structure and shape of virus

Structure and shape of virus

Each virus has characteristic structure.

For example; 

Rabies virus has bullet shape

Polio virus has round and spherical shape

Virion consist of nucleic acid, which is surrounded by protein coat called capsid.

Capsid encloses a nucleic acid and called nucleic capsid.

Function of capsid

1. Protect nucleic acid from harmful environment

2. Help virus to stick/ penetration to host cell

3. Capsid composed of small unit of protein called capsomere.

4.Help to introduce vir DNA /RNA into suitable host cell.

5. Stimulate the immune system to produce antibodies that can protect the host cell against future Infections.

Type of Capsid

Different types of arrangement of capsid in different types of virus;

1. Helical arrangement

When nucleic acid is coiled, arrangement called helical arrangement.

2. Cubical arrangement

When spherical nucleic acid surrounds by cube called cubical arrangement.

3. Complex arrangement

For example; Bacteriophage pox virus