Question 1

Which of the following best explains why the hydrolysis of ATP is often coupled to endergonic reactions in cells?

Accepted Answer

It provides energy by breaking ATP into ADP and Pi, which can drive reactions with positive $$\Delta G.$$

Question 2

During cellular respiration, which molecule acts as the final electron acceptor in the electron transport chain?

Accepted Answer

Oxygen ($$O_2)$$

Question 3

In the citric acid cycle, how many carbon atoms are released as $$CO_2$$ for each acetyl CoA that enters the cycle?

Accepted Answer

Two

Question 4

Which of the following statements about oxidative phosphorylation is correct?

Accepted Answer

It uses the energy from a proton gradient to synthesize ATP via ATP synthase.

Question 5

What would happen to the rate of glycolysis in a muscle cell if the concentration of AMP increased significantly?

Accepted Answer

Glycolysis would speed up because AMP activates phosphofructokinase.

Question 6

Which experiment provided evidence that oxygen released during photosynthesis comes from water and not carbon dioxide?

Accepted Answer

Using heavy isotope $$^{18}O in$$ $$H_2O$$ and observing $$O_2$$ release.

Question 7

Which of the following is a product of lactic acid fermentation in muscle cells?

Accepted Answer

Lactate

Question 8

What is the main function of Rubisco in photosynthesis?

Accepted Answer

To fix carbon dioxide into organic molecules during the Calvin cycle.

Question 9

Which of the following best describes the role of NAD+/NADH in cellular respiration?

Accepted Answer

NADH carries electrons to the electron transport chain for ATP production.

Question 10

Which of the following processes occurs in the mitochondrial matrix?

Accepted Answer

Citric acid cycle (Krebs cycle)

Question 11

A cell is exposed to cyanide, which inhibits cytochrome c oxidase in the electron transport chain. What is the most immediate effect?

Accepted Answer

Electron flow through the electron transport chain stops, halting ATP production by oxidative phosphorylation.

Question 12

Which of the following is true about entropy ($$S) in $$biological systems?

Accepted Answer

Cells maintain order locally by increasing entropy in their surroundings.

Question 13

Which molecule is regenerated at the end of the Calvin cycle, allowing the cycle to continue?

Accepted Answer

RuBP (ribulose bisphosphate)

Question 14

Which of the following statements about the light reactions of photosynthesis is correct?

Accepted Answer

They generate ATP and NADPH, which are used in the Calvin cycle.

Question 15

What is the primary function of the electron transport chain in mitochondria?

Accepted Answer

To create a proton gradient that drives ATP synthesis via chemiosmosis.

Question 16

Which of the following is a correct description of substrate-level phosphorylation?

Accepted Answer

ATP is produced directly by transferring a phosphate group from a substrate to ADP.

Question 17

Which of the following best describes the role of the enzyme ATP synthase?

Accepted Answer

It synthesizes ATP from ADP and Pi using the energy of a proton gradient.

Question 18

In photosynthesis, what is the main purpose of splitting water molecules during the light reactions?

Accepted Answer

To provide electrons to replace those lost by chlorophyll in photosystem II.

Question 19

Which of the following is a direct product of glycolysis?

Accepted Answer

Pyruvate

Question 20

Which of the following best explains why cells use fermentation under anaerobic conditions?

Accepted Answer

To regenerate NAD+ so glycolysis can continue in the absence of oxygen.

Cellular Respiration and Photosynthesis: Key Concepts and Processes

Study Guide - Practice Questions