Chapter 5 Practice Questions

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

A

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

A

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

A

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, starch, and amylopectin B) glycogen and cellulose C) cellulose and chitin D) starch and chitin E) starch, amylopectin, and cellulose

A

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.

A

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

A

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

A

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.

A

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.

A

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

A

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

B

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.

B

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 linkages 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.

B

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.

B

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.

B

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.

B

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

B

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

B

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

B

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.

B

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.

B

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

C

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.

C

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) C6H12O6 C) C60H102O51 D) C60H100O50 E) C60H111O51

C

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

C

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.

C

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

D

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

D

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

D

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.

D

Which of the following pairs of base sequences could form a short stretch of a normal double helix of DNA? A) 5ʹ-purine-pyrimidine-purine-pyrimidine-3ʹ with 3ʹ-purine-pyrimidine-purine-pyrimidine-5ʹ B) 5ʹ-A-G-C-T-3ʹ with 5ʹ-T-C-G-A-3ʹ C) 5ʹ-G-C-G-C-3ʹ with 5ʹ-T-A-T-A-3ʹ D) 5ʹ-A-T-G-C-3ʹ with 5ʹ-G-C-A-T-3ʹ E) All of these pairs are correct.

D

Which term includes all others in the list? A) monosaccharide B) disaccharide C) starch D) carbohydrate E) polysaccharide

D

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

E

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

E

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

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

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.

E