$\text{Glucose} + 6O_2 \rightarrow 6CO_2 + 6H_2O + 36-38ATP$

Question 1

Which of the following statements correctly describes the role of oxygen in cellular respiration?

Accepted Answer

Oxygen is the final electron acceptor in the electron transport chain, forming $H_2O$.

Question 2

During glycolysis, which molecule is directly reduced to form NADH?

Accepted Answer

NAD$^+$

Question 3

A mutation prevents the conversion of pyruvate to acetyl-CoA. Which process would be directly affected?

Accepted Answer

Krebs Cycle

Question 4

Which of the following best explains why fermentation produces less ATP than aerobic respiration?

Accepted Answer

Fermentation does not utilize the electron transport chain, so only substrate-level phosphorylation occurs.

Question 5

In the electron transport chain, what is the primary function of the energy released as electrons move through protein complexes?

Accepted Answer

To pump $H^+$ ions from the matrix into the intermembrane space, creating a chemiosmotic gradient

Question 6

Which of the following equations correctly represents the net ATP yield from one molecule of glucose during aerobic respiration?

Accepted Answer

$	ext{Glucose} + 6O_2 ightarrow 6CO_2 + 6H_2O + 36-38ATP$

Question 7

Which statement about enzymes is TRUE?

Accepted Answer

Enzymes lower the activation energy required for chemical reactions.

Question 8

A patient’s muscle cells are deprived of oxygen during intense exercise. Which metabolic pathway will be primarily used to generate ATP?

Accepted Answer

Lactic acid fermentation

Question 9

Which step in cellular respiration produces the most ATP per glucose molecule?

Accepted Answer

Electron transport chain (ETC)

Question 10

In prokaryotes, where does the electron transport chain occur?

Accepted Answer

Cell membrane

Question 11

Which molecule acts as the electron acceptor during glycolysis?

Accepted Answer

NAD$^+$

Question 12

What is the main purpose of fermentation in cells?

Accepted Answer

To regenerate NAD$^+$ so glycolysis can continue

Question 13

Which of the following is a product of alcoholic fermentation?

Accepted Answer

Ethanol and CO$_2$

Question 14

During the Krebs cycle, how many CO$_2$ molecules are released per turn?

Accepted Answer

2

Question 15

Which process directly produces ATP by substrate-level phosphorylation?

Accepted Answer

Glycolysis

Question 16

If a cell is unable to regenerate NAD$^+$, which process will be halted first?

Accepted Answer

Glycolysis

Question 17

Which of the following best describes chemiosmosis?

Accepted Answer

The flow of protons ($H^+$) through ATP synthase to generate ATP

Question 18

Which of the following is TRUE about the specificity of enzymes?

Accepted Answer

Enzymes have a specific active site that binds only particular substrates.

Question 19

A yeast cell is placed in an anaerobic environment. Which metabolic pathway will it use to generate ATP?

Accepted Answer

Alcoholic fermentation

Question 20

Which of the following correctly matches the location of each stage of cellular respiration in eukaryotic cells?

Accepted Answer

Glycolysis - cytoplasm; Krebs cycle - mitochondrial matrix; ETC - inner mitochondrial membrane

Cellular Respiration and Fermentation: Key Concepts and Processes

Study Guide - Practice Questions