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Campbell's Biology, 9e (Reece et al.)
Chapter 5 The Structure and Function of Large Biological Molecules
In Chapter 5, the principles of chemistry covered in earlier chapters are applied to the understanding of
biological polymers and lipid membranes. The emphasis is on properly linking monomers and their
polymers, and on the structural and functional diversity of the different polymer types. Particular
attention is given to protein structure, because this is central to understanding subsequent chapters on
metabolism, molecular biology, and molecular medicine.
Multiple-Choice Questions
1) Humans and mice differ because
A) their cells have different small organic molecules.
B) their cells make different types of large biological molecules.
C) their cells make different types of lipids.
D) their cells have some differences in the sequence of nucleotides in their nucleic acids.
E) their cells make different types of proteins.
2) Molecules with which functional groups may form polymers via dehydration reactions?
A) hydroxyl groups
B) carbonyl groups
C) carboxyl groups
D) either carbonyl or carboxyl groups
E) either hydroxyl or carboxyl groups
3) Which of these molecules is not formed by dehydration reactions?
A) fatty acids
B) disaccharides
C) DNA
D) protein
E) amylose
4) In animal metabolism, most of the monomers released by digestion of food macromolecules are
metabolized to provide energy. Only a small portion of these monomers are used for synthesis of new
macromolecules. The net result is that
A) water is generated by animal metabolism.
B) water is consumed by animal metabolism.
C) the water consumed is exactly balanced by the water generated, to maintain homeostasis.
D) water is consumed during homeostasis, but water is generated during periods of growth.
E) water is generated during homeostasis, but water is consumed during periods of growth.
5) Which of these classes of biological molecules consist of both small molecules and macromolecular
polymers?
A) lipids
B) carbohydrates
C) proteins
D) nucleic acids
E) lipids, carbohydrates, proteins, and nucleic acids all consist of only macromolecular polymers
6) Which of the following is not a polymer?
A) glucose
B) starch
C) cellulose
D) chitin
E) DNA
7) What is the chemical reaction 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
8) 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
9) 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) Dehydration reactions eliminate water from lipid membranes, and hydrolysis makes lipid membranes
water permeable.
C) Dehydration reactions can occur only after hydrolysis.
D) Hydrolysis creates monomers, and dehydration reactions break down polymers.
E) Dehydration reactions ionize water molecules and add hydroxyl groups to polymers; hydrolysis
reactions release hydroxyl groups from polymers.
10) Which of the following polymers contain nitrogen?
A) starch
B) glycogen
C) cellulose
D) chitin
E) amylopectin
11) 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) C18H32O16
C) C6H10O5
D) C18H10O15
E) C3H6O3
12) 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) glycogen and chitin only
E) glycogen, cellulose, and chitin
13) On food packages, to what does the term insoluble fiber refer?
A) cellulose
B) polypeptides
C) starch
D) amylopectin
E) chitin
14) A molecule with the chemical formula C6H12O6 is probably a
A) carbohydrate.
B) lipid.
C) monosaccharide
D) carbohydrate and lipid only.
E) carbohydrate and monosaccharide only.
15) 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
16) All of the following are polysaccharides except
A) lactose.
B) glycogen.
C) chitin.
D) cellulose.
E) amylopectin.
17) Which of the following is true of both starch and cellulose?
A) They are both polymers of glucose.
B) They are cis-trans 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.
18) Which of the following is true of cellulose?
A) It is a polymer composed of enantiomers of glucose.
B) It is a storage polysaccharide for energy in plant cells.
C) It is digestible by bacteria in the human gut.
D) It is a major structural component of plant cell walls.
E) It is a polymer composed of enantiomers of glucose, it is a storage polysaccharide for energy in plant
cells, it is digestible by bacteria in the human gut, and it is a major structural component of plant cell
walls.
19) 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 β glycosidic linkages of starch but not the α glycosidic
linkages of cellulose.
C) humans have enzymes that can hydrolyze the α glycosidic linkages of starch but not the 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 glucose with a nitrogen-
containing group.
