Question

Capsid is
A. Genetic material of virus
B. Protein cover of virus
C. Extra genetic material of bacteria
D. Housekeeping genome of bacteria

Answer 1

Hint: Capsid is basically a shell (cover) or an outer layer present in certain organisms. They are present in place of the cell wall and they protect the genome from nucleases.

Complete answer:
Viruses are microscopic, non cellular, infectious agents which are present in inactive states outside a host and they become active once they enter a host. Therefore, they can neither be classified as living or non-living organisms.
They are generally small in size and range between 30 to 50nm and they lack a cell wall but have a capsid around them. Capsid is a coiled structure made up of proteins that holds nucleic acid of a virus.

Capsids are classified as per their structure. Many of the viruses have capsids with helical (spiral) or icosahedral (polyhedron with 20 faces). The proteins that help in making of capsid are known as capsid proteins or viral coat proteins (vcp). Also capsid and inner genetic material (genome) is known as nucleocapsid. So, the correct answer is capsid is a protein cover of a virus. Capsid are broadly classified according to their shape (structure).
Therefore, from the above explanation the correct option is (B) Protein cover of virus.

Note: Various properties of viruses are,
i) They have a protein coat around them known as capsid and their core is made up of DNA or RNA but never both
ii) They have spikes which helps in attachment to the host cell
iii) They do not grow, metabolise or respire but they can reproduce