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F Plasmid | Conjugative Plasmid | F Factor | Hfr | F+ F Prime |

The F or fertility plasmid also called the sex factor or fertility factor is a conjugative plasmid found in several bacteria... This plasmid control sexual functions of bacteria with a fertility inhibition (Fin) system. It  allows genes to be transferred from one bacterium carrying the factor to another bacterium lacking the factor by conjugation. The cell possessing the F factor is designated as “F+ cell” and acts as donor .... a cell devoid of this factor is designated as “F– cell” and acts as recipient during conjugation. When an F+ cell conjugates/mates with an F− cell, the result is two F+ cells, both capable of transmitting the plasmid to other F− cells by conjugation. A pilus on the F+ cell interacts with the recipient cell allowing formation of a mating junction, the DNA is nicked on one strand, unwound and transferred to the recipient The F factor can exist independent of the host chromosome, or it may become integrated into it. The bacterial cell in which the Factor is integrated into the chromosome is called an Hfr that is high frequency recombination cell.