20) Which of the following statements concerning saturated fats is not true?
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 unsaturated fats having the same number of carbon atoms.
E) They are one of several factors that contribute to atherosclerosis.
21) A molecule with the formula C18H36O2 is probably a
A) carbohydrate.
B) fatty acid.
C) protein.
D) nucleic acid.
E) hydrocarbon.
22) Which of the following statements is true for the class of biological molecules known as lipids?
A) They are insoluble in water.
B) They are made from glycerol, fatty acids, and phosphate.
C) They contain less energy than proteins and carbohydrates.
D) They are made by dehydration reactions.
E) They contain nitrogen.
23) The label on a container of margarine lists "hydrogenated vegetable oil" as the major ingredient.
What is the result of adding hydrogens to vegetable oil?
A) The hydrogenated vegetable oil has a lower melting point.
B) The hydrogenated vegetable oil stays solid at room temperature.
C) The hydrogenated vegetable oil has more "kinks" in the fatty acid chains.
D) The hydrogenated vegetable oil has fewer trans fatty acids.
E) The hydrogenated vegetable oil is less likely to clog arteries.
24) 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.
25) 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
26) Which modifications of fatty acids will best keep triglycerides solid at warmer temperatures?
A) creating cis double bonds to the fatty acids
B) adding hydrogens to the fatty acids
C) creating trans double bonds to the fatty acids
D) adding hydrogens and trans double bonds to the fatty acids
E) adding cis double bonds and trans double bonds to the fatty acids
27) Why are human sex hormones considered to be lipids?
A) They are essential components of cell membranes.
B) They are not soluble in water.
C) They are made of fatty acids.
D) They are hydrophilic compounds.
E) They contribute to atherosclerosis.
28) All of the following contain amino acids except
A) hemoglobin.
B) cholesterol.
C) antibodies.
D) enzymes.
E) insulin.
29) 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) the release of a nitrous oxide molecule.
30) There are 20 different amino acids. What makes one amino acid different from another?
A) different side chains (R groups) attached to a carboxyl carbon
B) different side chains (R groups) attached to the amino groups
C) different side chains (R groups) attached to an α carbon
D) different structural and optical isomers
E) different asymmetric carbons
31) 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 a glycosidic bond
D) formation of a hydrogen bond
E) both removal of a water molecule and formation of a hydrogen bond
32) Polysaccharides, triacylglycerides, and proteins are similar in that they
A) are synthesized from monomers by the process of hydrolysis.
B) are synthesized from subunits 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.
33) Dehydration reactions are used in forming which of the following compounds?
A) triacylglycerides
B) polysaccharides
C) proteins
D) triacylglycerides and proteins only
E) triacylglycerides, polysaccharides, and proteins
34) 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
35) What aspects of protein structure are stabilized or assisted by hydrogen bonds?
A) primary structure
B) secondary structure
C) tertiary structure
D) quaternary structure
E) secondary, tertiary, and quaternary structures, but not primary structure
36) 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) 240
D) 20
E) 2012
37) 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) peptide bonds, hydrogen bonds, and disulfide bonds
38) What maintains the secondary structure of a protein?
A) peptide bonds
B) hydrogen bonds between the amino group of one peptide bond and the carboxyl group of another
peptide bond
C) disulfide bonds
D) hydrophobic interactions
E) hydrogen bonds between the R groups
39) Which type of interaction stabilizes the α helix and the β pleated sheet structures of proteins?
A) hydrophobic interactions
B) disulfide bonds
C) ionic bonds
D) hydrogen bonds
E) peptide bonds
40) Which level of protein structure do the α helix and the β pleated sheet represent?
A) primary
B) secondary
C) tertiary
D) quaternary
E) primary, secondary, tertiary, and quaternary
41) The amino acids of the protein keratin are arranged predominantly in an α helix. This secondary
structure is stabilized by
A) covalent bonds.
B) peptide bonds.
C) ionic bonds.
D) polar bonds.
E) hydrogen bonds.
42) 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.
