Final answer:
F+ bacteria transfer genetic material to F- bacteria through the mating bridge of the conjugation pilus. During conjugation, DNA from the F plasmid and, potentially, chromosomal DNA is transferred, which may convert the recipient into an F+ cell or introduce new genes.
Step-by-step explanation:
An F+ bacterium transfers genetic material to an F- bacterium through conjugation using a conjugation pilus. Conjugation is a process where genetic information is directly transferred from a donor F+ bacterium, which contains the F plasmid (fertility factor), to a recipient F- bacterium that lacks the F plasmid. During conjugation, the F+ bacterium forms a conjugation pilus, which serves as a bridge connecting it to the F- cell. Through this bridge, a single strand of the F plasmid's DNA is transferred to the F- bacterium by rolling circle replication.
If the F plasmid has integrated into the donor bacterium's chromosome, creating an Hfr cell, then chromosomal DNA adjacent to the integration site can also be transferred. The process is usually interrupted before the entire chromosome is transferred due to the transient nature of the contact between the two bacteria.