molecule of 9. E) one molecule of 5 and three molecules of 10. Topic: Concept 5.3Skill: Comprehension

74) Which of the following molecules could be joined together by a phosphodiester type of covalent bond? A) 3 and 4 B) 3 and 8 C) 6 and 15 D) 11 and 12 E) 11 and 13 Topic: Concept 5.3Skill: Comprehension

75) Which of the following molecules is the pentose sugar found in RNA? A) 1 B) 4 C) 6 D) 12 E) 13 Topic: Concept 5.5Skill: Knowledge

76) Which of the following molecules contains a

glycosidic linkage type of covalent bond? A) 4 B) 6 C) 12 D) 13 E) 15 Topic: Concept 5.2Skill: Comprehension

77) Which of the following molecules has (have) a functional group that frequently is involved in maintaining the tertiary structure of a protein? A) 2 B) 3 C) 9 D) 11 E) 9 and 11 Answer: A Topic: Concept 5.4Skill: Comprehension

78) Which of the following molecules consists of a hydrophilic "head" region and a hydrophobic "tail" region? A) 2 B) 5 C) 7 D) 9 E) 11 Topic: Concept 5.3Skill: Knowledge

79) Which of the following statements is false? A) 1 and 4 could be joined together by a glycosidic linkage to form a disaccharide. B) 9 and 10 could be joined together by ester bonds to form a triacylglycerol. C) 2 and 7 could be joined together to form a short peptide. D) 2, 7, and 8 could be joined together to form a short peptide. E) 14 and 15 could be joined together to form a polypeptide. Topic: Concepts 5.2-5.4Skill: Comprehension

Media Activity Questions

80) Carbohydrates generally have a molecular formula A) that includes a -SH group. B) in which carbon, hydrogen, and oxygen are present in a ratio of 1:2:1.

C) that includes a -NH2 group. D) that includes at least one hydrocarbon tail. E) in which carbon, hydrogen, and oxygen are present in a 2:1:2 ratio. Answer: B Topic: Web/CD Activity: Carbohydrates

81) A function of cholesterol that does not harm health is its role A) in calcium and phosphate metabolism. B) as a component of animal cell membranes. C) as the primary female sex hormone. D) as the primary male sex hormone. E) None of the above; all of cholesterol's effects on the body are harmful. Answer: B Topic: Web/CD Activity: Lipids

82) Which of these does not contain a structural protein? A) muscles B) tendons C) ovalbumin D) spider silk E) ligaments Topic: Web/CD Activity: Protein Functions

83) The primary structure of a protein is A) an helix or a pleated sheet.α B) the amino acid sequence of the polypeptide chain. C) composed of two or more polypeptide chains. D) maintained by hydrogen bonds. E) irregular folding. Topic: Web/CD Activity: Protein Structure

84) Which of these is a difference between DNA and RNA? A) RNA is double-stranded; DNA is single-stranded. B) DNA is found in the nucleus; RNA is never found in the nucleus. C) In DNA, adenine pairs with guanine; in RNA, adenine pairs with thymine. D) DNA contains thymine; RNA contains uracil. E) DNA consists of five different nucleotides; RNA consists of four different nucleotides. Topic: Web/CD Activity: Nucleic Acid Structure

Self-Quiz Questions

85) Which term includes all others in the list? A) monosaccharide

B) disaccharide C) starch D) carbohydrate E) polysaccharide

86) The molecular formula for glucose is C6H12O6. What would be the molecular formula for a polymer made by linking ten glucose molecules together by dehydration reactions? A) C60H120O60

B) C60H12O6

C) C60H102O51

D) C60H100O50

E) C60H111O51

87) The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are the form. Which of the following αcould amylase break down? (Choose all that apply.) A) cellulose B) chitin C) glycogen D) starch E) amylopectin

88) Choose the pair of terms that correctly completes this sentence:Nucleotides are to ________ as ________ are to proteins. A) nucleic acids; amino acids B) amino acids; polypeptides C) glycosidic linkages; polypeptide linkages D) genes; enzymes E) polymers; polypeptides

89) Which of the following statements concerning unsaturated fats is true? A) They are more common in animals than in plants. B) They have 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 have fewer fatty acid molecules per fat molecule.

