Bacteria have nuclear material

Some bacteria have extra-chromosomal DNA called as plasmid

Plasmids are self replicating units. Plasmids code for sex pilus.

Plasmids are self replicating units.

Similar plasmids usually do not stay in the same bacterial cell.

They form conjugation tubes with neighboring bacteria with the sex pilus. Bacteria having sex pilus are F+ and those not having it are F-

Copy of the plasmid is transported across the conjugation tube to the F- bacterium

Copy of the plasmid is transported across the conjugation tube to the F- bacterium

Thus the F- bacterium becomes F+.

Many different genes especially those important in drug resistance are transmitted between bacteria through the plasmids.