Download Thermodynamics and enzymes

ENERGY AND METABOLISM
1
Thermodynamics and Enzymes
Questions 1 - 7 refer to the following diagram.
1. Which arrow represents the energy of activation?
a. A
b. B
c. C
d. D
2. Which arrow represents the amount of net free energy released by this reaction?
a. A
b. B
c. C
d. D
3. Which arrow would be the same irrespective of whether the reaction was not catalyzed or
catalyzed by an enzyme?
a. A
b. B
c. C
d. D
4. The reaction is
a. exergonic
b. endergonic
c. pleogonic
d. allosteric
5. The reaction would have
a. a positive ∆G b. a negative ∆G
c. could be either positive of negative depending on the temperature
d. would be positive without an enzyme but negative with an enzyme
6. The reaction would have an equilibrium constant
a. greater than one
b. less than 1 c. equal to one
d. that would vary depending on whether or not an enzyme were present
7. If the proper enzyme was added to this reaction, we would expect the lowest free energy to be
attained in a shorter time period. (T/F)
8. During oxidation/reduction reaction, the oxidized molecule
a. is losing hydrogens
b. is losing electrons
c. is gaining hydrogens d. is gaining electrons
ENERGY AND METABOLISM
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9. Endothermic reactions require input of energy to proceed. (T/F)
10.
Which of the following is NOT true of reactions which proceed spontaneously?
a. The have a + ∆G.
b. they have a Keq > 1
c. they release energy
11. Which of the following DOES NOT follow from the 2nd Law of Thermodynamics?
a. the free energy of a system is always declining
b. entropy is always decreasing
c. organized system spontaneously become less organized
d. solutes diffuse from a region of high concentration to regions of lower concentration
12. In a given reaction, the amount of product produced is 5 times the amount of reactant that
remains. This reaction would have
a. a Keq > 1.
b. a Keq < 1.
c. a Keq = 1.
d. a Keq = 0.
13. Allosteric modulators may either increase or decrease the rate of enzyme activity depending
on which modulator and enzyme are involved. (T/F)
14. The binding of carbon monoxide to the heme group of hemoglobin is a classic example of an
allosteric effect. (T/F)
15. Enzyme cofactors are things like Mg ions which become permanently attached to the
enzymes and thus speed up their operation. (T/F)
16. Enzymes
a. increase ∆G.
b. increase Keq
c. increase the reaction rate
d. all of the above
Definitions. Write clear, concise definitions of no more than one sentence.
1. Denaturation
2. Free energy
3. Activation energy