Question 1

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

Accepted Answer

Capsid, nucleic acid, envelope, and spikes

Question 2

Viruses are measured in which unit, and what is the equivalent of 1 nanometer in meters?

Accepted Answer

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

Question 3

Which of the following is NOT a characteristic of viruses?

Accepted Answer

They metabolize nutrients independently

Question 4

Which viral shape is correctly matched with an example?

Accepted Answer

Helical - Rabies virus

Question 5

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

Accepted Answer

Lytic cycle results in immediate host cell lysis, while lysogeny integrates viral DNA into the host genome

Question 6

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

Accepted Answer

Dmitri Ivanovsky

Question 7

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

Accepted Answer

A 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 of the following diseases is NOT caused by a virus?

Accepted Answer

Tuberculosis

Question 10

What is the function of viral spikes (glycoproteins) found on the envelope?

Accepted Answer

Attachment and entry into host cells

Question 11

Which statement about bacteriophages used in food safety (e.g., LISTEX P100) is correct?

Accepted Answer

They specifically target harmful bacteria without affecting humans or desirable bacteria

Question 12

Which of the following is a correct description of a viroid?

Accepted Answer

A small, circular RNA molecule that infects plants

Question 13

Prions are associated with which disease?

Accepted Answer

Creutzfeldt-Jakob disease

Question 14

Which of the following is a beneficial role of viruses in natural ecosystems?

Accepted Answer

Regulation of microbial populations

Question 15

Which step in the lytic cycle involves the assembly of new viral particles?

Accepted Answer

Maturation

Question 16

A virus with a capsid composed of 20 triangular faces and 12 corners is classified as:

Accepted Answer

Icosahedral (polyhedral)

Question 17

Which of the following statements about viral host specificity is correct?

Accepted Answer

Viruses recognize host cells by matching their surface antigens to host cell receptors

Question 18

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

Accepted Answer

Growing on nutrient agar plates

Question 19

Which influenza subtype was responsible for the 1918 Spanish flu pandemic?

Accepted Answer

H1N1

Question 20

Which of the following equations correctly represents the conversion from nanometers to meters?

Accepted Answer

$$1 	ext{ nm} = 10$$^{-9}$$ 	ext{ m}$$

Viruses: Structure, Classification, and Roles in Microbiology

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