Question 1

Which of the following statements best explains why the hydrolysis of ATP is considered an exergonic reaction?

Accepted Answer

It releases energy because the products (ADP and Pi) have lower free energy than ATP.

Question 2

A scientist adds a competitive inhibitor to an enzyme-catalyzed reaction. Which of the following changes would most likely restore the reaction rate to its original value?

Accepted Answer

Increasing the substrate concentration.

Question 3

Which of the following best describes the role of oxygen in aerobic cellular respiration?

Accepted Answer

It acts as the final electron acceptor in the electron transport chain, forming water.

Question 4

During the light reactions of photosynthesis, what is the primary function of the linear electron flow from water to NADP⁺?

Accepted Answer

To generate ATP and NADPH for the Calvin cycle.

Question 5

Which equation correctly represents the change in free energy for a chemical reaction?

Accepted Answer

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

Question 6

A patient’s muscle cells are deprived of oxygen during intense exercise. Which process allows ATP production to continue under these conditions?

Accepted Answer

Lactic acid fermentation, which regenerates NAD⁺ for glycolysis.

Question 7

Which of the following statements about the citric acid cycle is correct?

Accepted Answer

It generates most of its ATP through substrate-level phosphorylation and produces NADH and FADH₂.

Question 8

Which of the following best explains why feedback inhibition is important in metabolic pathways?

Accepted Answer

It prevents the cell from wasting energy and resources by overproducing end products.

Question 9

Which of the following statements correctly compares substrate-level phosphorylation and oxidative phosphorylation?

Accepted Answer

Substrate-level phosphorylation transfers a phosphate group directly from a substrate to ADP, while oxidative phosphorylation uses a proton gradient and ATP synthase.

Question 10

A mutation causes an enzyme’s active site to change shape so that it no longer binds its substrate efficiently. Which property of enzymes is most directly affected?

Accepted Answer

Enzyme specificity.

Question 11

Which of the following best describes the main function of the Calvin cycle in photosynthesis?

Accepted Answer

To use ATP and NADPH to convert CO₂ into G3P, a carbohydrate precursor.

Question 12

Which of the following is a correct comparison between catabolic and anabolic pathways?

Accepted Answer

Catabolic pathways break down molecules and release energy; anabolic pathways build molecules and require energy.

Question 13

Which of the following statements about chemiosmosis is correct?

Accepted Answer

It uses the energy of a proton gradient to drive ATP synthesis via ATP synthase.

Question 14

A researcher observes that when a certain metabolic pathway’s end product accumulates, the pathway slows down. Which regulatory mechanism is most likely responsible?

Accepted Answer

Feedback inhibition.

Question 15

Which of the following best explains why leaves appear green to our eyes?

Accepted Answer

Chlorophyll absorbs violet-blue and red light, but reflects and transmits green light.

Question 16

Which process is responsible for the majority of ATP produced during aerobic respiration?

Accepted Answer

Oxidative phosphorylation.

Question 17

Which of the following is true regarding the flow of electrons during the light reactions of photosynthesis?

Accepted Answer

Electrons flow from water to NADP⁺, forming NADPH.

Question 18

Which of the following best describes the difference between NADH and NADPH?

Accepted Answer

NADH is primarily used in cellular respiration, while NADPH is used in photosynthesis.

Question 19

A cell is exposed to a noncompetitive inhibitor that binds to an enzyme. What is the most likely effect on the enzyme’s activity?

Accepted Answer

The enzyme’s activity decreases because the inhibitor changes the enzyme’s shape, making the active site less effective.

Question 20

Which of the following is a correct statement about the relationship between photosynthesis and cellular respiration?

Accepted Answer

Photosynthesis stores energy in organic molecules, while cellular respiration releases energy from organic molecules.

Metabolism, Cellular Respiration, and Photosynthesis: Study Guide

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