90) The structural level of a protein least affected by a disruption in hydrogen bonding is the A) primary level. B) secondary level. C) tertiary level. D) quaternary level. E) All structural levels are equally affected.

91) Which of the following pairs of base sequences could form a short stretch of a normal double helix of DNA? A) 5'-purine-pyrimidine-purine-pyrimidine-3' with 3'-purine-pyrimidine-purine-pyrimidine-5' B) 5'-A-G-C-T-3' with 5'-T-C-G-A-3' C) 5'-G-C-G-C-3' with 5'-T-A-T-A-3' D) 5'-A-T-G-C-3' with 5'-G-C-A-T-3' E) A, B, and D are all correct.

92) Enzymes that break down DNA catalyze the hydrolysis of the covalent bonds that join nucleotides together. What would happen to DNA molecules treated with these enzymes? 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.

93) Which of the following is not a protein? A) hemoglobin B) cholesterol C) an antibody D) an enzyme E) insulin

94) Which of the following statements about the 5' end of a polynucleotide strand is correct? A) The 5' end has a hydroxyl group. B) The 5' end has a phosphate group. C) The 5' end is identical to the 3' end. D) The 5' end is antiparallel to the 3' end. E) The 5' end is the fifth position on one of the nitrogenous bases.

16) Which of the following is true regarding deoxyribonucleic acid (DNA)?

A) Each deoxyribonucleic acid molecule is composed of two long chains of nucleotides arranged in a double helix. B) Genes are composed of deoxyribonucleic acid. C) DNA is composed of chemical building blocks called nucleotides. D) Only A and C are correct. E) A, B, and C are correct. Topic: Concept 1.1

Skill: Knowledge

17) What are the basic "building blocks" of deoxyribonucleic acid (DNA)? A) 100,000 different kinds of proteins B) 26 different kinds of chromosomes C) 20 different kinds of amino acids D) 4 different kinds of nucleotides E) 3 different kinds of genomes Topic: Concept 1.1Skill: Knowledge

18) Which of the following types of cells utilize deoxyribonucleic acid (DNA) as their genetic material? A) animal B) plant C) archaea D) A and B only E) A, B, and C Topic: Concept 1.1Skill: Comprehension

21) In order to understand the chemical basis of inheritance, one must understand the molecular structure of DNA. This is an example of the application of ________ to the study of biology.

A) evolution B) emergent properties C) reductionism D) the cell theory E) feedback regulation Topic: Concept 1.2Skill: Comprehension

22) The chemical reactions within cells are regulated by organic catalysts called A) feedback activators. B) feedback inhibitors. C) enzymes. D) metabolites. E) nutrients. Topic: Concept 1.2Skill: Knowledge

23) Once labor begins in childbirth, contractions increase in intensity and frequency until delivery. The increasing labor contractions of childbirth are an example of A) a bioinformatic system. B) positive feedback. C) negative feedback.

D) feedback inhibition. E) both C and D Topic: Concept 1.2Skill: Comprehension

24) When blood glucose level rises, the pancreas secretes insulin, and as a result blood glucose level declines. When blood glucose level is low, the pancreas secretes glucagon, and as a result blood glucose level rises. Such regulation of blood glucose level is the result of A) catalytic feedback. B) positive feedback. C) negative feedback. D) bioinformatic regulation. E) both A and B Topic: Concept 1.2Skill: Comprehension

Metabolism & Enzymes

1) Which of the following describe(s) some aspect of metabolism? A) synthesis of macromolecules B) breakdown of macromolecules C) control of enzyme activity D) A and B only E) A, B, and C Topic: Concept 8.1Skill: Knowledge

2) Which term most precisely describes the cellular process of breaking down large molecules into smaller ones? A) catalysis B) metabolism C) anabolism D) dehydration E) catabolism Topic: Concept 8.1Skill: Knowledge

3) Which of the following statements correctly describe(s) catabolic pathways? A) They do not depend on enzymes. B) They consume energy to build up polymers from monomers. C) They release energy as they degrade polymers to monomers. D) They lead to the synthesis of catabolic compounds. E) both A and B Topic: Concept 8.1Skill: Knowledge

