Question 1

Which of the following statements best explains why antibiotics are ineffective against viral infections such as influenza?

Accepted Answer

Viruses are not composed of cells and lack the metabolic pathways targeted by antibiotics.

Question 2

A patient is diagnosed with a persistent viral infection. Which of the following viruses is most likely responsible for this type of infection?

Accepted Answer

HIV, which can remain in the host for years and continuously produce new viruses.

Question 3

Which of the following is NOT a recognized morphological type of virus?

Accepted Answer

Polymorphic

Question 4

A laboratory is attempting to culture animal viruses. Which of the following methods would NOT be appropriate for this purpose?

Accepted Answer

Using glucose broth as a growth medium

Question 5

The protein subunits that make up the capsid of a virus are called:

Accepted Answer

Capsomeres

Question 6

Which of the following best describes a viroid?

Accepted Answer

A naked, infectious piece of RNA without a protein coat

Question 7

A scientist is using the plaque method to study viruses. What is the primary application of this technique?

Accepted Answer

To grow and quantify bacteriophages by counting clear zones on a bacterial lawn

Question 8

Which enzyme is responsible for synthesizing complementary double-stranded DNA from a viral RNA template, a process essential for retrovirus replication?

Accepted Answer

Reverse transcriptase

Question 9

A patient develops a neurological disorder after receiving a transplant of nerve tissue. Which type of infectious agent is most likely responsible, and what is the disease mechanism?

Accepted Answer

A prion, which causes misfolding of normal proteins in the brain

Question 10

Which of the following is the correct use of the suffix '-viridae' in viral taxonomy?

Accepted Answer

It denotes virus family names.

Question 11

A researcher is using serological methods to identify an unknown virus. Which principle underlies this approach?

Accepted Answer

Detection of specific viral antigens or antibodies in a sample

Question 12

Which of the following is an example of a latent viral infection in humans?

Accepted Answer

Shingles, caused by reactivation of varicella-zoster virus

Question 13

Which of the following best describes the role of oncogenes in virus-induced cancer?

Accepted Answer

Oncogenes are segments of DNA that, when altered by viruses, can lead to uncontrolled cell division.

Question 14

A patient is diagnosed with sarcoma. Which tissue type is primarily affected in this form of cancer?

Accepted Answer

Connective tissue

Question 15

Which of the following is NOT an effect of transformation in cells infected by oncogenic viruses?

Accepted Answer

Cells lose their ability to divide.

Question 16

Approximately what percentage of human cancers are known to be virus-induced?

Accepted Answer

$$10\%$$

Question 17

Which of the following is a common method for culturing continuous cell lines, and what is a key characteristic of these lines?

Accepted Answer

They are sometimes called immortal cell lines because they can be maintained through many generations.

Question 18

Which of the following is NOT a known route of prion disease transmission?

Accepted Answer

Inhalation

Question 19

Scrapie, a disease found in sheep, is best classified as which type of disease and caused by what agent?

Accepted Answer

A neurological disease caused by a prion

Question 20

Viruses that specifically infect and lyse cancer cells are known as:

Accepted Answer

Oncolytic viruses

Microbiology Study Guide: Viruses, Viroids, and Prions

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