Free Viruses MCQs with Answers
247 Viruses MCQs from Biology, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Viruses are acellular infectious particles made of genetic material enclosed by a protein capsid, sometimes with a lipid envelope. Their replication depends on a host cell and may follow lytic or lysogenic cycles, so viral structure and reproduction differ fundamentally from those of cellular organisms such as bacteria.
Last updated
247 questions · page 4 of 13
- A. Liver of man
- B. RBC of man
- C. Stomach wall of mosquito
- D. Salivary glands of mosquito
Explanation: Sporogony is the sexual stage of Plasmodium and occurs in the female Anopheles mosquito, mainly in its stomach wall after fertilisation.
Correct answer: Stomach wall of mosquito- A. Pasteur
- B. Chamberland
- C. Stanely
- D. Ivanowski
Explanation: Wendell M. Stanley crystallized tobacco mosaic virus in 1935, demonstrating that viruses could behave like chemical substances outside…
Correct answer: Stanely- A. sporozoites
- B. merozoites
- C. zygote
- D. none of these
Explanation: The female Anopheles mosquito injects Plasmodium sporozoites into human blood during a bite, and these first travel to liver cells.
Correct answer: sporozoites- A. bacteria
- B. protist
- C. virus
- D. fungi
Explanation: Influenza is caused by influenza viruses, which are enveloped RNA viruses that infect the respiratory tract.
Correct answer: virus- A. Replicated
- B. Turn off by the protein coat.
- C. Digested into its nucleotides
- D. Turned on by the removal of the protein coat
Explanation: During the lytic cycle, bacteriophage nucleases break the host bacterial DNA into nucleotides, which can then be reused for making viral…
Correct answer: Digested into its nucleotides- A. Influenza virus
- B. Herpes virus
- C. HBV
- D. Pox virus
Explanation: Influenza virus contains RNA as its genetic material, specifically segmented single-stranded RNA.
Correct answer: Influenza virus- A. Prophage
- B. Capsid
- C. Viron
- D. Retrovirus
Explanation: A temperate phage can integrate its DNA into the bacterial chromosome, where it is called a prophage.
Correct answer: Prophage- A. Joins the bacterial chromosomes
- B. Attaches to the inner surface of the host membrane
- C. Is immediately degraded when enters the host
- D. Goes directly to host ribosomes for translation
Explanation: In the lysogenic cycle, bacteriophage DNA becomes integrated into the bacterial chromosome and is replicated with the host DNA as a…
Correct answer: Joins the bacterial chromosomes- A. Spherical
- B. Rod Shaped
- C. Tadpole like
- D. Hexagonal
Explanation: Tobacco mosaic virus has a rigid helical capsid that gives the virion a characteristic rod-shaped form.
Correct answer: Rod Shaped- A. Absorption
- B. Multiplication
- C. Lysogeny
- D. Penetration
Explanation: After a phage attaches, or adsorbs, to receptors on the bacterial cell wall, it injects its nucleic acid into the host during penetration.
Correct answer: Penetration- A. Measles
- B. Herpes simplex
- C. Hepatitis
- D. Polio
Explanation: Poliovirus attacks motor neurons in the central nervous system and can cause paralysis.
Correct answer: Polio- A. Lysis
- B. Lysogeny
- C. Induction
- D. Adsorption
Explanation: Induction is the excision of prophage DNA from the bacterial chromosome followed by entry into the lytic cycle, often after environmental…
Correct answer: Induction- A. DNAase
- B. RNAase
- C. DNA polymerase
- D. Reverse Transcriptase
Explanation: Reverse transcriptase uses an RNA template to synthesize complementary DNA and can ultimately produce double-stranded viral DNA.
Correct answer: Reverse Transcriptase- A. Phage when gets incorporated with the bacterial chromosome is called prophage
- B. The bacterium continues to live and reproduce normally
- C. Lysogenic bacteria may get infected by the related phage
- D. The cycle may convert into lytic type resulting from environmental exposure
Explanation: A lysogenic bacterium containing a prophage is generally immune to superinfection by the same or a closely related phage because prophage…
Correct answer: Lysogenic bacteria may get infected by the related phage- A. Hepatitis virus
- B. Retrovirus
- C. Polio virus
- D. Pox virus
Explanation: Retroviruses have a strong association with tumour formation because some carry oncogenes or can activate host genes after integrating…
Correct answer: Retrovirus- A. Bacteria
- B. Cowpox Virus
- C. Adenovirus
- D. Prion
Explanation: Mad cow disease, or bovine spongiform encephalopathy, is caused by a prion, an infectious misfolded protein lacking a conventional…
Correct answer: Prion- A. Hepatitis virus
- B. Retrovirus
- C. Polio virus
- D. Pox virus
Explanation: Among these options, poliovirus is the smallest, with a compact, non-enveloped capsid and a genome of roughly 7.5 kilobases.
Correct answer: Polio virus- A. Separates in to two inner parts
- B. Can not metabolize
- C. Rapidly looses its Genome chemical inert
- D. Is coated with an air tight shield
Explanation: An isolated virus cannot perform independent metabolism because it lacks cellular machinery such as ribosomes and metabolic enzymes.
Correct answer: Can not metabolize- A. M type
- B. N type
- C. T type
- D. S type
Explanation: The bacteriophages that infect Escherichia coli are classically called T phages, including T1 through T7.
Correct answer: T type- A. Strong covalent bond between virion and the receptor site.
- B. Week chemical unior between them
- C. Both A and B depending upon the phage
- D. None of these
Explanation: Phage attachment to a bacterial receptor is a specific, reversible interaction involving weak non-covalent forces rather than a strong…
Correct answer: Week chemical unior between them