1. Which of the following is a basic structural component of a virus?
a) Nucleus
b) Ribosomes
c) Capsid
d) Mitochondria
Answer: c) Capsid
2. The genetic material of a virus is composed of:
a) DNA or RNA
b) Proteins only
c) Carbohydrates and lipids
d) Nucleotides only
Answer: a) DNA or RNA
3. What type of nucleic acid can be found in viruses?
a) DNA
b) RNA
c) Both DNA and RNA
d) Neither DNA nor RNA
Answer: c) Both DNA and RNA
4. What is the function of the viral capsid?
a) Protects the viral genome
b) Synthesizes proteins
c) Helps in cellular respiration
d) Converts RNA to DNA
Answer: a) Protects the viral genome
5. A virus that infects bacteria is called a:
a) Viroid
b) Bacteriophage
c) Retrovirus
d) Prion
Answer: b) Bacteriophage
6. Which part of the virus is responsible for attaching to the host cell?
a) Envelope
b) Capsid
c) Tail fibers (in bacteriophages)
d) RNA or DNA
Answer: c) Tail fibers (in bacteriophages)
7. Which of the following is a characteristic of the viral life cycle?
a) Independent reproduction
b) Replication inside a host cell
c) Energy production by itself
d) Continuous division
Answer: b) Replication inside a host cell
8. The process of a virus entering a host cell is called:
a) Replication
b) Absorption
c) Penetration
d) Translation
Answer: c) Penetration
9. In which step of the viral life cycle does the virus release new viral particles?
a) Attachment
b) Replication
c) Assembly
d) Release
Answer: d) Release
10. The term “lytic cycle” refers to:
a) A viral life cycle where the virus remains dormant
b) A viral life cycle where new virions are formed and released
c) The production of bacterial cells
d) A cycle of protein synthesis in bacteria
Answer: b) A viral life cycle where new virions are formed and released
11. Which viral structure is involved in the entry of the virus into the host cell?
a) Capsid
b) Envelope
c) Genome
d) Tail sheath
Answer: b) Envelope
12. Which of the following viruses replicate their RNA genome into DNA inside a host cell?
a) Retroviruses
b) Adenoviruses
c) Herpesviruses
d) Bacteriophages
Answer: a) Retroviruses
13. What is a key difference between the lytic and lysogenic cycles?
a) Lysogenic cycle involves the destruction of the host cell
b) In lytic cycle, viral genome integrates into the host genome
c) In lysogenic cycle, the virus stays dormant for a while
d) Lytic cycle involves viral integration into the host genome
Answer: c) In lysogenic cycle, the virus stays dormant for a while
14. What is the main difference between DNA and RNA viruses?
a) DNA viruses have larger genomes
b) RNA viruses replicate in the nucleus
c) DNA viruses always cause diseases
d) RNA viruses replicate in the cytoplasm
Answer: d) RNA viruses replicate in the cytoplasm
15. Which of the following is a viral protein that can integrate into the host genome?
a) Protease
b) Reverse transcriptase
c) Capsid protein
d) Polymerase
Answer: b) Reverse transcriptase
16. Which of the following best describes the viral envelope?
a) A protein shell that protects the viral genome
b) A lipid bilayer derived from the host cell membrane
c) A carbohydrate layer that attaches to host cells
d) A layer of protein and nucleic acid
Answer: b) A lipid bilayer derived from the host cell membrane
17. Which of the following viruses is responsible for causing the flu?
a) Hepatitis virus
b) Influenza virus
c) Herpesvirus
d) HIV
Answer: b) Influenza virus
18. Which term refers to the attachment site on the host cell surface for a virus?
a) Receptor
b) Antigen
c) Antibody
d) Cytokine
Answer: a) Receptor
19. In the viral life cycle, what happens after the viral genome is released into the host cell?
a) The virus exits the host cell
b) The host cell divides into two
c) The viral genome is replicated and transcribed
d) The virus destroys the host cell immediately
Answer: c) The viral genome is replicated and transcribed
20. What is a characteristic feature of retroviruses?
a) They replicate their RNA into DNA
b) They are DNA viruses
c) They replicate using only RNA
d) They lack an envelope
Answer: a) They replicate their RNA into DNA
21. Which type of virus contains a double-stranded DNA genome?
a) HIV
b) Influenza virus
c) Herpesvirus
d) Hepatitis C virus
Answer: c) Herpesvirus
22. What is the role of viral enzymes like proteases and reverse transcriptase?
a) To build viral proteins
b) To degrade host cell proteins
c) To break down the viral genome
d) To help in viral replication
Answer: d) To help in viral replication
23. Which structure in a virus helps the virus to penetrate host cells?
a) Ribosome
b) Tail fibers
c) Nucleus
d) Chloroplast
Answer: b) Tail fibers
24. Which of the following is a feature of the lysogenic cycle?
a) New viral particles are immediately assembled
b) The virus integrates its genome into the host DNA
c) The host cell is destroyed quickly
d) Viral particles are released without cell damage
Answer: b) The virus integrates its genome into the host DNA
25. What does a “virus host range” refer to?
a) The number of viruses that infect a host
b) The range of hosts a virus can infect
c) The period a virus can survive outside a host
d) The viral lifecycle stage in which infection occurs
Answer: b) The range of hosts a virus can infect
26. In which phase of the viral life cycle does the host cell burst, releasing new viral particles?
a) Assembly
b) Release
c) Replication
d) Attachment
Answer: b) Release
27. What determines the specificity of a virus to infect certain host cells?
a) The viral genome size
b) The virus’s nucleic acid structure
c) The interaction between viral proteins and host receptors
d) The viral capsid shape
Answer: c) The interaction between viral proteins and host receptors
28. What type of virus is known for causing cancer in infected cells?
a) Retrovirus
b) Bacteriophage
c) Adenovirus
d) Papillomavirus
Answer: a) Retrovirus
29. Which process occurs during the assembly phase of the viral life cycle?
a) The viral genome is transcribed into RNA
b) Viral proteins and genomes are packaged into new virions
c) The host cell’s DNA is replicated
d) The virus releases viral particles into the environment
Answer: b) Viral proteins and genomes are packaged into new virions
30. Which virus is responsible for the common cold?
a) Herpes simplex virus
b) Rhinovirus
c) Hepatitis B virus
d) Epstein-Barr virus
Answer: b) Rhinovirus
