$$C_6H_{12}O_6$ + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{ATP}$$

Question 1

Which of the following best describes the main purpose of cellular respiration in eukaryotic cells?

Accepted Answer

To transfer energy from food molecules into ATP

Question 2

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

Accepted Answer

Oxygen ($$O_2)$$

Question 3

Which of the following equations correctly represents the overall process of aerobic cellular respiration?

Accepted Answer

$$C_6H_{12}O_6$ + 6O_2 ightarrow 6CO_2 + 6H_2O + 	ext{ATP}$$

Question 4

Which stage of cellular respiration produces the majority of ATP?

Accepted Answer

Oxidative phosphorylation

Question 5

What is the main function of NAD⁺ and FAD in cellular respiration?

Accepted Answer

To serve as electron carriers, transporting high-energy electrons to the electron transport chain

Question 6

Which process occurs in the cytosol of eukaryotic cells and results in the production of pyruvate?

Accepted Answer

Glycolysis

Question 7

During glycolysis, what is the net gain of ATP and NADH per molecule of glucose?

Accepted Answer

2 ATP and 2 NADH

Question 8

Which of the following best explains why cells harvest energy from food in small, controlled steps rather than all at once?

Accepted Answer

To prevent the loss of most energy as heat or light

Question 9

What is the main difference between substrate-level phosphorylation and oxidative phosphorylation?

Accepted Answer

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

Question 10

Which of the following is a product of pyruvate oxidation per molecule of pyruvate?

Accepted Answer

1 NADH, 1 CO₂, 1 acetyl CoA

Question 11

In the citric acid cycle, what is the total yield of NADH, FADH₂, ATP, and CO₂ per glucose molecule?

Accepted Answer

6 NADH, 2 FADH₂, 2 ATP, 4 CO₂

Question 12

What is the role of the electron transport chain in oxidative phosphorylation?

Accepted Answer

To transfer electrons from NADH and FADH₂ to oxygen, pumping protons to create a gradient

Question 13

Why is the inner mitochondrial membrane highly folded into cristae?

Accepted Answer

To provide a large surface area for the electron transport chain and ATP synthase

Question 14

Which process allows glycolysis to continue in the absence of oxygen by regenerating NAD⁺?

Accepted Answer

Fermentation

Question 15

In lactic acid fermentation, what is the fate of pyruvate?

Accepted Answer

It is directly reduced by NADH to form lactate

Question 16

Which of the following statements about fermentation, anaerobic respiration, and aerobic respiration is correct?

Accepted Answer

Anaerobic respiration uses a non-oxygen final electron acceptor

Question 17

A muscle cell is working hard and oxygen becomes limited. Which pathway will the cell use to continue producing ATP?

Accepted Answer

Lactic acid fermentation

Question 18

Which of the following best describes chemiosmosis in cellular respiration?

Accepted Answer

The use of a proton gradient to drive ATP synthesis via ATP synthase

Question 19

If a poison blocks the function of ATP synthase, which of the following would be directly affected?

Accepted Answer

The synthesis of ATP during oxidative phosphorylation

Question 20

Which of the following is a correct description of a redox reaction in cellular respiration?

Accepted Answer

Glucose is oxidized and oxygen is reduced

Cellular Respiration and Fermentation: Energy Harvesting in Cells

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