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Chemical Foundations
2
PART A: Linking Concepts and Facts
2.1 Covalent Bonds and Noncovalent Interactions
1. Covalent bonds between which of the following pairs of atoms are nonpolar?
a. C–C
b. C–H
c. O–H
d. a and b
Ans: d
2. Which of the following is a noncovalent interaction?
a. hydrophobic effect
b. ionic interactions
c. Van der Waals interactions
d. all of the above
Ans: e
3. Which of the following is the strongest interaction?
a. hydrogen bond
b. ionic bond
c. phosphoanhydride bond
d. Van der Waals interaction
Ans: d
4. Which of the following is the weakest interaction?
a. hydrogen bond
b. ionic bond
c. phosphoanhydride bond
d. Van der Waals interaction
Ans: d
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5. When two atoms differing in electronegativity are joined in a covalent bond, then the
a. electrons are shared equally between the atoms.
b. bond is nonpolar.
c. resulting compound is devoid of any dipole moment.
d. atom with the greater electronegativity attracts the bonded electrons more.
Ans: d
2.2 Chemical Building Blocks of Cells
6. Which of the following is a negatively charged amino acid?
a. alanine
b. aspartate
c. glutamine
d. histidine
Ans: b
7. Which of the following is a hydrophilic amino acid?
a. aspartate
b. serine
c. tryptophan
d. a and b
Ans: d
8. Adenosine is a
a. component of RNA.
b nucleotide.
c. pyrimidine.
d. a and b
Ans: a
9. Which of the following is a monosaccharide?
a. fructose
b. galactose
c. glucose
d. all of the above
Ans: d
10. Which of the following is composed of a bilayer?
a. cell membrane
b. liposome
c. micelle
d a and b
Ans: d
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2.3 Chemical Equilibrium
11. A 1-mL solution of 0.05 M H2SO4 is diluted to 100 mL at 25°C. What is the pH of the resulting solution?
a. 1
b. 2
c. 3
d. 4
Ans: c
12. A 1-mL solution of 0.1 M NaOH is diluted to 1 L at 25°C. What is the pH of the resulting solution?
a. 1
b. 7
c. 10
d. 13
Ans: c
13. The pK a of the weak base NH3 is 9.25. When present in lysosomes, a subcellular organelle—ammonia—is almost
totally protonated. Which of the pH values listed below is most likely to be that of the lysosome lumen?
a. 1
b. 5
c. 8
d. 14
Ans: b
14. If the equilibrium constant for the reaction A → B is 0.5 and the initial concentration of A is 25 mM and of B is
12.5 mM, then the reaction
a. will proceed in the direction it is written, producing a net increase in the concentration of B.
b. will produce energy, which can be used to drive ATP synthesis.
c. will proceed in the reverse direction, producing a net increase in the concentration of A.
d. is at equilibrium.
Ans: d
15. For the binding reaction A + B → AB, the dissociation constant is equal to
a. [ΑΒ]/([Α] + [Β]).
b. ([A] + [B])/[AB].
c. K eq
d. a and c
Ans: b
2.4 Biochemical Energetics
16. In a biochemical reaction in which ∆H < 0 and ∆S > 0,
a. the reaction is spontaneous.
b. the reaction is endothermic.
c. the reaction is endergonic.
d. ∆G is positive.
Ans: a
17. In the reaction NAD+ + H+ + 2e− → NADH, NAD+ becomes
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a. dehydrated.
b. hydrolyzed.
c. oxidized.
d. reduced.
Ans: d
18. The ultimate source of chemical energy for all cells is
a. electricity.
b. heat.
c. light.
d. magnetism.
Ans: c
19. Hydrolysis of ATP
a. is endothermic.
b. has a positive ∆G value.
c. must be coupled to an energetically favorable reaction.
d. none of the above
Ans: e
20. What is [P]/[R] when ∆G = ∆G°´?
a. –1
b. 0
c. 1
d. 2.3
Ans: c
21. A reaction with a positive ∆G value can be made energetically favorable by increasing the
a. ∆G°′.
b. starting concentration of products.
c. starting concentration of reactants.
d. a or b
Ans: c
22. Photosynthesis by plants and certain microbes traps the energy in light and uses it to
a. reduce glucose into carbon dioxide.
b. synthesize ATP from ADP and inorganic phosphate.
c. generate ATP from the oxidation of reduced inorganic compounds.
d. none of the above
Ans: b
23. NAD+ and FAD are often referred to as
a. redox proteins.
b. polymers.
c. reduced dinucleotides.
d. electron-carrying coenzymes.