4) Which of the following is (are) true for anabolic pathways? A) They do not depend on enzymes. B) They are highly regulated sequences of chemical reactions. C) They consume energy to build up polymers from monomers. D) They release energy as they degrade polymers to monomers. E) both B and C Topic: Concept 8.1Skill: Knowledge

5) Which of the following is a statement of the first law of thermodynamics? A) Energy cannot be created or destroyed. B) The entropy of the universe is decreasing. C) The entropy of the universe is constant. D) Kinetic energy is stored energy that results

from the specific arrangement of matter. E) Energy cannot be transferred or transformed. Topic: Concept 8.1Skill: Knowledge

6) The first law of thermodynamics states that energy can be neither created nor destroyed. For living organisms, which of the following is an important consequence of the first law? A) The energy content of an organism is constant. B) The organism ultimately must obtain all of the necessary energy for life from its environment. C) The entropy of an organism decreases with time as the organism grows in complexity. D) Organisms are unable to transform energy. E) Life does not obey the first law of thermodynamics. Topic: Concept 8.1Skill: Application

7) According to the first law of thermodynamics, A) the universe loses energy because of heat production. B) systems rich in energy are intrinsically unstable and will give up energy with time. C) energy can be neither created nor destroyed. D) A and B only E) A, B, and C Topic: Concept 8.1Skill: Comprehension

8) Living organisms increase in complexity as they grow, resulting in a decrease in the entropy of an organism. How does this relate to the second law of thermodynamics? A) Living organisms do not obey the second law of thermodynamics, which states that entropy must increase with time. B) Life obeys the second law of thermodynamics because the decrease in entropy as the organism grows is balanced by an increase in the entropy of the universe. C) Living organisms do not follow the laws of thermodynamics. D) As a consequence of growing, organisms create more disorder in their environment than the decrease in entropy associated with their growth. E) Living organisms are able to transform energy into entropy. Topic: Concept 8.1Skill: Application

9) Which of the following statements about metabolism is incorrect? A) Metabolism is an emergent property of life at

the level of organisms. B) Metabolism manages the utilization of materials and energy resources. C) The uptake of water associated with the hydrolysis of biological polymers is part of metabolism. D) Metabolism depends on a constant supply of energy. E) None of these statements about metabolism is incorrect. Topic: Concept 8.1Skill: Comprehension

10) Whenever energy is transformed, there is always an increase in the A) free energy of the system. B) free energy of the universe. C) entropy of the system. D) entropy of the universe. E) enthalpy of the universe. Topic: Concept 8.1Skill: Comprehension

11) Which of the following statements is a logical consequence of the second law of thermodynamics? A) If the entropy of a system increases, there must be a corresponding decrease in the entropy of the universe. B) If there is an increase in the energy of a system, there must be a corresponding decrease in the energy of the rest of the universe. C) Every energy transfer requires activation energy from the environment. D) Every chemical reaction must increase the total entropy of the universe. E) Energy can be transferred or transformed, but it cannot be created or destroyed. Topic: Concept 8.1Skill: Comprehension

12) Which of the following statements correctly describe(s) some aspect of energy in living organisms? A) Living organisms can convert energy among several different forms. B) Living organisms can use energy to do work. C) Organisms expend energy in order to decrease their entropy D) A and B only E) A, B, and C Topic: Concept 8.1Skill: Comprehension

13) Which of the following statements is not

representative of the second law of thermodynamics? A) Conversion of energy from one form to another is always accompanied by some loss of free energy. B) Heat represents a form of energy that cannot be used by most organisms to do work. C) Without an input of energy, organisms would tend towards increasing entropy. D) Cells require a constant input of energy to maintain their high level of organization. E) Every energy transformation by a cell decreases the entropy of the universe. Topic: Concept 8.1Skill: Comprehension

16) According to the second law of thermodynamics, which of the following statements is incorrect? A) The synthesis of large molecules from small molecules is exergonic. B) Earth is an open system. C) Life exists at the expense of energy derived from its environment. D) A living cell can never function as a closed system. E) Every chemical reaction in a cell results in a loss of free energy. Topic: Concept 8.1Skill: Comprehension

17) The organization of organisms has become increasingly complex with time. This statement A) is consistent with the second law of thermodynamics. B) requires that due to evolution, the entropy of the universe increased. C) is based on the fact that organisms function as closed systems. D) A and B only E) A, B, and C Topic: Concept 8.1Skill: Comprehension

