Virus Quiz
Questions: 16 · 10 minutes
1. A laboratory first converts viral RNA into complementary DNA and then amplifies a target sequence. Which method is being used?
Gram staining
Reverse-transcription PCR
Standard bacterial culture
Antibody neutralization testing
2. Some viruses can persist in host cells with little or no production of new particles and later become active again. What is this state called?
Conjugation
Translation
Binary fission
Latency
3. A patient has an illness caused by a virus. Why would an antibiotic that targets bacterial cell walls usually be ineffective against it?
Viruses prevent all medicines from entering infected tissues.
Antibiotics work only when the immune system has never seen a pathogen.
Viral genomes immediately destroy every antibiotic molecule.
Viruses do not have the bacterial cell-wall structures targeted by that drug.
4. Several people who handle the same animal species develop infections caused by a closely related virus previously found in those animals. Which explanation is most directly supported?
The virus arose because antibiotics transformed bacteria into viruses.
The affected people inherited identical viral genomes from their parents.
The virus reproduced independently in the surrounding air.
A zoonotic spillover transmitted the virus from animals to humans.
5. A virus can enter one cell type but not another because only the first cell displays a matching surface molecule. What does this illustrate?
Host-cell specificity based on receptor recognition
Independent viral metabolism
Binary fission
Antibiotic resistance
6. A researcher isolates a virus that specifically infects bacterial cells. What is this virus called?
A viroid
A bacteriophage
A protozoan
A plasmid
7. Two related viruses with segmented genomes infect the same cell, and new particles receive segments from both. What process has occurred?
Translation
Binary fission
Reassortment
Simple point mutation
8. What does reverse transcriptase do in the replication cycle of a retrovirus?
It translates viral proteins directly from DNA.
It cuts a host cell into new virus particles.
It synthesizes DNA using viral RNA as a template.
It copies bacterial cell walls around the virus.
9. Soap can inactivate many enveloped viruses. Which explanation best accounts for this effect?
Soap converts the viral genome from RNA into harmless DNA.
Soap disrupts the lipid envelope needed for an intact infectious particle.
Soap blocks the host cell from producing antibodies.
Soap forces the virus to reproduce outside a host cell.
10. Which basic combination is present in every complete virus particle?
A cell membrane surrounding cytoplasm
Ribosomes and enzymes for independent metabolism
Both DNA and RNA enclosed by a cell wall
A DNA or RNA genome enclosed in a protein capsid
11. A vaccine presents the immune system with a harmless form or component of a virus. What is its primary intended effect?
To prepare adaptive immune memory for a later encounter
To prevent the body from recognizing viral antigens
To replace all innate immune defenses permanently
To make host cells independent of their normal receptors
12. Over many replication cycles, a viral population accumulates small genetic changes caused by copying errors. Which process best describes this?
Binary fission
Lysogeny caused by bacterial division
Mutation and genetic drift within the viral population
Reassortment without coinfection
13. How can neutralizing antibodies directly reduce a virus's ability to infect cells?
By supplying ribosomes that destroy the viral capsid
By binding viral structures and blocking attachment or entry
By converting viral RNA into bacterial DNA
By causing viruses to divide outside host cells
14. Thorough handwashing can reduce transmission of some non-enveloped gastrointestinal viruses even when they resist alcohol-based sanitizer. Why?
Washing can physically loosen and remove virus particles from the hands.
Water changes their RNA into DNA.
Soap causes human cells to stop displaying all receptors.
Handwashing makes the viruses dependent on antibiotics.
15. In a bacteriophage experiment, infected cells burst and release many newly formed virus particles. Which replication pattern does this demonstrate?
The lytic cycle
Cellular meiosis
Bacterial conjugation
Viral latency without particle production
16. Which feature most clearly distinguishes viruses from organisms that can reproduce independently?
Viruses reproduce by dividing into two daughter cells.
Viruses contain no genetic information of any kind.
Viruses must use a host cell's machinery to produce new virus particles.
Viruses generate their own energy through metabolism.