Question 1

Which of the following best describes the difference between catabolic and anabolic pathways in metabolism?

Accepted Answer

Catabolic pathways release energy by breaking down complex molecules, while anabolic pathways consume energy to build complex molecules.

Question 2

According to the first law of thermodynamics, which of the following statements is correct?

Accepted Answer

Energy can be transferred and transformed, but it cannot be created or destroyed.

Question 3

A car engine converts the chemical energy in gasoline into kinetic energy and heat. Which law of thermodynamics does this illustrate, and why?

Accepted Answer

First law, because energy is transformed from one form to another but not destroyed.

Question 4

Which of the following best explains why living organisms do not violate the second law of thermodynamics?

Accepted Answer

Organisms increase the entropy of their surroundings, so the total entropy of the system and surroundings increases.

Question 5

Which of the following equations correctly represents the change in free energy ($$\Delta G) $$for a chemical reaction?

Accepted Answer

$$\Delta G = G_{final} - G_{initial}$$

Question 6

Which of the following statements about exergonic and endergonic reactions is correct?

Accepted Answer

Exergonic reactions release energy and have $$\Delta G \u003c 0.$$

Question 7

In the ATP cycle, which molecule has higher free energy?

Accepted Answer

ATP

Question 8

Which of the following best describes the role of enzymes in biological reactions?

Accepted Answer

Enzymes lower the activation energy ($$E_A) $$required for a reaction to proceed.

Question 9

Which of the following is NOT a way that the active site of an enzyme can lower activation energy?

Accepted Answer

Increasing the temperature of the reaction

Question 10

A competitive inhibitor decreases the rate of an enzyme-catalyzed reaction by:

Accepted Answer

Binding to the active site and blocking substrate binding

Question 11

Which of the following best describes feedback inhibition in a metabolic pathway?

Accepted Answer

The end product of the pathway inhibits an enzyme involved early in the pathway.

Question 12

Which of the following is an example of an allosteric activator?

Accepted Answer

A molecule that binds to a regulatory site and stabilizes the enzyme's active form

Question 13

Which of the following statements about cooperativity is correct?

Accepted Answer

Cooperativity occurs when binding of a substrate to one active site stabilizes favorable conformational changes at all other subunits.

Question 14

Which of the following best describes the difference between an open and a closed system in thermodynamics?

Accepted Answer

An open system can exchange both energy and matter with its surroundings.

Question 15

Which of the following is a correct statement about the relationship between free energy and stability?

Accepted Answer

A system with lower free energy is more stable.

Question 16

Which of the following is true about the effect of temperature and pH on enzyme activity?

Accepted Answer

Each enzyme has a specific optimal temperature and pH at which it functions best.

Question 17

Which of the following is an example of a cofactor?

Accepted Answer

A metal ion such as $$Zn^{2+}$$

Question 18

Which of the following best describes energy coupling in cells?

Accepted Answer

Energy coupling is the use of an exergonic process to drive an endergonic one.

Question 19

Which of the following statements about metabolic equilibrium is correct?

Accepted Answer

Metabolic equilibrium means no work can be done.

Energy, Metabolism, and Enzyme Function in Cells

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