18) The mathematical expression for the change in free energy of a system is: ΔG = ΔH - T SΔ . Which of the following is (are) incorrect? A) ΔS is the change in entropy, a measure of randomness. B) ΔH is the change in enthalpy, the energy available to do work. C) ΔG is the change in free energy. D) T is the absolute temperature. E) both A and B

Topic: Concept 8.2Skill: Knowledge

19) What is the change in free energy of a system at chemical equilibrium? A) slightly increasing B) greatly increasing C) slightly decreasing D) greatly decreasing E) no net change Topic: Concept 8.2Skill: Knowledge

20) Which of the following is true for all exergonic reactions? A) The products have more total energy than the reactants. B) The reaction proceeds with a net release of free energy. C) Some reactants will be converted to products. D) A net input of energy from the surroundings is required for the reactions to proceed. E) The reactions are nonspontaneous. Topic: Concept 8.2Skill: Comprehension

21) Chemical equilibrium is relatively rare in living cells. Which of the following could be an example of a reaction at chemical equilibrium in a cell? A) a reaction in which the free energy at equilibrium is higher than the energy content at any point away from equilibrium B) a chemical reaction in which the entropy change in the reaction is just balanced by an opposite entropy change in the cell's surroundings C) an endergonic reaction in an active metabolic pathway where the energy for that reaction is supplied only by heat from the environment D) a chemical reaction in which both the reactants and products are only used in a metabolic pathway that is completely inactive E) There is no possibility of having chemical equilibrium in any living cell. Topic: Concept 8.2Skill: Application

22) Which of the following shows the correct changes in thermodynamic properties for a chemical reaction in which amino acids are linked to form a protein? A) +ΔH, + S, + GΔ Δ B) +ΔH, - S, - GΔ Δ C) +ΔH, - S, + GΔ Δ D) -ΔH, - S, + GΔ Δ

E) -ΔH, + S, + GΔ Δ Topic: Concept 8.2Skill: Comprehension

23) When glucose monomers are joined together by glycosidic linkages to form a cellulose polymer, the changes in free energy, total energy, and entropy are as follows: A) +ΔG, + H, + SΔ Δ B) +ΔG, + H, - SΔ Δ C) +ΔG, - H, - SΔ Δ D) -ΔG, + H, + SΔ Δ E) -ΔG, - H, - SΔ Δ Topic: Concept 8.2Skill: Comprehension

24) A chemical reaction that has a positive ΔG is correctly described as A) endergonic. B) endothermic. C) enthalpic. D) spontaneous. E) exothermic. Topic: Concept 8.2Skill: Knowledge

31) What term is used to describe the transfer of free energy from catabolic pathways to anabolic pathways? A) feedback regulation B) bioenergetics C) energy coupling D) entropy E) cooperativity Topic: Concept 8.3Skill: Knowledge

32) Which of the following statements is true concerning catabolic pathways? A) They combine molecules into more energy-rich molecules. B) They are usually coupled with anabolic pathways to which they supply energy in the form of ATP. C) They are endergonic. D) They are spontaneous and do not need enzyme catalysis. E) They build up complex molecules such as protein from simpler compounds. Topic: Concept 8.3Skill: Comprehension

35) How can one increase the rate of a chemical

reaction? A) Increase the activation energy needed. B) Cool the reactants. C) Decrease the concentration of the reactants. D) Add a catalyst. E) Increase the entropy of the reactants. Topic: Concept 8.4Skill: Comprehension

36) Sucrose is a disaccharide, composed of the monosaccharides glucose and fructose. The hydrolysis of sucrose by the enzyme sucrase results in A) bringing glucose and fructose together to form sucrose. B) the release of water from sucrose as the bond between glucose and fructose is broken. C) breaking the bond between glucose and fructose and forming new bonds from the atoms of water. D) production of water from the sugar as bonds are broken between the glucose monomers. E) utilization of water as a covalent bond is formed between glucose and fructose to form sucrase. Topic: Concept 8.4Skill: Application

37) Reactants capable of interacting to form products in a chemical reaction must first overcome a thermodynamic barrier known as the reaction's A) entropy. B) activation energy. C) endothermic level. D) heat content. E) free-energy content. Topic: Concept 8.4Skill: Knowledge

