Question 1

Which of the following best describes the role of oxygen in aerobic cellular respiration?

Accepted Answer

Oxygen is the final electron acceptor, combining with electrons and hydrogen ions to form water.

Question 2

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

Accepted Answer

$2$ ATP and $2$ NADH

Question 3

Which process in cellular respiration produces the majority of ATP?

Accepted Answer

Oxidative phosphorylation

Question 4

A patient is exposed to a toxin that inhibits ATP synthase. Which of the following will most directly decrease as a result?

Accepted Answer

The synthesis of ATP from ADP and $P_i$

Question 5

Which of the following statements about fermentation is correct?

Accepted Answer

Fermentation regenerates NAD+ by transferring electrons to an organic molecule.

Question 6

In the citric acid cycle, for each acetyl CoA that enters, what are the products generated?

Accepted Answer

$1$ ATP, $3$ NADH, $1$ FADH_2, $2$ CO_2

Question 7

Which of the following best explains why the exact number of ATP molecules generated from one molecule of glucose is not known?

Accepted Answer

The ratio of NADH to ATP is not a whole number and the proton-motive force can be used for other work.

Question 8

Which of the following is a key difference between aerobic respiration and fermentation?

Accepted Answer

Aerobic respiration uses oxygen as the final electron acceptor, while fermentation uses an organic molecule.

Question 9

A yeast cell is placed in an anaerobic environment. Which metabolic pathway will allow it to continue producing ATP?

Accepted Answer

Alcohol fermentation

Question 10

Which of the following best describes substrate-level phosphorylation?

Accepted Answer

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

Question 11

Which of the following is a real-life example of feedback inhibition in cellular respiration?

Accepted Answer

High levels of ATP inhibit phosphofructokinase, slowing glycolysis.

Question 12

Which of the following is true regarding the fate of pyruvate in the presence of oxygen in eukaryotic cells?

Accepted Answer

Pyruvate enters the mitochondrion and is converted to acetyl CoA.

Question 13

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

Accepted Answer

The electron transport chain is embedded in the inner mitochondrial membrane in eukaryotes.

Question 14

Which of the following is the correct sequence of events in aerobic cellular respiration?

Accepted Answer

Glycolysis $\rightarrow$ Pyruvate oxidation $\rightarrow$ Citric acid cycle $\rightarrow$ Oxidative phosphorylation

Question 15

Which of the following is a product of lactic acid fermentation?

Accepted Answer

Lactate

Question 16

In the absence of oxygen, how is NAD+ regenerated during fermentation?

Accepted Answer

By transferring electrons from NADH to pyruvate or its derivatives

Question 17

Which of the following best explains why fats yield more ATP per gram than carbohydrates?

Accepted Answer

Fats are more reduced and have more high-energy electrons for the electron transport chain.

Question 18

A facultative anaerobe such as yeast is placed in an environment with and without oxygen. What will determine whether it uses fermentation or cellular respiration?

Accepted Answer

The presence or absence of oxygen

Question 19

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

Accepted Answer

Glucose is oxidized and oxygen is reduced.

Question 20

If a drug acts as an uncoupler, allowing protons to diffuse across the mitochondrial membrane without passing through ATP synthase, what will happen to ATP synthesis and oxygen consumption?

Accepted Answer

ATP synthesis will decrease; oxygen consumption will greatly increase.

Cellular Respiration & Fermentation: Catabolic Pathways and Energy Harvest

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