Question

Given below is a diagram of a T-4 bacteriophage. Choose the option that has all the parts correctly labelled.

• A. A-Head, B-Sheath, C-Collar, D-Tail fibres
• B. A-Sheath, B-Head, C-Collar, D-Tail fibres
• C. A-Head, B-Collar, C-Sheath, D-Tail fibres
• D. A-Collar, B-Head, C-Sheath, D-Tail fibres

Answer 1

The correct option is C A-Head, B-Collar, C-Sheath, D-Tail fibres

Bacteriophages are viruses that infect bacteria. The genetic material in them is usually double-stranded DNA. A typical bacteriophage, for example, the T-4 bacteriophage that infects E.coli. Their structure comprises of:

• A polyhedral head that consists of the nucleic acid surrounded by a protein coat or capsid.
• A collar present below the head that joins the head with the tail.
• A sheath that is contractile in nature and helps the viral genetic material to enter the host cell.
• The tail fibres are used to attach to the host cell.