250+ TOP MCQs on Classification of Viruses and Answers

Virology Multiple Choice Questions on “Classification of Viruses”.

1. Which of the following has responsibility for the assignment of new viruses to specific groupings?
a) ICC
b) ICTV
c) ITC
d) RCM

Answer: b
Clarification: The International Committee on Taxonomy of Viruses has responsibility for the assignment of new viruses to specific groupings. It authorizes the nomenclature and taxonomic classification of viruses.

2. Which of the following virus causes shingles when it is reactivated?
a) Varicella zoster
b) Adenovirus
c) HPV
d) Aichi virus

Answer: a
Clarification: Varicella zoster virus is a virus that causes shingles when it is reactivated. In the first infection, it causes chickenpox and when it gets reactivated, it causes shingles. Shingles cause a painful rash and can occur anywhere on the body.

3. Which of the following viruses are icosahedrons?
a) Filamentous virus
b) Complex virus
c) Simple virus
d) Isometric virus

Answer: d
Clarification: Isometric viruses are the viruses that are approximately spherical but are icosahedrons or icosadeltahedrons. Filamentous viruses have simple and helical morphology whereas complex viruses are made up of a combination of isometric and filamentous components.

4. The Baltimore classification was based on the importance of ____________
a) DNA
b) mRNA
c) rRNA
d) tRNA

Answer: b
Clarification: The original Baltimore classification scheme was based on the importance of messenger RNA or mRNA in the replication cycle of viruses. The viruses do not contain elements or molecules which are necessary to translate mRNA and rely on host cells to provide these elements.

5. Which of the following class contains all viruses that have dsDNA genomes?
a) Class I
b) Class II
c) Class III
d) Class IV

Answer: a
Clarification: Class I of the Baltimore classification scheme contains all the viruses that have double-stranded DNA (dsDNA) genomes. The designation of positive and negative sense is not meaningful in this case, since mRNAs may come from either strand.

6. Class III of Baltimore classification contains viruses with __________
a) dsDNA
b) dsRNA
c) ssRNA
d) ssDNA

Answer: b
Clarification: Class III of the Baltimore classification scheme contains all the viruses that have double-stranded RNA (dsRNA) genomes. Here, mRNA is only synthesized from one template strand of each segment.

7. Which of the following class consists of ambisense viruses?
a) Class 5
b) Class 7
c) Class 2
d) Class 4

Answer: a
Clarification: Some of the class 5 viruses use the newly synthesized antigenome RNA strand as a template for the production of an mRNA and are referred to as ambisense viruses. Class 5 contains viruses that have ssRNA genomes that are complementary to mRNA.

8. In which year was ICTV established?
a) 1960
b) 1965
c) 1963
d) 1966

Answer: d
Clarification: The International Committee on Taxonomy of Viruses (ICTV) was established in 1966 as the International Committee on Nomenclature of Viruses, but the name was later renamed to ICTV. It is governed by Statutes approved by the Virology division.

9. Measles virus belong to the family ______________
a) Paramoxyviridae
b) Filoviridae
c) Bunyaviridae
d) Flaviviridae

Answer: a
Clarification: Measles virus belongs to the family Paramoxyviridae in order of Mononegavirales and currently 49 species are placed under this family, divided among seven genera.

10. Satellite viruses do not encode enzymes for replication.
a) True
b) False

Answer: a
Clarification: Neither satellite viruses nor satellite nucleic acids encode for the enzymes that are required for the replication of their genomes. They require helper viruses to provide replicative enzymes.

11. Viruses are larger than prions.
a) True
b) False

Answer: a
Clarification: Viruses are larger than prions. Prions are very smaller than viruses and even smaller than the smallest of the viruses and can be seen only through the electron microscope.

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