Question

What portion of bacteriophage T4 enters E. coli?

a. no portion of phage T4 actually enters the bacterial cell
b. only the T4 genome enters the bacterial cell
c. the entire phage enters into the bacterial cell
d. only the tail fibers penetrate into the interior of the bacterial cell

Answer 1

Only the genome of bacteriophage T4 enters the E. coli cell during infection, using the tail structure to inject DNA while the rest of the phage remains outside.

Step-by-step explanation:

When bacteriophage T4 infects an E. coli bacterium, only its genome enters the bacterial cell. This occurs during the entry or penetration stage of the phage's lytic cycle. The T4 phage attaches to the bacterial surface receptors using its tail fibers and then injects its DNA into the E. coli cell through the tail structure, which acts like a hypodermic needle. The rest of the phage, including the tail and the protein coat (capsid), remains outside the bacteria.