Question 1

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

Accepted Answer

$2$ ATP and $2$ NADH

Question 2

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

Accepted Answer

It serves as the final electron acceptor in the electron transport chain.

Question 3

A bacterium is growing in an environment lacking oxygen but still needs to generate ATP. Which metabolic pathway is it most likely to use?

Accepted Answer

Fermentation

Question 4

Which of the following is a correct summary of the energy investment and payoff phases of glycolysis for one molecule of glucose?

Accepted Answer

Investment: $-2$ ATP; Payoff: $+4$ ATP, $+2$ NADH; Net: $+2$ ATP, $+2$ NADH

Question 5

In the Krebs cycle, what are the products generated from one molecule of acetyl-CoA?

Accepted Answer

$2$ CO$_2$, $3$ NADH, $1$ FADH$_2$, $1$ ATP

Question 6

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

Accepted Answer

The ETC uses redox reactions to create a proton gradient across a membrane, which drives ATP synthesis.

Question 7

How many ATP molecules are typically produced from one molecule of NADH and one molecule of FADH$_2$ via the electron transport chain?

Accepted Answer

$3$ ATP from NADH and $2$ ATP from FADH$_2$

Question 8

Which of the following best explains why fermentation is necessary in the absence of oxygen?

Accepted Answer

It regenerates NAD$^+$ needed for glycolysis to continue.

Question 9

A microbe that uses light as its energy source and CO$_2$ as its carbon source is classified as a:

Accepted Answer

Photoautotroph

Question 10

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

Accepted Answer

Aerobic respiration uses O$_2$ as the final electron acceptor, while anaerobic respiration uses molecules like NO$_3^-$ or SO$_4^{2-}$.

Question 11

Which of the following best describes the main function of the proton gradient generated by the electron transport chain?

Accepted Answer

It drives the synthesis of ATP via ATP synthase.

Question 12

A chemoheterotroph obtains its energy and carbon from which sources?

Accepted Answer

Chemical compounds for energy and organic compounds for carbon

Question 13

Which of the following is a real-world example of a fermentation product used in industry?

Accepted Answer

Ethanol in alcoholic beverages

Question 14

If a cell is unable to regenerate NAD$^+$, which metabolic pathway will be directly affected first?

Accepted Answer

Glycolysis

Question 15

Which of the following statements about microbial growth is correct?

Accepted Answer

Microbial growth refers to an increase in the number of cells.

Question 16

A green sulfur bacterium uses light for energy and H$_2$S as an electron donor, but does not produce O$_2$. How is it classified?

Accepted Answer

Photoautotroph

Question 17

Which of the following best explains why understanding microbial metabolism is important in food safety?

Accepted Answer

It helps identify ways to alter microbial growth and prevent foodborne illness.

Question 18

Which of the following is NOT a product of the Krebs cycle per molecule of acetyl-CoA?

Accepted Answer

O$_2$

Question 19

A microbe that uses organic compounds as both its energy and carbon source, and can grow in the absence of oxygen by fermentation, is best classified as a:

Accepted Answer

Chemoheterotroph

Question 20

Which of the following equations correctly represents the net ATP yield from complete aerobic respiration of one molecule of glucose in a prokaryotic cell?

Accepted Answer

$C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + 38ATP$

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