Virus Structure and Classification

Question 1

What is a virus?

Answer 1

Question 2

What is a virion?

Answer 2

a complete virus particle is called a virion (virion size varies from 20–300 nm)

Question 3

Types of Viruses

Answer 3

Question 4

Prions

Answer 4

Prions are protein molecules without genes, which become infectious due to conformational changes in the prion protein. They are responsible for some neurologic disorders such as Kuru, CJD, mad-cow disease (discussed in persistent viral infection of the CNS).

Question 5

Viroids

Answer 5

Viriods are infectious circular RNA molecules without a protein shell. They are responsible for plant disorders (this information is for educational purpose).

Question 6

5 Types of Viral Infection

Answer 6

Question 7

Answer 7

Question 8

Virus Genome

Answer 8

DNA or RNA

Question 9

RNA Viruses

Answer 9

Question 10

DNA Viruses

Answer 10

Question 11

Capsid

Answer 11

• protein shell
• naked capsid
• nucleocapsid

Question 12

Envelope

Answer 12

• mainly derived from cellular membranes
• lipid bilayer

Question 14

Naked Capsid Viruses

Answer 14

Question 15

Enveloped Viruses

Answer 15

• Derived from host cell plasma or nuclear membranes
• Lipid bilayer membrane containing virus specific proteins and/or glycoproteins called spikes or peplomers
• Envelope proteins bind to receptors on the host cell
• Help in fusion with the cell membrane
• Elicit immune responses, both humoral and cell mediated

Question 16

Protein (Capsid) Architecture

Answer 16

Question 17

Classification of Viruses

Answer 17

Question 18

Virus Family

Answer 18

Designated with suffix - viridae

•Herpesviridae

Question 19

Virus Subfamilies

Answer 19

Designated with suffix - virinae

•Herpesvirinae

Question 20

Virus Genera

Answer 20

Designated - with suffix virus

•Herpesvirus

Question 21

Virus Species

Answer 21

Designated with with virus

•Herpes simplex virus 2