Question

During penetration of E. coli by the T4 phage

a) Lysozyme is used to allow entry of the phage capsid.
b) The tail acts as a 'hypodermic needle', injecting the phage DNA into the cell.
c) The protein fibers digest a hole in the cell wall.
d) The bacterial receptor molecules open a hole through the cell wall

Answer 1

During the penetration of E. coli by T4 phage, the phage's tail acts like a hypodermic needle, injecting its DNA into the bacterial cell. The protein coat remains outside, and the lytic cycle proceeds with the synthesis of new phage components, maturation, and eventual release via lysis.

Step-by-step explanation:

The question pertains to the lytic cycle of T4 bacteriophage infection in E. coli. In this context, the correct answer to the student's question is b) The tail acts as a 'hypodermic needle', injecting the phage DNA into the cell. The lytic cycle involves several steps, beginning with phage attachment to the bacterial cell and culminating in the release of new virions following cell lysis. Specifically, during penetration, the bacteriophage attaches to the cell via its tail fibers to specific surface receptors on the E. coli. It then uses the contraction of the tail sheath, functioning similarly to a hypodermic needle, to directly inject its DNA through the bacterial membranes into the bacterial cytoplasm. The phage's protein coat, including the head and other structural components, does not enter the bacterium.