Question 1

Which of the following statements best explains why viruses are not considered living cells?

Accepted Answer

Viruses lack cellular structure and cannot carry out metabolism independently.

Question 2

A scientist is studying a virus that has a rod-shaped capsid and infects plants. Which viral morphology does this virus most likely exhibit?

Accepted Answer

Helical

Question 3

Which of the following is TRUE regarding the replication of DNA viruses?

Accepted Answer

DNA viruses use host enzymes in the nucleus for transcription and translation.

Question 4

A virus is found to have glycoprotein spikes on its surface. What is the primary function of these spikes?

Accepted Answer

To attach to host cell receptors and facilitate entry

Question 5

Which step in the viral replication cycle involves the removal of the capsid to release viral nucleic acid into the host cell cytoplasm?

Accepted Answer

Uncoating

Question 6

A patient is diagnosed with shingles, which is caused by reactivation of the varicella-zoster virus. What type of viral infection does this represent?

Accepted Answer

Latent infection

Question 7

Which of the following viruses is most likely to carry reverse transcriptase as part of its replication process?

Accepted Answer

Retrovirus

Question 8

A researcher observes that a virus can pass through a filter with pore size $$0.22\ \mu m$$ that retains bacteria. What does this property indicate about the virus?

Accepted Answer

It is a filterable agent

Question 9

Which of the following is NOT a criterion used for the classification of viruses?

Accepted Answer

Biochemical tests

Question 10

A virus infects a host cell and buds off from the host membrane, acquiring a lipid envelope. What type of virus is this?

Accepted Answer

Enveloped virus

Question 11

Which of the following best describes the role of a capsid in a virus?

Accepted Answer

It surrounds and protects the viral genetic material

Question 12

A virus is found to cause transformation of host cells, leading to tumor formation. Which term best describes this virus?

Accepted Answer

Oncogenic virus

Question 13

Which of the following statements about prions is correct?

Accepted Answer

Prions are infectious proteins without nucleic acid.

Question 14

Which laboratory method is commonly used to quantify viruses by counting clear zones formed on a cell layer?

Accepted Answer

Plaque assay

Question 15

A virus with a positive-sense single-stranded RNA genome ($$+ssRNA) $$infects a cell. What is the first step in its replication?

Accepted Answer

Translation of viral proteins directly from the RNA

Question 16

Which of the following best explains why antibiotics are ineffective against viruses?

Accepted Answer

Viruses lack the cellular structures targeted by antibiotics.

Question 17

A non-enveloped virus is released from a host cell. What is the most likely mechanism of release?

Accepted Answer

Cell lysis

Question 18

Which of the following is a function of viral glycoprotein spikes that contributes to antigenic variation in influenza viruses?

Accepted Answer

They mutate, leading to changes in viral surface antigens.

Question 19

A scientist is working with a virus that infects bacteria and has a complex morphology with a tail structure. What is this type of virus called?

Accepted Answer

Bacteriophage

Question 20

Which of the following best describes the process of lysogeny in bacteriophage replication?

Accepted Answer

The phage integrates its genome into the host DNA and remains dormant.

Comprehensive Study Notes: Viruses (Chapter 13) – Structure, Classification, Replication, and Infection

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