Question

What are the different phases of T4 bacteriophage cycle?

1) Adsorption
2) Penetration
3) Degradation of host's cells
4) Biosynthesis phase
5) Maturation phase
6) Release phase

Answer 1

The T4 bacteriophage cycle consists of six phases: adsorption, penetration, degradation, biosynthesis, maturation, and release, culminating in the lysis of the E. coli host cell and the spreading of newly formed virions.

Step-by-step explanation:

The T4 bacteriophage cycle involves a series of phases that ultimately lead to the production of new virions and the lysis of the host cell. During the adsorption phase, the T4 bacteriophage recognizes and attaches to specific receptors on the surface of the E. coli bacterium. Following this, the penetration phase occurs when the phage injects its DNA into the host cell, leaving its capsid outside.

The degradation phase involves the phage's viral genome manifesting virus-encoded endonucleases to degrade the bacterial chromosome. During the biosynthesis phase, new viral components are synthesized using the host's machinery. The maturation phase is when new virions are assembled within the host cell.

Finally, in the release phase, the host cell is lysed open by phage enzymes such as holin or lysozyme, freeing the mature viruses to infect new cells. The destruction of the host cell characterizes the lytic cycle, which is a productive infection leading to new progeny viruses.