Final answer:
Hfr cells in bacterial conjugation have a high frequency of recombination, allowing for the transfer of chromosomal DNA. Their integrated F plasmid genes are readily expressed, enabling conjugation with recipient F- cells.
Step-by-step explanation:
The primary characteristic of Hfr cells in bacterial conjugation is that they have a high frequency of recombination. When recipient F cells receive genetic information from Hfr cells through conjugation, there is a high likelihood of recombination occurring, leading to the transfer of chromosomal DNA from the donor to the recipient cell. The Hfr cell's integrated F plasmid genes are readily expressed, allowing the formation of sex pili and conjugation with an F- cell.