1. Which of the following virus have virions with internal lipid membranes?
a) Rabies virus
b) Influenza virus
c) Ebola virus
d) Iridovirus
Explanation: Iridoviruses are viruses that have a lipid membrane within the virion rather than at the surface. Other examples include tectiviruses and chlorella virus. Rabies, Influenza, and Ebola viruses have lipid membranes at the surface of the virion.
2. The viral envelope is made up of protein bilayer.
a) True
b) False
Explanation: The viral envelope is made up of the lipid component, which is present at the surface of virion or present within the virion. It protects the capsid and may help viruses avoid the host immune system.
3. The viral genome contains non-repeated sequences.
a) True
b) False
Explanation: The genome of viruses contains several repeated sequences which include promoters, enhancers, the origin of replication, and other important elements that are involved in the control of events in the replication of the virus.
4. Which of the following has responsibility for the assignment of new viruses to specific groupings?
a) ICC
b) ICTV
c) ITC
d) RCM
Explanation: 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.
5. Which of the following virus causes shingles when it is reactivated?
a) Varicella zoster
b) Adenovirus
c) HPV
d) Aichi virus
Explanation: 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.
6. Which of the following viruses are icosahedrons?
a) Filamentous virus
b) Complex virus
c) Simple virus
d) Isometric virus
Explanation: 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.
7. The Baltimore classification was based on the importance of ____________
a) DNA
b) mRNA
c) rRNA
d) tRNA
Explanation: 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.
8. Which of the following class contains all viruses that have dsDNA genomes?
a) Class I
b) Class II
c) Class III
d) Class IV
Explanation: 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.
9. Class III of Baltimore classification contains viruses with __________
a) dsDNA
b) dsRNA
c) ssRNA
d) ssDNA
Explanation: 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.
10. Which of the following class consists of ambisense viruses?
a) Class 5
b) Class 7
c) Class 2
d) Class 4
Explanation: 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.