bacterial conjugation is a process of genetic transfer between bacterial cells that requires direct contact between the cells many but not all species of bacteria can conjugate conjugation can occur between cells of the same species or even between cells of two different species a small DNA circle or plasmid called the F factor is required for conjugation the F factor stands for fertility factor strains of bacteria containing the F factor are called F plus those without it are called F minus and F plus cell or a donor produces a structure called a pilus to connect with another recipient cell to begin conjugation the F factor is cut at a specific region called the origin of transfer by a protein assembly called the relaxer cell which associates with a strand to be transferred or the T DNA strand accessory proteins of the relaxants Lamar released but a portion of the relaxer zone called the relaxation remains attached to the T DNA this t DNA relaxes complex is recognized by a coupling factor and transferred to the exporter a complex in the f+ cell that is contiguous with the pilus the exporter pumps the T DNA relaxes complex into the recipient cell once the entire T DNA molecule is transferred to the recipient cell relaxes joins the ends to make a circular DNA molecule as the T DNA is transferred to the recipient cell it is replicated to become double stranded in the donor cell the F factor DNA was also replicated to become double stranded this actually occurred as the T DNA was being transferred to the recipient cell in the end most cells wind up with a complete double-stranded copy of the F factor their connection through the pilot is released and each is now an F+ cell that can go on to conjugate with other cells