Ans: d
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Chemical Foundations
2
PART A: Linking Concepts and Facts
2.1 Covalent Bonds and Noncovalent Interactions
1. Covalent bonds between which of the following pairs of atoms are nonpolar?
a. C–C
b. C–H
c. O–H
d. a and b
Ans: d
2. Which of the following is a noncovalent interaction?
a. hydrophobic effect
b. ionic interactions
c. Van der Waals interactions
d. all of the above
Ans: e
3. Which of the following is the strongest interaction?
a. hydrogen bond
b. ionic bond
c. phosphoanhydride bond
d. Van der Waals interaction
Ans: d
4. Which of the following is the weakest interaction?
a. hydrogen bond
b. ionic bond
c. phosphoanhydride bond
d. Van der Waals interaction
Ans: d
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5. When two atoms differing in electronegativity are joined in a covalent bond, then the
a. electrons are shared equally between the atoms.
b. bond is nonpolar.
c. resulting compound is devoid of any dipole moment.
d. atom with the greater electronegativity attracts the bonded electrons more.
Ans: d
2.2 Chemical Building Blocks of Cells
6. Which of the following is a negatively charged amino acid?
a. alanine
b. aspartate
c. glutamine
d. histidine
Ans: b
7. Which of the following is a hydrophilic amino acid?
a. aspartate
b. serine
c. tryptophan
d. a and b
Ans: d
8. Adenosine is a
a. component of RNA.
b nucleotide.
c. pyrimidine.
d. a and b
Ans: a
9. Which of the following is a monosaccharide?
a. fructose
b. galactose
c. glucose
d. all of the above
Ans: d
10. Which of the following is composed of a bilayer?
a. cell membrane
b. liposome
c. micelle
d a and b
Ans: d
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2.3 Chemical Equilibrium
11. A 1-mL solution of 0.05 M H2SO4 is diluted to 100 mL at 25°C. What is the pH of the resulting solution?
a. 1
b. 2
c. 3
d. 4
Ans: c
12. A 1-mL solution of 0.1 M NaOH is diluted to 1 L at 25°C. What is the pH of the resulting solution?
a. 1
b. 7
c. 10
d. 13
Ans: c
13. The pK a of the weak base NH3 is 9.25. When present in lysosomes, a subcellular organelle—ammonia—is almost
totally protonated. Which of the pH values listed below is most likely to be that of the lysosome lumen?
a. 1
b. 5
c. 8
d. 14
Ans: b
14. If the equilibrium constant for the reaction A → B is 0.5 and the initial concentration of A is 25 mM and of B is
12.5 mM, then the reaction
a. will proceed in the direction it is written, producing a net increase in the concentration of B.
b. will produce energy, which can be used to drive ATP synthesis.
c. will proceed in the reverse direction, producing a net increase in the concentration of A.
d. is at equilibrium.
Ans: d
15. For the binding reaction A + B → AB, the dissociation constant is equal to
a. [ΑΒ]/([Α] + [Β]).
b. ([A] + [B])/[AB].
c. K eq
d. a and c
Ans: b
2.4 Biochemical Energetics
16. In a biochemical reaction in which ∆H < 0 and ∆S > 0,
a. the reaction is spontaneous.
b. the reaction is endothermic.
c. the reaction is endergonic.
d. ∆G is positive.
Ans: a
17. In the reaction NAD+ + H+ + 2e− → NADH, NAD+ becomes
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N
a. dehydrated.
b. hydrolyzed.
c. oxidized.
d. reduced.
Ans: d
18. The ultimate source of chemical energy for all cells is
a. electricity.
b. heat.
c. light.
d. magnetism.
Ans: c
19. Hydrolysis of ATP
a. is endothermic.
b. has a positive ∆G value.
c. must be coupled to an energetically favorable reaction.
d. none of the above
Ans: e
20. What is [P]/[R] when ∆G = ∆G°´?
a. –1
b. 0
c. 1
d. 2.3
Ans: c
21. A reaction with a positive ∆G value can be made energetically favorable by increasing the
a. ∆G°′.
b. starting concentration of products.
c. starting concentration of reactants.
d. a or b
Ans: c
22. Photosynthesis by plants and certain microbes traps the energy in light and uses it to
a. reduce glucose into carbon dioxide.
b. synthesize ATP from ADP and inorganic phosphate.
c. generate ATP from the oxidation of reduced inorganic compounds.
d. none of the above
Ans: b
23. NAD+ and FAD are often referred to as
a. redox proteins.
b. polymers.
c. reduced dinucleotides.
d. electron-carrying coenzymes.
Ans: d
