Chapter 6 Metabolism: Energy and Enzymes

1. Which of the following best describes the difference between kinetic and potential energy?

   A. Kinetic energy is stored; potential energy is energy in motion.

   B. Kinetic energy is energy in motion; potential energy is stored energy.

   C. Both are forms of stored energy.

   D. Both are forms of energy in motion

Kinetic energy is energy in motion; potential energy is stored energy.

2. According to the first law of thermodynamics:

   A. Energy can be created but not destroyed.

   B. Energy can be destroyed but not created

   C. Energy cannot be created or destroyed

   D. Energy is always lost as heat

C. Energy cannot be created or destroyed

The second law of thermodynamics states that:

A. Energy transformations are 100% efficient

B. Entropy (disorder) of the universe tends to increase.

C. Heat cannot flow from hot to cold objects

D. Energy cannot be transformed from one form to another.

B. Entropy (disorder) of the universe tends to increase.

4. Free energy is best defined as:

a) Energy that costs nothing to produce

b) Energy available to do work in a system

c) Energy that moves freely through space

d) Energy stored in chemical bonds

b) Energy available to do work in a system

5. Which type of reaction releases energy to the surroundings?

a) Endothermic

b) Exothermic

c) Anabolic

d) Reduction

b) Exothermic

6. Catabolic pathways:

a) Build complex molecules from simple ones

b) Break down complex molecules into simpler ones

c) Require energy input

d) Only occur during photosynthesis

b) Break down complex molecules into simpler ones

7. Anabolic pathways:

a) Break down complex molecules

b) Release energy

c) Build complex molecules from simpler ones

d) Do not require enzymes

c) Build complex molecules from simpler ones

8. In a coupled reaction:

a) Two reactions occur simultaneously but independently

b) An exergonic reaction drives an endergonic reaction

c) Only catabolic reactions can participate

d) No net energy change occurs

b) An exergonic reaction drives an endergonic reaction

9. ADP is generated when:

a) ATP gains a phosphate group

b) ATP loses a phosphate group '

c) Glucose is broken down

d) Proteins are synthesized

b) ATP loses a phosphate group

10. ATP is considered the "energy currency" of the cell because:

a) It stores large amounts of energy permanently

b) It can be easily broken down to release energy and reformed

c) It is the most abundant molecule in cells

d) It cannot be recycled

b) It can be easily broken down to release energy and reformed

11. Enzymes function by:

a) Providing energy for reactions

b) Lowering the activation energy of reactions

c) Changing the equilibrium of reactions

d) Increasing the temperature of reactions

b) Lowering the activation energy of reactions

11. Enzymes function by:

a) Providing energy for reactions

b) Lowering the activation energy of reactions

c) Changing the equilibrium of reactions

d) Increasing the temperature of reactions

d) Increasing the temperature of reactions

12. Which environmental factor does NOT typically affect enzyme function?

a) Temperature

b) pH

c) Substrate concentration

d) The color of the solution

d) The color of the solution

13. In the induced fit model of enzyme action:

a) The enzyme shape never changes

b) The substrate changes shape to fit the enzyme

c) The enzyme changes shape slightly to better accommodate the substrate

d) Both enzyme and substrate are destroyed in the process

c) The enzyme changes shape slightly to better accommodate the substrate

14. During the enzyme catalytic cycle, the correct order of events is:

a) Product release → Substrate binding → Catalysis → Product formation

b) Substrate binding → Product formation → Catalysis → Product release

c) Substrate binding → Catalysis → Product formation → Product release

d) Catalysis → Substrate binding → Product formation → Product release

c) Substrate binding → Catalysis → Product formation → Product release

15. In redox reactions:

a) Reduction involves the loss of electrons; oxidation involves the gain of electrons b) Oxidation involves the loss of electrons; reduction involves the gain of electrons c) Both processes involve only the transfer of protons

d) No electron transfer occurs

b) Oxidation involves the loss of electrons; reduction involves the gain of electrons

16. Which statement best describes the difference between endothermic and exothermic reactions?

a) Endothermic reactions release heat; exothermic reactions absorb heat

b) Endothermic reactions absorb heat; exothermic reactions release heat

c) Both types of reactions release heat

d) Both types of reactions absorb heat

b) Endothermic reactions absorb heat; exothermic reactions release heat

17. The ATP cycle involves:

a) Only the breakdown of ATP to ADP

b) Only the synthesis of ATP from ADP

c) The continuous breakdown and regeneration of ATP

d) The permanent storage of energy in ATP

c) The continuous breakdown and regeneration of ATP

18. Which statement about redox reactions in photosynthesis is correct?

a) Water is oxidized and CO₂ is reduced

b) Water is reduced and CO₂ is oxidized

c) Both water and CO₂ are oxidized

d) Both water and CO₂ are reduced

a) Water is oxidized and CO₂ is reduced

19. In cellular respiration, glucose is:

a) Oxidized to release energy

b) Reduced to release energy

c) Neither oxidized nor reduced

d) Used only for structural purposes

a) Oxidized to release energy

20. Which factor would most likely denature an enzyme?

a) Optimal pH conditions

b) Moderate temperature increase

c) Extreme heat

d) Appropriate substrate concentration

c) Extreme heat