Question

Explain replication of bacteriophage with the help of a suitable diagram.

Answer 1

the following steps:

1. Attachment: Bacteriophages attach to specific receptors on the surface of bacteria. As
   phages do not move independently, they rely on random encounters with the right
   receptors.
2.  Penetration: After attachment, the tail fibres bring the base plate closer to the surface
   of the cell. Once attached completely, the tail contracts, injecting genetic material
   (DNA) through the bacterial membrane. (Capsid – protein coat remains outside and is
   called ‘ghost’)
3. Degradation of host DNA: Once the viral DNA enters the host cell, the degradation of
   host DNA starts.
4.  Synthesis of proteins and nucleic acid: The host’s normal synthesis of proteins and
   nucleic acids is disrupted, and it is forced to manufacture viral DNA and proteins
   instead. These products are the parts of new virions within the cell or proteins involved
   in cell lysis.
5.  Virion assembly: The base plates are assembled with the tails first. The head (capsids)
   are constructed separately and then are joined with the tails. The DNA is packed
   efficiently within the head. The whole process takes about 15 minutes.
6.  Release of virions: Phages are released via. lysis of cell. It is achieved by an enzyme
   called endolysin, which breaks down the cell wall. Released virions are capable of
   infecting a new bacterium.