Question 1

Which of the following best describes the four major components of a typical virus?

Accepted Answer

Capsid, nucleic acid, envelope, spikes

Question 2

Viruses are measured using which unit, and what is the conversion from meters to this unit?

Accepted Answer

Nanometers; $$1 nm = 10$$^{-9}$$ m$$

Question 3

Which of the following is NOT a characteristic of viruses?

Accepted Answer

Ability to metabolize nutrients independently

Question 4

Which viral shape is exemplified by the rabies and Ebola viruses?

Accepted Answer

Helical

Question 5

What is the main difference between the lytic cycle and lysogeny in bacteriophage replication?

Accepted Answer

Lytic cycle results in immediate destruction of the host cell, while lysogeny allows viral DNA to integrate into the host genome and remain dormant.

Question 6

Which scientist is credited with the discovery of the Tobacco mosaic virus in plants in 1892?

Accepted Answer

Dmitri Ivanovsky

Question 7

A bacteriophage that can undergo both the lytic and lysogenic cycles is called:

Accepted Answer

Temperate phage

Question 8

Which of the following best explains why viruses are considered non-living?

Accepted Answer

They cannot reproduce on their own and lack cellular structure.

Question 9

Which structure on the influenza virus is responsible for attachment and entry into host cells?

Accepted Answer

Spikes (glycoproteins)

Question 10

Which of the following diseases is caused by a prion?

Accepted Answer

Creutzfeldt-Jakob disease

Question 11

A viroid differs from a virus in that it:

Accepted Answer

Consists only of a short strand of circular RNA without a protein coat.

Question 12

Which of the following is a beneficial role of viruses in biotechnology?

Accepted Answer

Phages are used to lyse bacteria in food production, reducing spoilage.

Question 13

Which of the following best describes the host specificity of viruses?

Accepted Answer

Viruses recognize and infect only cells with matching surface receptors.

Question 14

Which of the following is a correct sequence of steps in the lytic cycle?

Accepted Answer

Attachment, penetration, biosynthesis, maturation, release

Question 15

Which viral shape is characterized by a 20-sided structure with 12 corners?

Accepted Answer

Polyhedral (Icosahedron)

Question 16

Which of the following viruses is an example of a complex-shaped virus?

Accepted Answer

Bacteriophage

Question 17

Which of the following statements about bacteriophages used in food safety (e.g., LISTEX P100) is correct?

Accepted Answer

They specifically target and lyse Listeria bacteria without harming humans, animals, or plants.

Question 18

Which of the following is NOT a method for culturing viruses?

Accepted Answer

Growing viruses on nutrient agar plates

Question 19

Which of the following viruses is enveloped and contains spikes for host cell attachment?

Accepted Answer

Influenza virus

Viruses: Structure, Classification, and Roles in Microbiology

Study Guide - Practice Questions