Conjugation is controlled by plasmids. Only plasmids with specific genes can undergo conjugation. Conjugation occurs in several steps.
- The donor cell has protein filaments on the outside of the cell called sex pili. These sex pili (singular pilus) seek out a recipient cell and attach to it.
- The attachment of the sex pili causes the two cells to fuse, creating a cytoplasmic bridge called the conjugation tube.
- At this point, the plasmid DNA is replicated and passes through the conjugation tube, into the recipient cell.
This completes the transfer and the cells separate.