Question 1

Which of the following best describes a macronutrient in microbial nutrition?

Accepted Answer

A substance required in large quantities, playing principal roles in cell structure and metabolism.

Question 2

A bacterium is placed in a solution with a higher solute concentration than its cytoplasm. What is the expected effect on the cell?

Accepted Answer

Water will diffuse out of the cell, potentially leading to plasmolysis.

Question 3

Which equation correctly represents the reaction carried out by methanogens?

Accepted Answer

$$4H_2 + CO_2$ \rightarrow CH_4$ + 2H_2O$$

Question 4

Which of the following is NOT a characteristic of facilitated diffusion?

Accepted Answer

It requires energy in the form of ATP.

Question 5

A facultative anaerobe is placed in an environment with no oxygen. What metabolic process will it most likely use?

Accepted Answer

Fermentation

Question 6

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

Accepted Answer

They lack enzymes to detoxify reactive oxygen species.

Question 7

Which phase of the bacterial growth curve is characterized by rapid cell division and maximum metabolic activity?

Accepted Answer

Log (exponential) phase

Question 8

A bacterial culture is growing in a chemostat. What is the main advantage of this system?

Accepted Answer

It maintains the culture in a biochemically active state by stabilizing growth rate and cell number.

Question 9

Which of the following is a correct description of a halophile?

Accepted Answer

An organism that thrives in environments with high salt concentrations.

Question 10

Which process is used by amoebas and certain white blood cells to ingest large solid particles?

Accepted Answer

Phagocytosis

Question 11

A bacterial cell is placed in a hypotonic solution. What adaptation allows bacteria to survive this environment?

Accepted Answer

A rigid cell wall prevents the cell from bursting.

Question 12

Which of the following is a trace element (micronutrient) important for enzyme function?

Accepted Answer

Iron

Question 13

Which of the following equations represents the action of catalase in detoxifying hydrogen peroxide?

Accepted Answer

$$2H_2O_2 \rightarrow 2H_2O + O_2$

Question 14

Which microbial association is characterized by both members benefiting from the relationship?

Accepted Answer

Mutualism

Question 15

Which of the following best describes the role of phosphorus in microbial cells?

Accepted Answer

It is a major component of nucleic acids and ATP.

Question 16

A researcher wants to rapidly quantify the number of bacteria in a pharmaceutical sample without culturing. Which method should they use?

Accepted Answer

Polymerase chain reaction (PCR)

Question 17

Which of the following terms describes an organism that uses inorganic CO$$_2 as $$its carbon source and light as its energy source?

Accepted Answer

Photoautotroph

Question 18

During which phase of the bacterial growth curve are cells most susceptible to antimicrobial agents?

Accepted Answer

Log (exponential) phase

Question 19

Which of the following is a correct statement about biofilms?

Accepted Answer

Biofilms are mixed communities of microbes that communicate via quorum sensing.

Question 20

A bacterial population doubles every 30 minutes. If you start with 100 cells, how many cells will there be after 2 hours?

Accepted Answer

1600

Microbial Nutrition and Growth: Key Concepts and Mechanisms

Study Guide - Practice Questions