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 measures the change in free energy ($$\Delta G) $$for a chemical reaction and finds $$\Delta G = +15 kJ/$$mol. Which of the following is true about this reaction?

Accepted Answer

It is endergonic and requires an input of energy to proceed.

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

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$$^+ so $$glycolysis can continue.

Question 5

Which of the following statements about enzymes is FALSE?

Accepted Answer

Enzymes change the overall $$\Delta G of a $$reaction.

Question 6

During the light reactions of photosynthesis, what is the immediate source of electrons for Photosystem II?

Accepted Answer

Water ($$\mathrm{H_2O}$$), which is split to provide electrons, protons, and oxygen.

Question 7

Which of the following best explains why the citric acid cycle is considered a cycle?

Accepted Answer

Its starting molecule, oxaloacetate, is regenerated at the end of each turn.

Question 8

A cell is exposed to a competitive inhibitor of an enzyme. Which of the following would most likely overcome the effect of the inhibitor?

Accepted Answer

Increasing the concentration of the substrate.

Question 9

Which of the following is a correct comparison between 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 to drive ATP synthesis.

Question 10

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

Accepted Answer

To use ATP and NADPH to convert $$\mathrm{CO_2$}$$ into G3P, a carbohydrate precursor.

Question 11

A mutation causes the enzyme phosphofructokinase (PFK) to lose its ability to be inhibited by ATP. What is the most likely consequence for the cell?

Accepted Answer

The cell will continue glycolysis even when ATP levels are high, potentially wasting resources.

Question 12

Which of the following scenarios illustrates feedback inhibition in a metabolic pathway?

Accepted Answer

The final product of a pathway binds to an enzyme early in the pathway, decreasing its activity.

Question 13

Which of the following best explains why leaves appear green to the human eye?

Accepted Answer

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

Question 14

A researcher adds a noncompetitive inhibitor to an enzyme-catalyzed reaction. Which of the following best describes the effect?

Accepted Answer

The inhibitor binds away from the active site and decreases enzyme activity, regardless of substrate concentration.

Question 15

Which of the following is a correct sequence of events during linear electron flow in the light reactions of photosynthesis?

Accepted Answer

Water is split → electrons go to Photosystem II → electron transport chain → Photosystem I → NADP$$^+ is $$reduced to NADPH.

Question 16

Which of the following best explains why the majority of ATP produced during aerobic respiration comes from oxidative phosphorylation rather than glycolysis or the citric acid cycle?

Accepted Answer

Oxidative phosphorylation uses the energy from electrons carried by NADH and FADH$$_2 to $$drive ATP synthesis via a proton gradient.

Question 17

Which of the following is a key difference between aerobic respiration and fermentation?

Accepted Answer

Aerobic respiration uses an electron transport chain with oxygen as the final electron acceptor, while fermentation does not use an electron transport chain.

Question 18

A plant is exposed to light, but its thylakoid membranes are damaged so that protons cannot accumulate in the thylakoid space. What is the most immediate effect on photosynthesis?

Accepted Answer

ATP synthesis by photophosphorylation will decrease or stop.

Question 19

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

Accepted Answer

Catabolic pathways release energy by breaking down molecules, and anabolic pathways use that energy to build complex molecules.

Metabolism, Cellular Respiration, and Photosynthesis: Study Guide

Guida di studio - Domande di pratica

Study guide - Flashcard