Question 1

Which statement best describes the difference between catabolic and anabolic pathways in microbial metabolism?

Accepted Answer

Catabolic pathways hydrolyze bonds to break larger molecules into smaller products and are exergonic, while anabolic pathways synthesize large molecules from smaller products and are endergonic.

Question 2

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

Accepted Answer

$$2$$

Question 3

Which molecule acts as the universal cellular energy currency and is directly used to power cellular work such as active transport and biosynthesis?

Accepted Answer

ATP

Question 4

A patient is treated with an antimicrobial that acts as a competitive inhibitor of a key bacterial enzyme. What is the most likely mechanism of action?

Accepted Answer

The inhibitor binds to the enzyme's active site, preventing substrate binding.

Question 5

Which process in cellular respiration produces the greatest number of ATP molecules per molecule of glucose?

Accepted Answer

Oxidative phosphorylation (electron transport chain and chemiosmosis)

Question 6

In the electron transport chain of aerobic respiration, what is the final electron acceptor?

Accepted Answer

Oxygen ($$O_2)$$

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

A bacterium is found to use the Entner-Doudoroff pathway instead of glycolysis. What is a key difference in ATP yield between these two pathways?

Accepted Answer

The Entner-Doudoroff pathway produces only one ATP per glucose, while glycolysis produces two.

Question 9

Which metabolic process allows cells to regenerate NAD$$^+ in $$the absence of an electron transport chain?

Accepted Answer

Fermentation

Question 10

Which of the following is NOT a function of enzymes in cellular metabolism?

Accepted Answer

Being consumed during the reaction

Question 11

A microbe is classified as a chemoautotroph. What does this mean regarding its energy and carbon sources?

Accepted Answer

It uses inorganic chemicals for energy and carbon dioxide for carbon.

Question 12

Which of the following statements about the Calvin-Benson cycle is correct?

Accepted Answer

It fixes carbon dioxide to synthesize carbohydrates using ATP and NADPH.

Question 13

Which electron carrier is primarily loaded during the Krebs cycle and later donates electrons to the electron transport chain?

Accepted Answer

NADH

Question 14

A bacterium is exposed to a chemical that drastically lowers the pH of its environment. What is the most likely effect on its enzymes?

Accepted Answer

Enzymes will denature, leading to loss of catalytic activity.

Question 15

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

Accepted Answer

Glycolysis → Krebs cycle → Electron transport chain

Question 16

Which metabolic pathway is responsible for the synthesis of glucose from non-carbohydrate precursors?

Accepted Answer

Gluconeogenesis

Question 17

In photosynthetic organisms, what is the role of the thylakoid membrane?

Accepted Answer

It houses the light-harvesting complexes and electron transport chain for light-dependent reactions.

Question 18

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

Accepted Answer

The final product of a pathway binds to an enzyme early in the pathway, reducing its activity.

Question 19

Which process is responsible for the breakdown of fatty acids into two-carbon units that enter the citric acid cycle?

Accepted Answer

Beta-oxidation

Question 20

A microbe is classified as a photoheterotroph. Which of the following best describes its metabolic strategy?

Accepted Answer

It uses sunlight for energy and organic molecules for carbon.

Microbial Metabolism: Enzymes, Energy, and Metabolic Pathways

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