Q: Which of the following equations represents the conversion of pyruvate to ethanol during alcohol fermentation?

$$2 \text{Pyruvate} \rightarrow 2 \text{Acetaldehyde} \rightarrow 2 \text{Ethanol}$$

Question 1

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

Accepted Answer

Oxygen is the final electron acceptor in the electron transport chain (ETC).

Question 2

In anaerobic respiration, which molecules commonly serve as the final electron acceptors instead of oxygen?

Accepted Answer

Sulfates and nitrates

Question 3

Which process generates ATP without the use of an electron transport chain (ETC)?

Accepted Answer

Fermentation

Question 4

During strenuous exercise, muscle cells switch to lactic acid fermentation. What is the primary reason for this metabolic shift?

Accepted Answer

To generate ATP when oxygen is limited

Question 5

Which of the following equations correctly represents the net ATP yield from glycolysis followed by lactic acid fermentation per glucose molecule?

Accepted Answer

$$2 \mathrm{ADP} + 2 \mathrm{P} \rightarrow 2 \mathrm{ATP}$$

Question 6

Alcohol fermentation in yeast results in the production of which two main products from pyruvate?

Accepted Answer

Ethanol and carbon dioxide

Question 7

What is the main function of fermentation in cells under anaerobic conditions?

Accepted Answer

To recycle NAD+ for continued glycolysis

Question 8

Which of the following best explains why lactic acid fermentation causes a burning sensation in muscles during intense exercise?

Accepted Answer

Accumulation of lactate lowers blood pH

Question 9

If lactate produced during lactic acid fermentation is not broken down efficiently in the liver, what condition can result?

Accepted Answer

Lactic acidosis

Question 10

Which of the following is TRUE regarding the location of fermentation in eukaryotic cells?

Accepted Answer

Fermentation occurs in the cytosol.

Question 11

A prokaryote living in a deep-sea vent environment with no oxygen uses anaerobic respiration. Which of the following is most likely to be its final electron acceptor?

Accepted Answer

Sulfate ($$SO_4$$^{2-}$$)

Question 12

Which of the following best describes the difference between anaerobic respiration and fermentation?

Accepted Answer

Anaerobic respiration uses an ETC; fermentation does not.

Question 13

During alcohol fermentation, which intermediate is formed before ethanol is produced?

Accepted Answer

Acetaldehyde

Question 14

Which of the following equations represents the conversion of pyruvate to ethanol during alcohol fermentation?

Accepted Answer

$$2 	ext{Pyruvate} ightarrow 2 	ext{Acetaldehyde} ightarrow 2 	ext{Ethanol}$$

Question 15

Which of the following is a real-life consequence of excessive lactate accumulation in the blood?

Accepted Answer

Excessively low blood pH (lactic acidosis)

Question 16

Which process is responsible for recycling NAD+ during fermentation?

Accepted Answer

Reduction of pyruvate to lactate or ethanol

Question 17

How many net ATP molecules are produced per glucose molecule during fermentation?

Accepted Answer

2

Question 18

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

Accepted Answer

Carbon dioxide

Question 19

Which pathway is used by yeast to produce ethanol in the absence of oxygen?

Accepted Answer

Alcohol fermentation

Question 20

A patient is diagnosed with lactic acidosis after a period of intense exercise. Which of the following best explains the biochemical cause?

Accepted Answer

Lactate produced in muscles accumulates in the blood, lowering pH.

Respiration Without Oxygen: Anaerobic Respiration and Fermentation

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