Question 1

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

Accepted Answer

To break down glucose and other molecules to produce ATP for cellular work

Question 2

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

Accepted Answer

$$2$$ ATP and $$2$$ NADH

Question 3

Which enzyme in glycolysis is responsible for the feedback inhibition by ATP, and how does this regulation occur?

Accepted Answer

Phosphofructokinase; ATP binds to a regulatory site, decreasing enzyme activity

Question 4

In the absence of oxygen, which process allows glycolysis to continue by regenerating NAD$$^+$$?

Accepted Answer

Fermentation

Question 5

Which of the following is a correct sequence of the four main stages of cellular respiration?

Accepted Answer

Glycolysis → Pyruvate processing → Citric acid cycle → Electron transport and oxidative phosphorylation

Question 6

A patient with a genetic defect in the enzyme pyruvate dehydrogenase would have difficulty performing which step of cellular respiration?

Accepted Answer

Conversion of pyruvate to acetyl CoA

Question 7

Which of the following statements about the electron transport chain (ETC) is correct?

Accepted Answer

The ETC uses the energy from electron transfers to pump protons and create a proton gradient

Question 8

Which molecule acts as the final electron acceptor in aerobic respiration, and what is the product formed?

Accepted Answer

Oxygen; water

Question 9

If a cell is exposed to a toxin that makes the inner mitochondrial membrane permeable to protons, what will be the immediate effect on ATP synthesis?

Accepted Answer

ATP synthesis will decrease because the proton gradient is dissipated

Question 10

Which of the following best explains why fats yield more ATP per gram than carbohydrates when used as an energy source?

Accepted Answer

Fats have more carbon-hydrogen bonds, which release more electrons for the electron transport chain

Question 11

Which of the following is a real-life example of metabolic reprogramming, as discussed in the context of cancer cells?

Accepted Answer

Cancer cells use alanine as an alternative energy source and can be targeted by inhibiting key enzymes in this pathway

Question 12

Which of the following best describes substrate-level phosphorylation?

Accepted Answer

ATP is produced directly by the transfer of a phosphate group from a phosphorylated substrate to ADP

Question 13

A person is exercising intensely and their muscle cells switch to lactic acid fermentation. What is the immediate benefit of this metabolic shift?

Accepted Answer

It allows glycolysis to continue by regenerating NAD$$^+$$

Question 14

Which of the following is NOT a product of the citric acid cycle per turn (one acetyl CoA)?

Accepted Answer

Glucose

Question 15

Which of the following statements about fermentation is correct?

Accepted Answer

Fermentation allows glycolysis to continue in the absence of oxygen by regenerating NAD$$^+$$

Question 16

Which of the following best explains why oxygen is the most efficient final electron acceptor in the electron transport chain?

Accepted Answer

Oxygen is highly electronegative, allowing for a large difference in potential energy and a strong proton-motive force

Question 17

Which of the following is a correct description of the fate of pyruvate in yeast cells under anaerobic conditions?

Accepted Answer

Pyruvate is converted to acetaldehyde, which is then reduced to ethanol

Question 18

Which of the following best describes the role of ATP synthase in cellular respiration?

Accepted Answer

It uses the energy from the proton gradient to phosphorylate ADP, forming ATP

Question 19

A mutation causes a cell to lack functional succinate dehydrogenase. Which process would be directly affected?

Accepted Answer

The citric acid cycle and the electron transport chain

Cellular Respiration and Fermentation: Chapter 9 Study Notes

Study Guide - Practice Questions