Q: Which equation best represents the overall reaction of glycolysis?

$ \text{Glucose} + 2 \text{NAD}^+ + 2 \text{ADP} + 2 \text{P}_i \rightarrow 2 \text{Pyruvate} + 2 \text{NADH} + 2 \text{ATP} + 2 \text{H}_2\text{O} $

Question 1

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

Accepted Answer

ATP serves as the primary energy currency, transferring energy between catabolic and anabolic reactions.

Question 2

During aerobic respiration, electrons are transferred from NADH to oxygen via the electron transport chain (ETC). What is the main consequence of this electron transfer?

Accepted Answer

It generates a proton gradient across the membrane, which is used to produce ATP.

Question 3

Which equation correctly represents the net ATP yield from aerobic respiration of one glucose molecule in bacteria?

Accepted Answer

$ 1 	imes 38 = 38 $

Question 4

Which process allows cells to regenerate NAD+ in the absence of oxygen?

Accepted Answer

Fermentation

Question 5

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

Accepted Answer

Fermentation

Question 6

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

Accepted Answer

The ETC transfers electrons from high to low redox potential, releasing energy.

Question 7

Which of the following is a correct description of chemolithotrophs?

Accepted Answer

Organisms that use inorganic molecules as energy sources and electron donors.

Question 8

Which equation best represents the overall reaction of glycolysis?

Accepted Answer

$ 	ext{Glucose} + 2 	ext{NAD}^+ + 2 	ext{ADP} + 2 	ext{P}_i ightarrow 2 	ext{Pyruvate} + 2 	ext{NADH} + 2 	ext{ATP} + 2 	ext{H}_2	ext{O} $

Question 9

In the context of microbial metabolism, what is the main function of fermentation?

Accepted Answer

To regenerate NAD$^+$ from NADH, allowing glycolysis to continue in the absence of an electron transport chain.

Question 10

Which of the following best explains why biogeochemical cycles do not occur independently in nature?

Accepted Answer

Microbial communities are interconnected, and the products of one cycle often serve as substrates for another.

Question 11

Which of the following is a key difference between phototrophs and chemotrophs?

Accepted Answer

Phototrophs use light energy for electron transfer, while chemotrophs use chemical energy.

Question 12

A mutation disables the ATP synthase enzyme in a bacterium. What is the most likely consequence?

Accepted Answer

The cell will be unable to synthesize ATP via oxidative phosphorylation.

Question 13

Which of the following is true regarding the coupling of electron transfer to proton translocation in the ETC?

Accepted Answer

Electron transfer in the ETC is directly coupled to the movement of protons across the membrane, creating a proton motive force.

Question 14

Which of the following best describes the role of NAD$^+$ in cellular metabolism?

Accepted Answer

NAD$^+$ acts as an electron acceptor, becoming reduced to NADH during catabolic reactions.

Question 15

Which of the following is a correct statement about the TCA (Krebs) cycle?

Accepted Answer

The TCA cycle oxidizes acetyl-CoA to CO$_2$, generating NADH and FADH$_2$ for the electron transport chain.

Question 16

Which equation represents the conversion of pyruvate to acetyl-CoA during pyruvate oxidation?

Accepted Answer

$ 	ext{Pyruvate} + 	ext{NAD}^+ + 	ext{CoA} ightarrow 	ext{Acetyl-CoA} + 	ext{NADH} + 	ext{CO}_2 $

Question 17

Which of the following is a characteristic of methanogens in the carbon cycle?

Accepted Answer

They produce methane by reducing CO$_2$ with hydrogen.

Question 18

Which of the following is a correct statement about substrate-level phosphorylation?

Accepted Answer

It is the direct transfer of a phosphate group to ADP from a phosphorylated intermediate.

Question 19

A patient presents with lactic acidosis after intense exercise. Which metabolic pathway is most likely responsible for the accumulation of lactic acid?

Accepted Answer

Fermentation

Question 20

Which of the following best explains why anaerobic respiration yields less ATP than aerobic respiration?

Accepted Answer

Anaerobic respiration uses electron acceptors with lower redox potential than oxygen, resulting in less energy released per electron transferred.

Microbial Metabolism and Energy Generation: Study Notes

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