$$\mathrm{C_6H_{12}O_6$} + 6\ \mathrm{O_2$} \rightarrow 6\ \mathrm{CO_2$} + 6\ \mathrm{H_2O} + \text{energy (ATP)}$$

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 is responsible for the regulation of glycolysis through feedback inhibition by ATP?

Accepted Answer

Phosphofructokinase

Question 4

What is the fate of pyruvate in eukaryotic cells under aerobic conditions?

Accepted Answer

It is transported into the mitochondria and converted to acetyl CoA

Question 5

Which of the following statements about the citric acid cycle is correct?

Accepted Answer

It oxidizes acetyl CoA to produce CO$$_2$$, NADH, FADH$$_2$$, and ATP

Question 6

What is the primary role of the electron transport chain (ETC) in cellular respiration?

Accepted Answer

To transfer electrons from NADH and FADH$$_2 to $$oxygen, creating a proton gradient

Question 7

Which molecule acts as the final electron acceptor in aerobic respiration?

Accepted Answer

Oxygen ($$O_2)$$

Question 8

How does ATP synthase produce ATP during oxidative phosphorylation?

Accepted Answer

By using the energy from a proton gradient to phosphorylate ADP

Question 9

Which of the following best explains why fermentation is less efficient than aerobic respiration?

Accepted Answer

Fermentation does not use an electron transport chain, so less ATP is produced per glucose

Question 10

A patient has a genetic defect that prevents the phosphorylation of pyruvate dehydrogenase. What is the most likely consequence?

Accepted Answer

Pyruvate dehydrogenase will be constantly active, leading to excessive acetyl CoA production

Question 11

Which of the following is a correct summary equation for aerobic cellular respiration?

Accepted Answer

$$\mathrm{C_6H_{12}O_6$} + 6\ \mathrm{O_2$} ightarrow 6\ \mathrm{CO_2$} + 6\ \mathrm{H_2O} + 	ext{energy (ATP)}$$

Question 12

Which of the following best describes the role of feedback inhibition in glycolysis?

Accepted Answer

It slows down glycolysis when ATP is abundant by inhibiting phosphofructokinase

Question 13

In the absence of oxygen, what is the primary function of fermentation in muscle cells?

Accepted Answer

To regenerate NAD$$^+ so $$glycolysis can continue

Question 14

Which of the following molecules can enter cellular respiration at the level of glycolysis?

Accepted Answer

Glycerol

Question 15

A cell is exposed to a toxin that blocks the function of ubiquinone (Q) in the electron transport chain. What is the most immediate effect?

Accepted Answer

Electron flow through the ETC will stop, halting ATP production by oxidative phosphorylation

Question 16

Which of the following is a facultative anaerobe?

Accepted Answer

A cell that can switch between fermentation and aerobic respiration depending on oxygen availability

Question 17

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 energy release when electrons are transferred to it

Question 18

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

Accepted Answer

Glucose

Question 19

Which process is responsible for the majority of ATP production during cellular respiration?

Accepted Answer

Oxidative phosphorylation

Question 20

If a mutation caused the mitochondrial inner membrane to become permeable to protons, what would be the most likely effect?

Accepted Answer

ATP production by ATP synthase would decrease due to loss of the proton gradient

Cellular Respiration and Fermentation: Pathways for ATP Production

Study Guide - Practice Questions