Question

What is the morphology of viruses?

Answer 1

Virus:

1. A virus is the smallest infective agent.
2. They do not possess any cellular organization and hence they are acellular
3. This means they lack most of the cell components like organelles, plasma membrane, ribosomes, etc.
4. Hence they may usage of the host machinery in order to replicate.
5. They contain only one type of nucleic acid - either DNA or RNA.
6. The complete infectious particle of the virus is called - virion.
7. The virion contains a nucleic acid core and an outer protein coating called- capsid.
8. Some viruses also contain an outer envelope made of proteins and phospholipids.
9. The capsid is composed of a large number of protein subunits called capsomeres.
10. The capsid with the nucleic acid core is known as the nucleocapsid.
11. The capsid protects the virus from destruction and provides a binding site to attach to the host.
12. A virus comes in many shapes and sizes.
13. The shape of viruses can be classified into 4 groups- icosahedral, filamentous, enveloped, and head-tail.

Examples: Adenovirus, Myxovirus, Coronavirus, Polumyxovirus, Lyssavirus.