Question 1

Which of the following best describes the main function of ATP in microbial cells?

Accepted Answer

ATP serves as the primary energy currency, coupling catabolic and anabolic reactions.

Question 2

A bacterium is found growing only at the bottom of a thioglycolate broth tube (as seen in tube E of the image). What is the most likely oxygen requirement for this organism?

Accepted Answer

Obligate anaerobe

Question 3

Which of the following equations correctly represents the exponential growth of a bacterial population?

Accepted Answer

$$N_T = (N_0$)2^{t/d}$

Question 4

Which metabolic pathway is primarily responsible for generating NADPH and ribose-5-phosphate, rather than ATP, from glucose?

Accepted Answer

Pentose phosphate pathway

Question 5

A culture is grown on MacConkey agar and produces bright pink colonies. What does this indicate about the organism?

Accepted Answer

It is Gram-negative and ferments lactose.

Question 6

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

Accepted Answer

Glycolysis → TCA cycle → Electron transport chain

Question 7

Which enzyme is responsible for unzipping the DNA double helix during bacterial DNA replication?

Accepted Answer

Helicase

Question 8

A patient sample is streaked on blood agar. Colonies surrounded by a clear, colorless zone are observed. What type of hemolysis is this?

Accepted Answer

Beta (β) hemolysis

Question 9

Which of the following statements about fermentation is TRUE?

Accepted Answer

Fermentation produces less ATP per glucose than aerobic respiration.

Question 10

A bacterial culture starts with 100 cells and has a doubling time of 30 minutes. How many cells will there be after 3 hours?

Accepted Answer

6400

Question 11

Which of the following best explains why obligate anaerobes cannot survive in the presence of oxygen?

Accepted Answer

They lack the enzymes superoxide dismutase and catalase.

Question 12

Which of the following is a selective and differential medium for Gram-negative bacteria and lactose fermentation?

Accepted Answer

MacConkey agar

Question 13

Which of the following is the correct net ATP yield from complete aerobic respiration of one molecule of glucose in bacteria?

Accepted Answer

$$38$$

Question 14

Which of the following best describes the role of the electron transport chain in aerobic respiration?

Accepted Answer

It generates a proton gradient used to synthesize ATP.

Question 15

Which of the following is NOT a product of the tricarboxylic acid (TCA) cycle?

Accepted Answer

Lactate

Question 16

A bacterial culture is grown in a medium containing only inorganic compounds as energy and carbon sources. Which nutritional type does this describe?

Accepted Answer

Chemoautotroph

Question 17

Which of the following best describes the function of superoxide dismutase in aerobic bacteria?

Accepted Answer

It detoxifies superoxide radicals produced during oxygen metabolism.

Question 18

Which phase of the bacterial growth curve is characterized by a balance between cell division and cell death?

Accepted Answer

Stationary phase

Question 19

Which of the following best explains why the removal of the terminal phosphate from ATP releases energy?

Accepted Answer

The bond between the second and third phosphate is a high-energy bond due to electrostatic repulsion.

Question 20

Which of the following best describes the main purpose of using selective media in microbiology?

Accepted Answer

To suppress the growth of unwanted organisms while allowing the target organism to grow

Microbial Metabolism and Growth: Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards