Question 1

Which of the following best describes the process of binary fission in bacteria?

Accepted Answer

A single cell divides into two identical cells, each originating from the parent cell.

Question 2

A microbiologist is culturing bacteria that require organic molecules for carbon and obtain energy from chemical compounds. Which classification best fits these bacteria?

Accepted Answer

Chemoheterotrophs

Question 3

Which equation represents the exponential growth of bacteria during the log phase, where $$N_0 is $$the initial number of cells, $$n is $$the number of generations, and $$N is $$the final number of cells?

Accepted Answer

$$N = N_0$ 	imes 2^n$$

Question 4

A bacterial species is found growing in a sealed jar with no oxygen present. When exposed to oxygen, the cells die. Which term best describes this organism?

Accepted Answer

Obligate anaerobe

Question 5

Which of the following is a major reason why biofilms are problematic in medical settings?

Accepted Answer

Biofilms allow microbes to share nutrients and resist antibiotics.

Question 6

A scientist is culturing halophiles. Which environmental condition must be provided for optimal growth?

Accepted Answer

High salt concentration

Question 7

Which of the following best explains why obligate anaerobes are harmed by oxygen?

Accepted Answer

They lack enzymes to neutralize toxic oxygen molecules such as superoxide radicals.

Question 8

A culture medium contains peptone, beef extract, and sodium chloride, but the exact chemical composition is unknown. Which type of media is this?

Accepted Answer

Complex media

Question 9

Which phase of the bacterial growth curve is characterized by cells adjusting to their environment and not actively dividing?

Accepted Answer

Lag phase

Question 10

A researcher wants to estimate the number of bacteria in a liquid culture by measuring its turbidity. Which method is being used?

Accepted Answer

Indirect measurement

Question 11

Which of the following best describes the function of growth factors in microbial nutrition?

Accepted Answer

Organic compounds that some organisms cannot synthesize and must obtain from the environment

Question 12

A bacterium is classified as a mesophile. Which temperature range would most likely support its growth?

Accepted Answer

20–40°C

Question 13

Which of the following media would best allow a microbiologist to distinguish between lactose fermenters and non-fermenters, while also inhibiting the growth of Gram-positive bacteria?

Accepted Answer

MacConkey agar

Question 14

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

Accepted Answer

Water leaves the cell, resulting in plasmolysis.

Question 15

Which of the following is a direct method for measuring microbial growth?

Accepted Answer

Plate count

Question 16

A scientist observes that a bacterial culture's growth rate equals its death rate. Which phase of the growth curve is the culture in?

Accepted Answer

Stationary phase

Question 17

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

Accepted Answer

It is required for the synthesis of proteins, DNA, and RNA.

Question 18

A microbe grows best at pH 2. Which term best describes this organism?

Accepted Answer

Acidophile

Question 19

A patient develops a persistent infection on a catheter. Which microbial structure is most likely responsible for the infection's resistance to antibiotics?

Accepted Answer

Biofilm

Question 20

A culture contains both obligate aerobes and facultative anaerobes. If oxygen is removed, what will happen to the growth of each type?

Accepted Answer

Obligate aerobes will die; facultative anaerobes will continue to grow.

Microbial Nutrition and Growth: Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards