Final answer:
The bacterial cell transferring chromosomal genes to F- cells and rarely causing them to become F+ is an Hfr cell, due to the transient nature of conjugation and large chromosomal size.
Step-by-step explanation:
The bacterial cell described in the question is an Hfr cell. This term stands for "high frequency of recombination," and it refers to the cellular process where the F plasmid has integrated into the bacterial chromosome. During conjugation, an Hfr cell can transfer chromosomal genes to an F- cell, but rarely turns them into F+ because the entire chromosome is too large to be transferred before the conjugation connection ends. Typically, only genes near the integration site of the F plasmid are transferred, and this process can be used to map the relative location of bacterial genes on the genome.