NEET BIOLOGY

Detailed explanation-1: -The viral attachment protein can be viewed as the “key” that unlocks the cells by interacting with the “lock”-the receptor-on the host-cell surface, initiating critical downstream steps in the viral life cycle.

Detailed explanation-2: -The main functions of viral capsids are to protect, transport and deliver their genome.

Detailed explanation-3: -These proteins mediate two essential functions: attachment of the virion to the cell surface; and fusion of the viral envelope with a cell membrane, resulting in accession of the viral nucleocapsid containing the genome to the cellular cytoplasm. The membrane is acquired during viral assembly within an infected cell.

Detailed explanation-4: -Prior to entry, a virus must attach to a host cell. Attachment is achieved when specific proteins on the viral capsid or viral envelope bind to specific proteins called receptor proteins on the cell membrane of the target cell.

Detailed explanation-5: -The essential functions of the capsid are to protect the functional integrity of the viral RNA when the virion is outside the host cell and to initiate the infectious process when a receptor on a suitable host cell is encountered.