Question 1

Which of the following best describes a virus?

Accepted Answer

An infectious particle consisting of genetic material (DNA or RNA) enclosed in a protein coat, unable to reproduce or carry out metabolism outside a host cell

Question 2

What is the primary function of a viral capsid?

Accepted Answer

It is the protein shell, built from capsomeres, that encloses the viral genome

Question 3

Which of the following statements about viral genomes is correct?

Accepted Answer

Viral genomes may consist of either double- or single-stranded DNA or RNA

Question 4

How does the lysogenic cycle differ from the lytic cycle in phage reproduction?

Accepted Answer

In the lysogenic cycle, viral DNA integrates into the host chromosome as a prophage and is replicated along with the host without killing it, while the lytic cycle culminates in host cell death

Question 5

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

Accepted Answer

Antibiotics target bacterial structures/processes that viruses do not have, since viruses are not cells

Question 6

What makes retroviruses like HIV unique in how they use their genetic material?

Accepted Answer

They use reverse transcriptase to copy their RNA genome into DNA, which then integrates into the host genome

Question 7

How does the bacterial CRISPR-Cas system provide immunity against phage infection?

Accepted Answer

It stores DNA fragments from previous phage infections between repeat sequences, allowing the bacterium to recognize and cut up matching phage DNA on reinfection

Question 8

Which of the following is cited as a major cause of emerging viral diseases in humans?

Accepted Answer

Viruses spreading from other animal species into humans

Question 9

Plant viruses spread via horizontal and vertical transmission. What does horizontal transmission refer to?

Accepted Answer

Entering the plant through damaged cell walls

Question 10

Prions are unusual infectious agents because they:

Accepted Answer

Are misfolded proteins that can convert normal proteins into the same misfolded, disease-causing form

Question 11

A scientist discovers a new virus with a genome consisting of a single linear molecule of RNA, surrounded by a protein coat and a membranous envelope. Which of the following features would most likely be present in this virus?

Accepted Answer

Viral glycoproteins on the envelope that bind to specific host cell receptors

Question 12

Which of the following best describes the role of restriction enzymes in bacterial defense against phages?

Accepted Answer

They cut up foreign DNA, such as phage DNA, preventing infection

Question 13

A temperate phage infects a bacterium and integrates its DNA into the host genome. What is this integrated viral DNA called?

Accepted Answer

Prophage

Question 14

Which of the following is a correct statement about the evolution of viruses?

Accepted Answer

Viruses likely evolved as bits of cellular nucleic acid, possibly from plasmids or transposons

Question 15

Which of the following is a real-world example of a pandemic caused by an emerging virus?

Accepted Answer

The 2009 H1N1 influenza outbreak

Question 16

Which of the following best explains why the H5N1 influenza strain is considered highly dangerous but has not caused a pandemic?

Accepted Answer

It is not transmitted from person to person

Question 17

Which of the following statements about vaccines is correct?

Accepted Answer

Vaccines are derivatives of pathogens that stimulate the immune system to mount defenses against the harmful pathogen

Question 18

A patient is diagnosed with a degenerative brain disease caused by prions. Which of the following best describes the mechanism of prion propagation?

Accepted Answer

Prions convert normal proteins into the misfolded, disease-causing form, which then aggregate

Question 19

Which of the following is a key difference between a provirus and a prophage?

Accepted Answer

A provirus is the permanently integrated retroviral DNA in a host's genome, unlike a prophage which can excise itself and re-enter a lytic cycle

Question 20

Which of the following equations best represents the exponential growth of a virus population in a permissive host, assuming each virus produces $$n$$ new viruses per replication cycle and there are $$t$$ cycles?

Accepted Answer

$$N = n^t$$

Viruses: Structure, Replication, and Pathogenicity (Campbell Biology, Ch. 19)

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드