Q: Which of the following equations represents ATP synthesis from ADP and inorganic phosphate?

$$\mathrm{ADP} + \mathrm{Pi} + \text{Energy} \rightarrow \mathrm{ATP}$$

Question 1

Which of the following best describes the process of oxidation in cellular metabolism?

Accepted Answer

The loss of electrons by a molecule.

Question 2

During glycolysis, glucose is converted into pyruvate. Before entering the Krebs cycle, pyruvate undergoes which transformation?

Accepted Answer

It is oxidized and decarboxylated to form acetyl-CoA.

Question 3

Which equation correctly represents the conversion of NADH to NAD$$^+$$ during a redox reaction?

Accepted Answer

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

Question 4

A competitive inhibitor affects enzyme activity by:

Accepted Answer

Binding to the enzyme's active site, preventing substrate binding.

Question 5

Which of the following best explains why mesophilic bacteria are more susceptible to denaturation at temperatures above 45°C compared to thermophiles?

Accepted Answer

Mesophiles have enzymes with weaker hydrogen bonds that break at lower temperatures.

Question 6

Which of the following is TRUE regarding the electron transport chain (ETC) in aerobic respiration?

Accepted Answer

Oxygen acts as the final electron acceptor, forming water.

Question 7

A facultative anaerobe is placed in a test tube with an oxygen gradient. Where would you expect most growth?

Accepted Answer

Throughout the tube, but more at the top where oxygen is highest.

Question 8

During the log (exponential) phase of bacterial growth, which of the following is TRUE?

Accepted Answer

Cells are dividing rapidly and are most susceptible to antibiotics targeting cell wall synthesis.

Question 9

Which of the following media would best be used to culture obligate anaerobes?

Accepted Answer

Reducing media

Question 10

Which of the following equations represents ATP synthesis from ADP and inorganic phosphate?

Accepted Answer

$$\mathrm{ADP} + \mathrm{Pi} + 	ext{Energy} ightarrow \mathrm{ATP}$$

Question 11

Which physical method is most effective for sterilizing medical instruments contaminated with bacterial endospores?

Accepted Answer

Moist heat (autoclaving)

Question 12

A biofilm in a freshwater stream is likely to contain which of the following characteristics?

Accepted Answer

Microbes embedded in a matrix, increased resistance to disinfectants, and enhanced nutrient trapping.

Question 13

Which of the following best describes the role of cofactors in enzyme activity?

Accepted Answer

Cofactors are non-protein molecules that assist enzymes in catalysis.

Question 14

Which of the following is a correct match between microbial oxygen requirement and growth pattern in a test tube?

Accepted Answer

Obligate aerobes: growth only at the top of the tube.

Question 15

Which of the following statements about fermentation is TRUE?

Accepted Answer

Fermentation regenerates NAD$$^+$$ from NADH, allowing glycolysis to continue in the absence of oxygen.

Question 16

A hypertonic environment (high salt or sugar) preserves food by:

Accepted Answer

Causing water to leave microbial cells, leading to plasmolysis and inhibition of growth.

Question 17

Which of the following is NOT a product of heterofermentative bacterial fermentation?

Accepted Answer

Acetyl-CoA

Question 18

Which of the following best describes the difference between sterilization and disinfection?

Accepted Answer

Sterilization destroys all forms of microbial life, including endospores; disinfection eliminates most pathogens but not endospores.

Question 19

Lactobacillus is an aerotolerant anaerobe and heterofermentative. Which of the following best describes its metabolism?

Accepted Answer

It uses fermentation to produce lactic acid, ethanol, and CO$$_2$$ from glucose, and can survive in the presence of oxygen.

Question 20

Which of the following best explains why bacteria are most susceptible to penicillin during the log phase?

Accepted Answer

Penicillin targets cell wall synthesis, which is most active during rapid cell division.

Microbial Metabolism, Growth, and Control: Study Guide for Exam 2

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