43) What type of covalent bond between amino acid side chains (R groups) functions in maintaining a
polypeptide's specific three-dimensional shape?
A) ionic bond
B) hydrophobic interaction
C) van der Waals interaction
D) disulfide bond
E) hydrogen bond
44) 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
45) The R group or side chain of the amino acid serine is –CH2–OH. The R group or side chain of the
amino acid leucine is –CH2–CH–(CH3)2. Where would you expect to find these amino acids in a
globular protein in aqueous solution?
A) Serine would be in the interior, and leucine would be on the exterior of the globular protein.
B) Leucine would be in the interior, and serine would be on the exterior of the globular protein.
C) Both serine and leucine would be in the interior of the globular protein.
D) Both serine and leucine would be on the exterior of the globular protein.
E) Both serine and leucine would be in the interior and on the exterior of the globular protein.
46) Misfolding of polypeptides is a serious problem in cells. Which of the following diseases are
associated with an accumulation of misfolded polypeptides?
A) Alzheimer's only
B) Parkinson's only
C) diabetes mellitus only
D) Alzheimer's and Parkinson's only
E) Alzheimer's, Parkinson's, and diabetes mellitus
47) Changing a single amino acid in a protein consisting of 325 amino acids would
A) alter the primary structure of the protein, but not its tertiary structure or function.
B) cause the tertiary structure of the protein to unfold.
C) always alter the biological activity or function of the protein.
D) always alter the primary structure of the protein and disrupt its biological activity.
E) always alter the primary structure of the protein, sometimes alter the tertiary structure of the protein,
and affect its biological activity.
48) Normal hemoglobin is a tetramer, consisting of two molecules of β hemoglobin and two molecules
of α hemoglobin. In sickle-cell disease, as a result of a single amino acid change, the mutant hemoglobin
tetramers associate with each other and assemble into large fibers. Based on this information alone, we
can conclude that sickle-cell hemoglobin exhibits
A) altered primary structure.
B) altered secondary structure.
C) altered tertiary structure.
D) altered quaternary structure.
E) altered primary structure and altered quaternary structure; the secondary and tertiary structures may
or may not be altered.
49) What methods may be used to elucidate the structures of purified proteins?
A) X-ray crystallography
B) bioinformatics
C) analysis of amino acid sequence of small fragments
D) NMR spectroscopy
E) both X-ray crystallography and NMR spectroscopy
50) In a normal cellular protein, where would you expect to find a hydrophobic amino acid like valine?
A) in the interior of the folded protein, away from water
B) on the exterior surface of the protein, interacting with water
C) in the transmembrane portion interacting with lipid fatty acid chains
D) in the interior of the folded protein, away from water, or in a transmembrane portion interacting with
lipid fatty acid chains
E) anywhere in the protein, with equal probability
51) Which of the following techniques uses the amino acid sequences of polypeptides to predict a
protein's 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
52) If cells are grown in a medium containing radioactive 35S, which of these molecules will be
labeled?
A) phospholipids
B) nucleic acids
C) proteins
D) amylose
E) both proteins and nucleic acids
53) 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
54) 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.
55) Which of the following statements about the 5' end of a polynucleotide strand of DNA is correct?
A) The 5' end has a hydroxyl group attached to the number 5 carbon of ribose.
B) The 5' end has a phosphate group attached to the number 5 carbon of ribose.
C) The 5' end has phosphate attached to the number 5 carbon of the nitrogenous base.
D) The 5' end has a carboxyl group attached to the number 5 carbon of ribose.
E) The 5' end is the fifth position on one of the nitrogenous bases.
56) One of the primary functions of RNA molecules is to
A) transmit genetic information to offspring.
B) function in the synthesis of proteins.
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.
57) If 14C-labeled uridine triphosphate is added to the growth medium of cells, what macromolecules
will be labeled?
A) phospholipids
B) DNA
C) RNA
D) both DNA and RNA
E) proteins
58) 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
59) 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
60) 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
61) 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
62) 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) 120 adenine and 120 cytosine molecules.
E) 120 guanine and 120 thymine molecules.
