Target: 10 questions in 10 minutes
1. Which of the following is a structural feature common to all viruses?
  • A. A cell wall made of peptidoglycan
  • B. A capsid made of protein
  • C. DNA
  • D. Ribosomes for protein synthesis

2. The image below is an electron micrograph of a lambda bacteriophage virus:

 ViralZone, SIB Swiss Institute of Bioinformatics: Siphoviridae. Photographer: Hans-Wolfgang Ackermann
CC BY 4.0
What is the approximate actual size of the sheath in real life?
  • A. 1500nm
  • B. 150μm
  • C. 0.15mm
  • D. 0.15μm
3. Which of the following applies with regards to the origins of viruses?
  • A. All viruses have similar genetic codes indicating divergent evolution
  • B. The fact they share obligate parasitism suggest convergent evolution
  • C. Viruses do not share their genetic code with living organisms so evolved entirely separately
  • D. Viruses use identical enzymes for replication as their host organisms suggesting they a common ancestor

4. Why do influenza viruses exhibit rapid rates of evolution?

  • A. They undergo rapid meiosis
  • B. They have large genomes that are highly stable
  • C. They have high mutation rates and can recombine genetic material
  • D. They do not rely on host cells for replication
5. Why does HIV exhibit a rapid rate of evolution?
  • A. Low viral loads (population) in infected individuals
  • B. DNA polymerase has proofreading mechanisms
  • C. Errors in conversion of viral DNA to viral RNA
  • D. Reverse transcriptase lacks proofreading mechanisms

6. Which of the following applies to bacteriophage viruses?

I. The lytic cycle involves immediate replication and release of viral progeny.
II. The lysogenic cycle involves integration of viral DNA into the host genome.
III. Both the lytic and lysogenic cycles lead to rapid host cell death.
IV. The lysogenic cycle allows the viral DNA to remain dormant within the host cell.
  • A. I and III only
  • B. IV only
  • C. I, II, and IV only
  • D. I, II, III only
Q7&8. The image shows the interaction of a bacteriophage with a host cell:

Bruna Espiño dos Santos
CC BY 4.0
7. Which stage best shows that specific bacteriophages only infect specific bacteria?
8. Which stage shows lysis?
9. Which of the following is an example of a non-enveloped virus?
  • A. Lambda bacteriophages
  • B. Coronaviruses
  • C. HIV
  • D. Influenza viruses

10. Which of the following applies in the context of viruses?

I. Enveloped viruses have an advantage over non-enveloped viruses in evading the host immune system.
II. Envelopes facilitate the attachment of viruses to host cells.
III. Envelopes protect the viral genetic material from degradation.
  • A. I only
  • B.  I and II only
  • C.  II and III only
  • D. I, II, and III