Question 1

Which of the following best describes a biofilm, as shown in the first image?

Accepted Answer

A structured community of microbial cells enclosed in a self-produced polymeric matrix attached to a surface

Question 2

What is the primary function of superoxide dismutase in aerobic microorganisms?

Accepted Answer

To break down toxic superoxide radicals into less harmful molecules

Question 3

A microorganism that grows optimally at pH 9.0 is classified as:

Accepted Answer

Alkaliphile

Question 4

Which of the following equations represents the reaction catalyzed by catalase?

Accepted Answer

$$2\ H_2O_2 \rightarrow 2\ H_2O + O_2$

Question 5

Which type of culture media would you use to distinguish between bacteria based on their ability to hemolyze red blood cells?

Accepted Answer

Differential media

Question 6

In the nitrogen cycle, which process is carried out by denitrifying bacteria?

Accepted Answer

Conversion of nitrate to atmospheric nitrogen

Question 7

Which of the following is a trace element required by microorganisms for enzyme function?

Accepted Answer

Iron

Question 8

A bacterial culture is placed in a hypertonic solution. What is the most likely outcome?

Accepted Answer

Cells will shrink due to water loss

Question 9

Which of the following best describes the lag phase in a typical microbial growth curve?

Accepted Answer

Cells are adapting to the environment and not dividing rapidly

Question 10

Which method is considered an indirect measurement of microbial growth?

Accepted Answer

Turbidity measurement

Question 11

A microorganism that requires oxygen for growth but can survive in low oxygen environments is classified as:

Accepted Answer

Facultative anaerobe

Question 12

Which of the following is a function of riboflavin (vitamin B2) in microbial cells?

Accepted Answer

Precursor of FAD

Question 13

What is the main advantage of using lyophilization for preserving microbial cultures?

Accepted Answer

It preserves cultures for decades by removing water and freezing

Question 14

Which of the following best explains why lipid-containing membranes are sensitive to temperature changes?

Accepted Answer

Low temperatures cause membranes to become rigid and high temperatures cause them to become too fluid

Question 15

Which of the following is NOT a function of phosphorus in microbial cells?

Accepted Answer

Component of amino acids

Question 16

Which equation represents the reaction catalyzed by peroxidase?

Accepted Answer

$$H_2O_2 + 2\ H^+ \rightarrow 2\ H_2O$$

Question 17

Which of the following is a major reason why viruses cannot be grown on artificial media?

Accepted Answer

Viruses require living cells for replication

Question 18

A bacterial culture is grown in MacConkey agar. Which of the following is true about this medium?

Accepted Answer

It is both selective and differential

Question 19

Which of the following best describes the process of obtaining a pure culture from a mixed sample?

Accepted Answer

Streaking the sample on an agar plate to isolate colony-forming units

Question 20

If a bacterial culture has a generation time of 30 minutes, how many cells will be present after 2 hours if the initial population is 100 cells? (Assume exponential growth and no cell death)

Accepted Answer

$$100 	imes 2^4$ = 1600$$

Microbial Nutrition and Growth: Study Notes for College Microbiology

Study Guide - Practice Questions

Study Guide - Flashcards