In EColi,λ DNA Integrates into Which Site on the Bacterial Chromosome

Question

In E.coli,λ DNA integrates into which site on the bacterial chromosome?
A)ori
B)trp
C)bio
D)gal
E)att

Accepted Answer

The λ phage integrates into the bacterial chromosome at a specific site known as att (attachment site), also known as attB on the bacterial chromosome and attP on the phage DNA. This integration takes place through the action of the phage-encoded Integrase enzyme which catalyzes site-specific recombination between the attB and attP sites, resulting in a stable integrated prophage. The other options listed, (A) ori, (B) trp, (C) bio, and (D) gal, are all genes found on the E. coli chromosome, but none of them are the integration site for λ phage.