Question 1

Which of the following best describes a facultative anaerobe?

Accepted Answer

An organism that can use oxygen but can also grow without it.

Question 2

A microbiologist wants to isolate a single colony from a mixed culture. Which technique should they use?

Accepted Answer

Streak plate method.

Question 3

Which of the following media is best described as having all chemical components known and precisely measured?

Accepted Answer

Defined media

Question 4

A bacterium is found growing optimally at 75°C. How would you classify it?

Accepted Answer

Hyperthermophile

Question 5

Which statement best explains why low temperatures can inhibit microbial growth?

Accepted Answer

Low temperatures cause membranes to become rigid and fragile, impairing function.

Question 6

Which formula correctly calculates the final number of cells in a population after n generations, given an initial population $$P_i$$?

Accepted Answer

$$P_f = P_i 	imes 2$$^{n}$$

Question 7

During which phase of the bacterial growth curve is the rate of cell division highest?

Accepted Answer

Log (exponential) phase

Question 8

Which of the following best describes the phenomenon of quorum sensing?

Accepted Answer

Bacteria communicate via chemical signals to coordinate group behavior.

Question 9

A microbiologist wants to grow only Gram-negative bacteria from a mixed sample. Which type of medium should they use?

Accepted Answer

Selective medium

Question 10

Which term describes a group of microorganisms all originating from a single cell or group of cells growing on a solid surface?

Accepted Answer

Colony

Question 11

Which of the following is NOT a correct pairing of microorganism type and optimal temperature range?

Accepted Answer

Psychrophile: 40°C–10°C

Question 12

Which of the following statements about oxygen and microbial growth is correct?

Accepted Answer

Facultative anaerobes can grow with or without oxygen.

Question 13

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

Accepted Answer

Stationary phase

Question 14

Which of the following is a real-world example of differential media?

Accepted Answer

A medium that changes color when bacteria ferment lactose.

Question 15

Why is water necessary for maintaining the integrity of microbial cells under osmotic pressure?

Accepted Answer

Water keeps the cell membrane stable and prevents collapse.

Question 16

Which of the following best describes binary fission?

Accepted Answer

A process where a prokaryotic cell divides into two daughter cells after DNA replication.

Question 17

A scientist wants to prevent contamination of sterile substances during an experiment. Which technique should they use?

Accepted Answer

Aspectic technique

Question 18

Which of the following is a consequence of denatured lipid membranes in bacteria due to high temperature?

Accepted Answer

Bacteria lose function and die.

Question 19

Which of the following best describes microbial growth?

Accepted Answer

Increase in number of cells.

Question 20

A culture medium contains peptone, beef extract, and agar, but the exact chemical composition is unknown. How is this medium classified?

Accepted Answer

Complex medium

Microbial Growth and Cultivation: Key Concepts and Processes

Study Guide - Practice Questions