60 Review Questions

4. Energy is stored long-term in the bonds of _____ and used short-term to perform work from a(n) _____ molecule.

1. ATP : glucose
2. an anabolic molecule : catabolic molecule
3. glucose : ATP
4. a catabolic molecule : anabolic molecule

5. DNA replication involves unwinding two strands of parent DNA, copying each strand to synthesize complementary strands, and releasing the parent and daughter DNA. Which of the following accurately describes this process?

1. This is an anabolic process.
2. This is a catabolic process.
3. This is both anabolic and catabolic.
4. This is a metabolic process but is neither anabolic nor catabolic.

6. Consider a pendulum swinging. Which type(s) of energy is/are associated with the pendulum in the following instances: i. the moment at which it completes one cycle, just before it begins to fall back towards the other end, ii. the moment that it is in the middle between the two ends, and iii. just before it reaches the end of one cycle (just before instant i.).

1. i. potential and kinetic, ii. potential and kinetic, iii. kinetic
2. i. potential, ii. potential and kinetic, iii. potential and kinetic
3. i. potential, ii. kinetic, iii. potential and kinetic
4. i. potential and kinetic, ii. kinetic iii. kinetic

7. Which of the following comparisons or contrasts between endergonic and exergonic reactions is false?

1. Endergonic reactions have a positive ∆G and exergonic reactions have a negative ∆G.
2. Endergonic reactions consume energy and exergonic reactions release energy.
3. Both endergonic and exergonic reactions require a small amount of energy to overcome an activation barrier.
4. Endergonic reactions take place slowly and exergonic reactions take place quickly.

8. Which of the following is the best way to judge the relative activation energies between two given chemical reactions?

1. Compare the ∆G values between the two reactions.
2. Compare their reaction rates.
3. Compare their ideal environmental conditions.
4. Compare the spontaneity between the two reactions.

9. Which of the following is not an example of an energy transformation?

1. turning on a light switch
2. solar panels at work
3. formation of static electricity
4. none of the above

10. In each of the three systems, determine the state of entropy (low or high) when comparing the first and second: i. the instant that a perfume bottle is sprayed compared with 30 seconds later, ii. an old 1950s car compared with a brand new car, and iii. a living cell compared with a dead cell.

1. i. low, ii. high, iii. low
2. i. low, ii. high, iii. high
3. i. high, ii. low, iii. high
4. i. high, ii. low, iii. low

11. The energy released by the hydrolysis of ATP is____

1. primarily stored between the alpha and beta phosphates
2. equal to −57 kcal/mol
3. harnessed as heat energy by the cell to perform work
4. providing energy to coupled reactions

12. Which of the following molecules is likely to have the most potential energy?

1. sucrose
2. ATP
3. glucose
4. ADP

13. Which of the following is not true about enzymes:

1. They increase ∆G of reactions.
2. They are usually made of amino acids.
3. They lower the activation energy of chemical reactions.
4. Each one is specific to the particular substrate(s) to which it binds.

14. An allosteric inhibitor does which of the following?

1. Binds to an enzyme away from the active site and changes the conformation of the active site, increasing its affinity for substrate binding.
2. Binds to the active site and blocks it from binding substrate.
3. Binds to an enzyme away from the active site and changes the conformation of the active site, decreasing its affinity for the substrate.
4. Binds directly to the active site and mimics the substrate.

15. Which of the following analogies best describes the induced-fit model of enzyme-substrate binding?

1. a hug between two people
2. a key fitting into a lock
3. a square peg fitting through the square hole and a round peg fitting through the round hole of a children’s toy
4. the fitting together of two jigsaw puzzle pieces