Question 1

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

Accepted Answer

They cannot reproduce independently outside of a host cell.

Question 2

A scientist discovers a new virus with a phospholipid bilayer surrounding its capsid. Which of the following is most likely true about this virus?

Accepted Answer

It is an enveloped virus and may be more sensitive to detergents.

Question 3

During the lytic cycle, which of the following sequences correctly describes the order of events?

Accepted Answer

Attachment → Entry → Replication → Assembly → Release

Question 4

Which of the following statements best distinguishes the lysogenic cycle from the lytic cycle?

Accepted Answer

The lysogenic cycle involves integration of the viral genome into the host DNA, allowing the virus to remain dormant.

Question 5

A patient is diagnosed with HIV, a retrovirus. Which enzyme is crucial for HIV to integrate its genetic material into the host genome?

Accepted Answer

Reverse transcriptase, which synthesizes DNA from the viral RNA template.

Question 6

Which of the following best describes the genetic material found in viruses?

Accepted Answer

Viruses can have either DNA or RNA, but not both, as their genetic material.

Question 7

A new viral outbreak is traced to a population of bats and then spreads to humans. This is an example of:

Accepted Answer

Zoonotic transmission, where a virus jumps from animals to humans.

Question 8

Which of the following steps in viral replication is directly responsible for the synthesis of viral proteins?

Accepted Answer

Transcription and translation

Question 9

Why are vaccines effective in preventing viral infections?

Accepted Answer

They prime the immune system to recognize and respond to the virus upon exposure.

Question 10

Which of the following is an example of an emerging viral disease that has had a significant global impact in the 21st century?

Accepted Answer

SARS-CoV-2

Question 11

A virus is classified as positive-sense single-stranded RNA. What does this mean for its replication strategy?

Accepted Answer

Its RNA genome can be directly used as mRNA for protein synthesis.

Question 12

Which of the following best explains why antiviral drugs are often more difficult to develop than antibiotics?

Accepted Answer

Viruses use host cell machinery for replication, making it hard to target the virus without harming host cells.

Question 13

A patient contracts a viral infection through a mosquito bite. Which transmission route is this?

Accepted Answer

Vector-borne transmission via arthropod bite.

Question 14

Which of the following is a key ecological implication of the lysogenic cycle compared to the lytic cycle?

Accepted Answer

The lysogenic cycle allows viruses to persist in host populations without immediately killing hosts, potentially increasing viral spread.

Question 15

Which of the following best describes the function of a viral capsid?

Accepted Answer

It is a protein shell that encloses and protects the viral genetic material.

Question 16

A virus with a double-stranded DNA genome infects a host cell. Which of the following steps must occur for the virus to produce new virions?

Accepted Answer

Transcription of viral DNA to mRNA, followed by translation to produce viral proteins.

Question 17

Which of the following is a reason why retroviruses like HIV are difficult to cure?

Accepted Answer

They integrate their DNA into the host genome, allowing the virus to persist even when not actively replicating.

Question 18

Which of the following best explains why understanding viral ecology is important for preventing pandemics?

Accepted Answer

It helps identify how viruses emerge, spread, and adapt, allowing for better surveillance and control strategies.

Question 19

A new antiviral drug is designed to inhibit the assembly step of viral replication. Which of the following would most likely result from this drug's action?

Accepted Answer

New viral particles would not be properly formed, reducing the number of infectious virions released.

Question 20

Which of the following equations best represents the exponential growth of a virus population during the lytic cycle, assuming each infected cell releases $n$ new virions per cycle and $t$ cycles have occurred?

Accepted Answer

$N = N_0 	imes n^t$

Viruses: Structure, Replication, Ecology, and Human Health

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