Question

During conjugation, the chromosome in the Hfr strain is first ______ , then transferred into the F— cell, where it may_______ with the homologous region of the recipient cell's chromosome.

Answer 1

During conjugation, the chromosome in an Hfr strain is first nicked, then transferred to an F− cell where it may recombine with the homologous region of the recipient's chromosome.

Step-by-step explanation:

During conjugation, the chromosome in the Hfr strain is first nicked, then transferred into the F− cell, where it may recombine with the homologous region of the recipient cell's chromosome.

An Hfr cell, which contains the F plasmid integrated into its chromosome, can transfer chromosomal DNA to an F− cell through conjugation. The process begins with rolling circle replication where the bacterial chromosome is nicked at the insertion site of the F plasmid, and the displaced strand is transferred. However, since the conjugation period is temporary and contact between cells is transient, not all of the chromosome is usually transferred. Genes closer to the integration site are more likely to be transferred and recombined.