Question 1

Which of the following best describes the main structural difference between Gram-positive and Gram-negative bacterial cell walls?

Accepted Answer

Gram-positive bacteria have a thick peptidoglycan layer and lack an outer membrane, while Gram-negative bacteria have a thin peptidoglycan layer and possess an outer membrane.

Question 2

A microbiologist is studying a bacterium that moves toward nutrients using a whip-like appendage. Which structure is primarily responsible for this movement, and what is the mechanism called?

Accepted Answer

Flagellum; chemotaxis

Question 3

Which of the following statements about endospores is correct?

Accepted Answer

Endospores are highly resistant structures formed by some bacteria to survive extreme conditions such as heat, desiccation, and radiation.

Question 4

Which of the following best explains why mitochondria and chloroplasts are considered to have evolved from prokaryotic cells?

Accepted Answer

They contain their own circular DNA and ribosomes similar to those found in bacteria.

Question 5

A patient is diagnosed with a bacterial infection caused by a species that stains purple with the Gram stain. Which of the following is most likely true about this bacterium?

Accepted Answer

It has a thick peptidoglycan layer and lacks an outer membrane.

Question 6

Which of the following is a key difference between bacterial and archaeal cell membranes?

Accepted Answer

Bacterial membranes contain ester-linked phospholipids, while archaeal membranes contain ether-linked lipids.

Question 7

A scientist is studying a newly discovered virus. The virus has a single-stranded RNA genome and replicates in the cytoplasm of host cells. Which family is this virus most likely to belong to?

Accepted Answer

Picornaviridae

Question 8

Which of the following best describes the function of bacterial glycocalyx?

Accepted Answer

It helps bacteria adhere to surfaces and protects them from desiccation and phagocytosis.

Question 9

Which of the following equations correctly represents the exponential growth of a bacterial population, where $$N_t is $$the number of cells at time $$t$$, $$N_0 is $$the initial number of cells, and $$n is $$the number of generations?

Accepted Answer

$$N_t = N_0$ 	imes 2^n$$

Question 10

A laboratory is culturing a bacterium that produces a purple pigment as a result of unique biochemistry. Which group does this bacterium most likely belong to?

Accepted Answer

Purple sulfur bacteria

Question 11

Which of the following statements about viruses is correct?

Accepted Answer

Viruses are not alive because they cannot carry out metabolism or reproduce independently.

Question 12

A patient is infected with a virus that can remain dormant in host cells and reactivate later, causing symptoms. What is this phenomenon called?

Accepted Answer

Latency

Question 13

Which of the following best describes the function of ribosomes in both prokaryotic and eukaryotic cells?

Accepted Answer

They are the sites of protein synthesis.

Question 14

Which of the following is a key structural feature found in eukaryotic cells but not in prokaryotic cells?

Accepted Answer

Membrane-bound organelles such as mitochondria

Question 15

A researcher is studying a pathogenic bacterium that uses endospores to survive harsh conditions. Which of the following genera is most likely being studied?

Accepted Answer

Bacillus

Question 16

Which of the following best explains why prions are unique infectious agents?

Accepted Answer

They are composed only of protein and lack nucleic acids.

Question 17

A patient presents with a disease caused by a pathogenic bacterium. Which of the following is NOT a typical method by which bacteria cause disease in humans?

Accepted Answer

By integrating their DNA into the host genome and producing viral particles

Question 18

Which of the following best describes the difference between lytic and lysogenic viral replication cycles?

Accepted Answer

The lytic cycle results in immediate destruction of the host cell, while the lysogenic cycle involves integration of viral DNA into the host genome without immediate lysis.

Question 19

Which of the following is a key characteristic used to classify viruses into families?

Accepted Answer

Type of nucleic acid (DNA or RNA), capsid symmetry, and presence or absence of an envelope

Question 20

A laboratory technician is asked to culture viruses in the lab. Which of the following is the most appropriate method for culturing animal viruses?

Accepted Answer

Inoculating susceptible living cells or cell cultures

Microbiology Study Guide: Key Concepts and Structures (Chapters 3, 11, 13, 24, 25)

Study Guide - Practice Questions

Study Guide - Flashcards