It is oxidized to NAD\textsuperscript{+}

$$2 \text{pyruvate} + 2 \text{NADH} \rightarrow 2 \text{ethanol} + 2 \text{CO}_2 + 2 \text{NAD}^+$$

$$2 \text{pyruvate} + 2 \text{NADH} \rightarrow 2 \text{lactate} + 2 \text{NAD}^+$$

Question 1

Which of the following is a product of alcoholic fermentation in yeast cells?

Accepted Answer

Ethanol

Question 2

During alcoholic fermentation, what is the fate of NADH?

Accepted Answer

It is oxidized to NAD	extsuperscript{+}

Question 3

Which equation correctly represents the overall reaction for alcoholic fermentation?

Accepted Answer

$$2 	ext{pyruvate} + 2 	ext{NADH} ightarrow 2 	ext{ethanol} + 2 	ext{CO}_2 + 2 	ext{NAD}^+$$

Question 4

In lactic acid fermentation, which molecule is directly reduced by NADH?

Accepted Answer

Pyruvate

Question 5

Which of the following best describes the role of fermentation in cellular metabolism?

Accepted Answer

It regenerates NAD$$^+$$ for glycolysis

Question 6

What is the main difference between alcoholic fermentation and lactic acid fermentation?

Accepted Answer

Alcoholic fermentation releases CO$$_2$$, while lactic acid fermentation does not

Question 7

Which enzyme is responsible for converting pyruvate to ethanol in alcoholic fermentation?

Accepted Answer

Alcohol dehydrogenase

Question 8

Why is fermentation necessary under anaerobic conditions?

Accepted Answer

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

Question 9

A patient with a deficiency in lactate dehydrogenase would have trouble performing which process?

Accepted Answer

Lactic acid fermentation

Question 10

Which of the following statements about fermentation is FALSE?

Accepted Answer

Fermentation converts pyruvate to acetyl-CoA

Question 11

During strenuous exercise, muscle cells switch to lactic acid fermentation. What is the immediate benefit of this switch?

Accepted Answer

Regeneration of NAD$$^+ to $$allow glycolysis to continue

Question 12

Which of the following is NOT a product of lactic acid fermentation?

Accepted Answer

CO$$_2$$

Question 13

In alcoholic fermentation, which step releases CO$$_2$$?

Accepted Answer

Conversion of pyruvate to acetaldehyde

Question 14

Which of the following equations represents lactic acid fermentation?

Accepted Answer

$$2 	ext{pyruvate} + 2 	ext{NADH} ightarrow 2 	ext{lactate} + 2 	ext{NAD}^+$$

Question 15

Which process is most likely to occur in human muscle cells under anaerobic conditions?

Accepted Answer

Lactic acid fermentation

Question 16

What is the primary purpose of converting pyruvate to lactate or ethanol during fermentation?

Accepted Answer

To regenerate NAD$$^+$$ for glycolysis

Question 17

Which of the following statements best explains why yeast cells perform alcoholic fermentation?

Accepted Answer

To regenerate NAD$$^+ in $$the absence of oxygen

Question 18

A mutation in the gene encoding alcohol dehydrogenase would most directly affect which process?

Accepted Answer

Conversion of acetaldehyde to ethanol

Question 19

Which of the following is a common misconception about fermentation?

Accepted Answer

Fermentation produces large amounts of ATP

Question 20

In alcoholic fermentation, which intermediate is formed between pyruvate and ethanol?

Accepted Answer

Acetaldehyde

Fermentation Pathways in Biochemistry

Study Guide - Practice Questions