38) A solution of starch at room temperature does not readily decompose to form a solution of simple sugars because A) the starch solution has less free energy than the sugar solution. B) the hydrolysis of starch to sugar is endergonic. C) the activation energy barrier for this reaction cannot be surmounted. D) starch cannot be hydrolyzed in the presence of so much water. E) starch hydrolysis is nonspontaneous. Topic: Concept 8.4Skill: Comprehension

39) Which of the following statements regarding

enzymes is true? A) Enzymes decrease the free energy change of a reaction. B) Enzymes increase the rate of a reaction. C) Enzymes change the direction of chemical reactions. D) Enzymes are permanently altered by the reactions they catalyze. E) Enzymes prevent changes in substrate concentrations. Topic: Concept 8.4Skill: Knowledge

40) Which of the following is not true of enzymes? A) Enzyme catalysis is dependent on the pH and temperature of the reaction environment. B) Enzyme catalysis is dependent on the three-dimensional structure or conformation of the enzyme. C) Enzymes provide activation energy for the reaction they catalyze. D) Enzymes are composed primarily of protein, but they may bind nonprotein cofactors. E) Enzyme activity can be inhibited if the enzyme's allosteric site is bound with a noncompetitive inhibitor. Topic: Concept 8.4Skill: Knowledge

41) An enzyme catalyzes a reaction by A) supplying the energy to speed up a reaction. B) lowering the energy of activation of a reaction. C) lowering the ΔG of a reaction. D) changing the equilibrium of a spontaneous reaction. E) increasing the amount of free energy of a reaction. Topic: Concept 8.4Skill: Knowledge

42) Which of these statements regarding enzymes is false? A) Enzymes are proteins that function as catalysts. B) Enzymes display specificity for certain molecules with which they interact. C) Enzymes provide activation energy for the reactions they catalyze. D) The activity of enzymes can be regulated by other molecules. E) An enzyme may be used many times over for a specific reaction. Topic: Concept 8.4Skill: Knowledge

43) During a laboratory experiment, you discover

that an enzyme-catalyzed reaction has a ΔG of -20 kcal/mol. If you double the amount of enzyme in the reaction, what will be the G for the new Δreaction? A) -40 kcal/mol B) -20 kcal/mol C) 0 kcal/mol D) +20 kcal/mol E) +40 kcal/mol Topic: Concept 8.4Skill: Comprehension

44) The active site of an enzyme is the region that A) binds allosteric regulators of the enzyme. B) is involved in the catalytic reaction of the enzyme. C) binds the products of the catalytic reaction. D) is inhibited by the presence of a coenzyme or a cofactor. E) both A and B Topic: Concept 8.4Skill: Knowledge

45) According to the induced fit hypothesis of enzyme catalysis, which of the following is CORRECT? A) The binding of the substrate depends on the shape of the active site. B) Some enzymes change their structure when activators bind to the enzyme. C) A competitive inhibitor can outcompete the substrate for the active site. D) The binding of the substrate changes the shape of the enzyme's active site. E) The active site creates a microenvironment ideal for the reaction. Topic: Concept 8.4Skill: Comprehension

46) Many different things can alter enzyme activity. Which of the following underlie all types of enzyme regulation? A) changes in the activation energy of the reaction B) changes in the active site of the enzyme C) changes in the free energy of the reaction D) A and B only E) A, B, and C Topic: Concept 8.4Skill: Application

Refer to Figure 8.1 to answer the following questions.

Figure 8.1

47) Which curve represents the behavior of an enzyme taken from a bacterium that lives in hot springs at temperatures of 70°C or higher? A) curve 1 B) curve 2 C) curve 3 D) curve 4 E) curve 5 Topic: Concept 8.4Skill: Knowledge

48) Which curve was most likely generated from analysis of an enzyme from a human stomach where conditions are strongly acid? A) curve 1 B) curve 2 C) curve 3 D) curve 4 E) curve 5 Topic: Concept 8.4Skill: Knowledge

49) Which curve was most likely generated from an enzyme that requires a cofactor? A) curve 1 B) curve 2 C) curve 4 D) curve 5

