Which of these molecules is not formed by dehydration reactions?
A) fatty acids
B) disaccharides
C) DNA
D) protein
E) amylose
Answer: A
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.
Answer: B
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
Answer: B
Which of the following is not a polymer?
A) glucose
B) starch
C) cellulose
D) chitin
E) DNA
Answer: A
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
Answer: C
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
Answer: C
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.
Answer: A
Which of the following polymers contain nitrogen?
A) starch
B) glycogen
C) cellulose
D) chitin
E) amylopectin
Answer: D
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
Answer: B
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
Answer: A
On food packages, to what does the term insoluble fiber refer?
A) cellulose
B) polypeptides
C) starch
D) amylopectin
E) chitin
Answer: A
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.
Answer: E
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
Answer: D
All of the following are polysaccharides except
A) lactose.
B) glycogen.
C) chitin.
D) cellulose.
E) amylopectin.
Answer: A
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.
Answer: A
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.
Answer: D
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.
Answer: C
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.
Answer: B
A molecule with the formula C₁₈H3₆O₂ is probably a
A) carbohydrate.
B) fatty acid.
C) protein.
D) nucleic acid.
E) hydrocarbon.
Answer: B
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.
Answer: A
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.
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