Question 1

Which of the following best describes the difference between catabolism and anabolism in microbial metabolism?

Accepted Answer

Catabolism breaks down large molecules to release energy, while anabolism uses energy to build large molecules from smaller ones.

Question 2

A bacterium that uses sunlight as an energy source and carbon dioxide as a carbon source is classified as a:

Accepted Answer

Photoautotroph

Question 3

Which equation correctly represents the phosphorylation of ADP to ATP?

Accepted Answer

$$\mathrm{ADP} + \mathrm{phosphate} + \mathrm{energy} \rightarrow \mathrm{ATP}$$

Question 4

Which process allows certain microbes to convert atmospheric nitrogen ($$\mathrm{N}_2) $$into ammonia usable by plants?

Accepted Answer

Nitrogen fixation

Question 5

During aerobic respiration, what is the final electron acceptor in the electron transport chain?

Accepted Answer

Oxygen ($$\mathrm{O}_2)$$

Question 6

Which of the following statements about enzymes is TRUE?

Accepted Answer

Enzymes lower the activation energy ($$E_a) $$required for a reaction.

Question 7

A microbe living in a hydrothermal vent uses hydrogen sulfide as an energy source and carbon dioxide as a carbon source. What is its nutritional classification?

Accepted Answer

Chemoautotroph (Chemolithotroph)

Question 8

Which of the following best explains why compost piles can become hot during microbial decomposition?

Accepted Answer

Some energy from microbial metabolism is lost as heat during stepwise breakdown of organic matter.

Question 9

In fermentation, how is NAD$$^+$$ regenerated to allow glycolysis to continue?

Accepted Answer

By transferring electrons from NADH to an internal organic molecule such as pyruvate.

Question 10

Which of the following is an example of feedback inhibition in a metabolic pathway?

Accepted Answer

The final product of a pathway binding to the first enzyme and shutting down the pathway.

Question 11

Which equation represents the hydrolysis of ATP to release energy for cellular work?

Accepted Answer

$$\mathrm{ATP} \rightarrow \mathrm{ADP} + \mathrm{phosphate} + \mathrm{energy}$$

Question 12

Which of the following is a unique metabolic capability of certain Archaea but not found in plants or animals?

Accepted Answer

Methanogenesis

Question 13

A microbe is found to use glucose as a carbon source and nitrate ($$\mathrm{NO}_3^-) as a $$terminal electron acceptor. Which metabolic process is it most likely performing?

Accepted Answer

Anaerobic respiration

Question 14

Which statement best describes the role of NADH and FADH$$_2 in $$cellular respiration?

Accepted Answer

They carry high-energy electrons to the electron transport chain for ATP production.

Question 15

Which of the following is an example of allosteric regulation?

Accepted Answer

A molecule binds to a site other than the active site, changing the enzyme's shape and activity.

Question 16

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

Accepted Answer

They allow chemical reactions to occur at cell-friendly temperatures by lowering activation energy ($$E_a).$$

Question 17

Which of the following scenarios illustrates the coupling of reactions by an enzyme?

Accepted Answer

An enzyme uses the energy released from ATP hydrolysis to drive the synthesis of a protein.

Question 18

Which of the following is a real-world application of microbial metabolism in environmental cleanup?

Accepted Answer

Microbes breaking down plastics and toxic chemicals in bioremediation.

Question 19

Which of the following best describes the ATP/ADP cycle in cells?

Accepted Answer

ATP is constantly recycled by coupling energy-releasing and energy-requiring reactions.

Microbial Metabolism: Classification, Energy Pathways, and Enzyme Regulation

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