Question 1

Which of the following statements correctly distinguishes between facilitated diffusion and active transport across a cell membrane?

Accepted Answer

Facilitated diffusion depends on an existing energy gradient acting on the transported substance, while active transport makes such a gradient.

Question 2

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

Accepted Answer

Anabolic pathways consume energy to build complex molecules, while catabolic pathways release energy by breaking down complex molecules.

Question 3

A diver climbs up a platform, converting chemical energy from food into muscle movement. At the top, the diver has increased:

Accepted Answer

Potential energy

Question 4

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

Accepted Answer

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

Question 5

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

Accepted Answer

$$\Delta G = \Delta H - T\Delta S$$

Question 6

A reaction has a $$\Delta G of$$ $$-5.6$$ kcal/mol. Which of the following statements is most likely true?

Accepted Answer

The reaction would proceed by itself but might be very slow.

Question 7

Which of the following best explains why living organisms can create highly ordered structures without violating the second law of thermodynamics?

Accepted Answer

Living organisms create order locally, but the energy transformations generate waste heat that increases the entropy of the universe.

Question 8

Which of the following is an example of energy coupling in cells?

Accepted Answer

Using the energy released from ATP hydrolysis to drive the active transport of ions across a membrane.

Question 9

What is the primary function of enzymes in biological systems?

Accepted Answer

To lower the activation energy barrier of specific reactions.

Question 10

Which of the following statements about enzyme inhibition is correct?

Accepted Answer

Competitive inhibitors resemble the substrate and bind to the active site.

Question 11

A metabolic pathway consists of several steps, each catalyzed by a specific enzyme. What would most likely happen if the end product of the pathway accumulates in excess?

Accepted Answer

The end product would act as a feedback inhibitor, shutting down the pathway.

Question 12

Which of the following best describes the effect of temperature on enzyme activity?

Accepted Answer

Each enzyme has an optimal temperature at which its activity is maximal; above this temperature, activity decreases.

Question 13

Which of the following is true regarding the regeneration of ATP in cells?

Accepted Answer

ATP is regenerated by the addition of a phosphate group to ADP, using energy from catabolic reactions.

Question 14

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

Accepted Answer

Exergonic reactions release free energy and have a negative $$\Delta G.$$

Question 15

Which of the following best explains why the oxidation of glucose to CO$$_2$$ and H$$_2O is $$very slow at room temperature, despite being highly exergonic?

Accepted Answer

Few glucose and oxygen molecules have the activation energy at room temperature.

Question 16

Which of the following is an example of allosteric regulation of an enzyme?

Accepted Answer

A regulatory molecule binds to a site other than the active site, changing the enzyme's shape and activity.

Question 17

Which of the following statements about the ATP cycle is correct?

Accepted Answer

The ATP cycle couples energy-yielding processes to energy-consuming ones.

Question 18

Which of the following is true about the effect of pH on enzyme activity in the human digestive system?

Accepted Answer

Pepsin, a stomach enzyme, has an optimal pH of about 2, while trypsin, an intestinal enzyme, has an optimal pH of about 8.

Question 19

Which of the following best describes the role of cofactors in enzyme activity?

Accepted Answer

Cofactors are nonprotein helpers that are required for some enzymes to function.

Energy, Metabolism, and Enzymes: Study Notes for General Biology

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