Question 1

Which of the following best describes the role of enzymes in microbial metabolism?

Accepted Answer

Enzymes are organic catalysts that lower the activation energy, increasing the likelihood of a reaction proceeding.

Question 2

Which equation correctly represents the process of oxidation in metabolism?

Accepted Answer

$$\mathrm{Oxidation: \quad NADH \rightarrow NAD^+ + H^+ + 2e^-}$$

Question 3

A competitive inhibitor affects an enzyme by:

Accepted Answer

Binding to the active site, preventing substrate binding.

Question 4

Which of the following is NOT a product of glycolysis from one molecule of glucose?

Accepted Answer

Four molecules of ATP (net gain)

Question 5

During the energy-investment stage of glycolysis, which reaction occurs first?

Accepted Answer

Glucose is phosphorylated by ATP to form glucose-6-phosphate.

Question 6

Which of the following best explains why enzymes are specific for their substrates?

Accepted Answer

The enzyme's active site is complementary in shape to the substrate.

Question 7

Which of the following is a correct summary of the products generated from one turn of the Krebs cycle (TCA cycle) per acetyl-CoA?

Accepted Answer

2 CO$$_2$$, 3 NADH, 1 FADH$$_2$$, 1 ATP (or GTP)

Question 8

Which of the following statements about feedback inhibition is correct?

Accepted Answer

The end product binds to an allosteric site, causing a conformational change that reduces enzyme activity.

Question 9

Which of the following is an example of substrate-level phosphorylation?

Accepted Answer

$$\mathrm{ADP + P_i \rightarrow ATP}$$ during glycolysis

Question 10

A microorganism is exposed to a drug that distorts the active site of an essential enzyme. What is the most likely effect?

Accepted Answer

The enzyme will become inactive due to loss of substrate binding.

Question 11

Which of the following is a correct description of the lysis stage in glycolysis?

Accepted Answer

Fructose-1,6-bisphosphate is split into two three-carbon molecules.

Question 12

Which of the following is NOT a function of oxidoreductases?

Accepted Answer

Join two molecules together.

Question 13

If a bacterium is placed in an environment with a pH far outside its optimal range, what is the most likely effect on its enzymes?

Accepted Answer

Enzymes will denature and lose their activity.

Question 14

Which of the following is a real-world application of microbial metabolism discussed in the study materials?

Accepted Answer

Plastic-eating bacteria can help reduce waste.

Question 15

Which of the following is the correct sequence of stages in glycolysis?

Accepted Answer

Energy-investment stage, lysis stage, energy-conserving stage

Question 16

Which of the following statements about the ultimate goal of metabolism in microorganisms is correct?

Accepted Answer

The ultimate goal is the reproduction of the microorganism.

Question 17

Which of the following is true regarding the role of NAD$$^+ in $$the Krebs cycle?

Accepted Answer

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

Question 18

Which of the following is a plausible consequence of a mutation that prevents the synthesis of coenzymes in a bacterium?

Accepted Answer

The bacterium's enzymes may become inactive, halting metabolism.

Question 19

Which of the following is a correct description of the process of reduction in metabolism?

Accepted Answer

Reduction involves the gain of electrons.

Question 20

A patient is treated with Atovaquone, which kills parasites by interfering with their metabolism. What is the most likely mechanism of action?

Accepted Answer

Atovaquone inhibits enzymes in the electron transport chain.

Microbial Metabolism: Enzymes, Pathways, and Cellular Energy

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