Question 1

Which of the following best describes the ultimate function of metabolism in a microbial cell?

Accepted Answer

To reproduce the organism

Question 2

Which statement correctly distinguishes catabolic from anabolic pathways?

Accepted Answer

Catabolic pathways break larger molecules into smaller products and are exergonic, while anabolic pathways build larger molecules and are endergonic.

Question 3

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

Accepted Answer

$$2$$ ATP and $$2$$ NADH

Question 4

Which of the following is NOT a correct pairing of an electron carrier with its abbreviation?

Accepted Answer

Adenosine diphosphate (ADP)

Question 5

A scientist is studying a bacterium that can grow in the absence of oxygen by using nitrate as a final electron acceptor. Which process is this bacterium performing?

Accepted Answer

Anaerobic respiration

Question 6

Which of the following best explains why enzymes are essential for metabolic reactions?

Accepted Answer

They lower the activation energy, increasing the likelihood of reactions.

Question 7

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

Accepted Answer

ATP is generated by the direct transfer of a phosphate group from a substrate to ADP.

Question 8

Apoenzymes require which of the following to become functional holoenzymes?

Accepted Answer

Binding to a cofactor or coenzyme

Question 9

Which of the following is NOT a factor that influences the rate of enzymatic reactions?

Accepted Answer

The genetic code of the organism

Question 10

In the electron transport chain, what is the main function of the proton gradient established across the membrane?

Accepted Answer

To drive the synthesis of ATP via ATP synthase

Question 11

Which of the following best describes feedback inhibition in metabolic pathways?

Accepted Answer

The end product of a pathway inhibits an enzyme earlier in the pathway.

Question 12

A bacterium is found to use the Entner-Doudoroff pathway instead of glycolysis. Which of the following is a likely consequence?

Accepted Answer

It will produce fewer ATP molecules per glucose molecule.

Question 13

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

Accepted Answer

Glycolysis $$\rightarrow$$ Synthesis of acetyl-CoA $$\rightarrow$$ Krebs cycle $$\rightarrow$$ Electron transport chain

Question 14

Which of the following is true regarding fermentation?

Accepted Answer

It allows cells to regenerate NAD$$^+ in $$the absence of a functional electron transport chain.

Question 15

Which of the following is an example of an amphibolic pathway?

Accepted Answer

The Krebs cycle

Question 16

A cell is exposed to a noncompetitive inhibitor. What is the most likely effect on the enzyme's activity?

Accepted Answer

The inhibitor binds to an allosteric site, changing the enzyme's shape and reducing activity.

Question 17

Which of the following best explains why cells regulate metabolic pathways at multiple levels (gene expression and enzyme activity)?

Accepted Answer

To ensure that enzymes are only produced and active when needed, conserving energy and resources.

Question 18

Which of the following is NOT a product of the Krebs cycle per molecule of glucose?

Accepted Answer

$$6$$ $$CO_2$

Question 19

A patient is diagnosed with a mitochondrial disorder that impairs the electron transport chain. Which of the following would most likely be observed in their cells?

Accepted Answer

Decreased ATP production due to impaired oxidative phosphorylation

Question 20

Which of the following statements about chemiosmosis is correct?

Accepted Answer

It uses the energy of a proton gradient to drive the phosphorylation of ADP to ATP.

CH 5. Microbial Metabolism: Fundamental Chemical Reactions and Pathways

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