Question 1

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

Accepted Answer

A single bacterial cell divides into two identical daughter cells after DNA replication and cytokinesis.

Question 2

During which phase of the bacterial population growth curve does the number of viable cells remain constant due to nutrient depletion and accumulation of waste products?

Accepted Answer

Stationary phase

Question 3

Which of the following bacterial arrangements is characterized by cocci arranged in grape-like clusters due to division in random planes?

Accepted Answer

Staphylococci

Question 4

A microbiologist is measuring the turbidity of a bacterial culture using a spectrophotometer. What is being measured in this process?

Accepted Answer

The optical density, which correlates with the total cell mass

Question 5

Which of the following best describes a chemoheterotroph?

Accepted Answer

Uses chemical compounds for energy and organic compounds as a carbon source

Question 6

A bacterium isolated from a hot spring grows optimally at 60°C. Which classification best describes this organism?

Accepted Answer

Thermophile

Question 7

Which of the following statements about obligate anaerobes is correct?

Accepted Answer

They grow only in the absence of oxygen and may be killed by its presence.

Question 8

Which of the following is a correct example of binomial nomenclature for a bacterial species?

Accepted Answer

Escherichia coli

Question 9

A patient presents with peptic ulcers. Which bacterium is most likely responsible, and what is a key feature of its survival in the stomach?

Accepted Answer

Helicobacter pylori; it produces urease to neutralize stomach acid

Question 10

Which of the following best describes the role of Rhizobium bacteria in agriculture?

Accepted Answer

They fix atmospheric nitrogen into a form usable by plants.

Question 11

Which of the following is a distinguishing feature of Mycoplasma species compared to other bacteria?

Accepted Answer

They lack a cell wall and are pleomorphic.

Question 12

A bacterium that grows optimally at pH 9.0 is best classified as a(n):

Accepted Answer

Alkaliphile

Question 13

Which of the following is true regarding endospore formation in bacteria?

Accepted Answer

Endospores are dormant, resistant structures formed in response to harsh conditions.

Question 14

Which of the following bacteria is a spirochete responsible for Lyme disease?

Accepted Answer

Borrelia burgdorferi

Question 15

A microbiologist is studying a bacterium that can survive in high salt concentrations but does not require salt for growth. This bacterium is best described as:

Accepted Answer

Facultative halophile

Question 16

Which of the following methods would be most appropriate for directly counting the number of bacterial cells in a sample?

Accepted Answer

Using a Petroff-Hauser counting chamber

Question 17

Which of the following statements about Archaea is correct?

Accepted Answer

They often live in extreme environments such as high temperature or high salinity.

Question 18

Which of the following is a medically important facultative anaerobic gram-negative rod commonly found in the human intestinal tract?

Accepted Answer

Escherichia coli

Question 19

A scientist isolates a bacterium that uses sunlight for energy and organic compounds as a carbon source. This bacterium is best classified as a:

Accepted Answer

Photoheterotroph

Question 20

Which of the following is a correct sequence for the taxonomic classification of Escherichia coli from domain to species?

Accepted Answer

Domain → Kingdom → Phylum → Class → Order → Family → Genus → Species

Bacteria and Archaea: Structure, Growth, and Classification

Study Guide - Practice Questions

Study Guide - Flashcards