E) It is not possible to determine whether an enzyme requires a cofactor from these data. Topic: Concept 8.4Skill: Comprehension

50) As temperature decreases, the rate of an enzyme-catalyzed reaction also decreases. Which of the following explain(s) why this occurs? A) Fewer substrates have sufficient energy to get over the activation energy barrier. B) Motion in the active site of the enzyme is slowed, thus slowing the catalysis of the enzyme. C) The motion of the substrate molecules decreases, allowing them to bind more easily to the active site. D) A and B only E) A, B, and C Topic: Concept 8.4Skill: Application

51) ATP is often an allosteric inhibitor of key enzymes in catabolic pathways. Which of the following statements is inconsistent with the role of ATP? A) ATP couples energy production in catabolic pathways to energy demand in anabolic pathways. B) When ATP levels are high in the cell, it is an indication that energy supply from catabolic reactions exceeds energy demand by anabolic reactions. C) The binding of ATP to allosteric sites on enzymes of the catabolic pathway decreases the production of ATP by the pathway. D) Increasing availability of ATP increases the energy available to drive endergonic reactions. E) When ATP levels are low in the cell, there is no inhibition of the catabolic pathway and ATP production is at a maximum. Topic: Concept 8.4Skill: Application

52) Increasing the substrate concentration in an enzymatic reaction could overcome which of the following? A) denaturization of the enzyme B) allosteric inhibition C) competitive inhibition D) saturation of the enzyme activity E) insufficient cofactors Topic: Concept 8.4Skill: Comprehension

53) What is a nonprotein "helper" of an enzyme molecule called? A) accessory enzyme

B) allosteric group C) coenzyme D) functional group E) enzyme activator Topic: Concept 8.4Skill: Knowledge

54) Which of the following is true of enzymes? A) Enzymes may require a nonprotein cofactor or ion for catalysis to take place. B) Enzyme function is reduced if the three-dimensional structure or conformation of an enzyme is altered. C) Enzyme function is influenced by physical and chemical environmental factors such as pH and temperature. D) Enzymes increase the rate of chemical reaction by lowering activation energy barriers. E) All of the above are true of enzymes. Topic: Concept 8.4Skill: Knowledge

55) Zinc, an essential trace element for most organisms, is present in the active site of the enzyme carboxypeptidase. The zinc most likely functions as a(n) A) competitive inhibitor of the enzyme. B) noncompetitive inhibitor of the enzyme. C) allosteric activator of the enzyme. D) cofactor necessary for enzyme activity. E) coenzyme derived from a vitamin. Topic: Concept 8.4Skill: Knowledge

56) Consider the following: Succinate dehydrogenase catalyzes the conversion of succinate to fumarate. The reaction is inhibited by malonic acid, which resembles succinate but cannot be acted upon by succinate dehydrogenase. Increasing the ratio of succinate to malonic acid reduces the inhibitory effect of malonic acid. Which of the following is correct? A) Succinate dehydrogenase is the enzyme, and fumarate is the substrate. B) Succinate dehydrogenase is the enzyme, and malonic acid is the substrate. C) Succinate is the substrate, and fumarate is the product. D) Fumarate is the product, and malonic acid is a noncompetitive inhibitor. E) Malonic acid is the product, and fumarate is a competitive inhibitor. Topic: Concept 8.4Skill: Comprehension

The following questions are based on the reaction A + B → C + D shown in Figure 8.2

Figure 8.2

57) Which of the following terms best describes the reaction? A) endergonic B) exergonic C) anabolic D) allosteric E) nonspontaneous Topic: Concept 8.4Skill: Knowledge

58) Which of the following represents the ΔG of the reaction? A) a B) b C) c D) d E) e Topic: Concept 8.4Skill: Knowledge

59) Which of the following would be the same in an enzyme-catalyzed or noncatalyzed reaction? A) a B) b C) c D) d E) e Topic: Concept 8.4Skill: Comprehension

60) Which of the following bests describes the reaction? A) negative ΔG, spontaneous B) positive ΔG, nonspontaneous

C) positive ΔG, exergonic D) negative ΔG, endergonic E) ΔG of zero, chemical equilibrium Topic: Concept 8.4Skill: Comprehension

61) Which of the following represents the difference between the free-energy content of the reaction and the free-energy content of the products? A) a B) b C) c D) d E) e Topic: Concept 8.4Skill: Knowledge

62) Which of the following represents the activation energy required for the enzyme-catalyzed reaction? A) a B) b C) c D) d E) e Topic: Concept 8.4Skill: Comprehension

63) Which of the following represents the activation energy required for a noncatalyzed reaction? A) a B) b C) c D) d E) e Topic: Concept 8.4Skill: Knowledge

64) Which best describes the reaction? A) The amount of free energy initially present in the reactants is indicated by "a." B) The amount of free energy present in the products is indicated by "e." C) The amount of free energy released as a result of the noncatalyzed reaction is indicated by "c." D) The amount of free energy released as a result of the catalyzed reaction is indicated by "d." E) The difference between "b" and "c" is the activation energy added by the presence of the enzyme. Topic: Concept 8.4Skill: Comprehension

65) Assume that the reaction has a ΔG of -5.6 kcal/mol. Which of the following would be true? A) The reaction could be coupled to power an endergonic reaction with a ΔG of +6.2 kcal/mol. B) The reaction could be coupled to power an exergonic reaction with a ΔG of +8.8 kcal/mol. C) The reaction would result in a decrease in entropy (S) and an increase in the total energy content (H) of the system. D) The reaction would result in an increase in entropy (S) and a decrease in the total energy content (H) of the system. E) The reaction would result in products (C + D) with a greater free-energy content than in the initial reactants (A + B).Topic: Concept 8.4Skill: Comprehension

The next questions are based on the following information.

A series of enzymes catalyze the reaction X→Y→Z→A. Product A binds to the enzyme that converts X to Y at a position remote from its active site. This binding decreases the activity of the enzyme.

66) What is substance X? A) a coenzyme B) an allosteric inhibitor C) a substrate D) an intermediate E) the product Topic: Concept 8.5Skill: Comprehension

67) Substance A functions as A) a coenzyme. B) an allosteric inhibitor. C) the substrate. D) an intermediate. E) a competitive inhibitor. Answer: B Topic: Concept 8.5Skill: Comprehension

68) The mechanism in which the end product of a metabolic pathway inhibits an earlier step in the pathway is known as A) metabolic inhibition. B) feedback inhibition. C) allosteric inhibition. D) noncooperative inhibition. E) reversible inhibition. Topic: Concept 8.5

Skill: Knowledge

69) The regulation of enzyme function is an important aspect of cell metabolism. Which of the following is least likely to be a mechanism for enzyme regulation? A) allosteric regulation B) cooperativity C) feedback inhibition D) removing cofactors E) reversible inhibition Topic: Concept 8.5Skill: Comprehension

70) Which of the following statements is true regarding enzyme cooperativity? A) A multi-enzyme complex contains all the enzymes of a metabolic pathway. B) A product of a pathway serves as a competitive inhibitor of an early enzyme in the pathway. C) A substrate molecule bound to an active site affects the active site of several subunits. D) Several substrate molecules can be catalyzed by the same enzyme. E) A substrate binds to an active site and inhibits cooperation between enzymes in a pathway. Topic: Concept 8.5Skill: Knowledge

71) How does a non-competitive inhibitor decrease the rate of an enzyme reaction? A) by binding at the active site of the enzyme B) by changing the structure of the enzyme C) by changing the free energy change of the reaction D) by acting as a coenzyme for the reaction E) by decreasing the activation energy of the reaction Topic: Concept 8.5Skill: Knowledge

Use Figure 8.3 to answer the following questions.

Figure 8.3

72) Which of the following statements correctly indicate(s) the role of ATP or ADP as an allosteric regulator? Assume that the supply of energy for cellular processes is adjusted to meet cellular demand for energy. A) ATP is an allosteric inhibitor of catabolic pathways. B) ADP is an allosteric activator of catabolic pathways. C) ATP is an allosteric activator of anabolic pathways. D) A and B only E) A, B, and C Topic: Concept 8.5Skill: Application

73) An increase in the level of cellular ATP is likely to occur under which of the following conditions? A) increased activity of catabolic pathways B) decreased activity of anabolic pathways C) allosteric inhibition of anabolic pathways D) A and B only E) A, B, and C Topic: Concept 8.5Skill: Comprehension