Final answer:
Conjugation is the process by which bacteria exchange DNA between each other, involving the transfer of DNA through a connecting pilus from the donor to the recipient cell.
Step-by-step explanation:
When bacteria exchange DNA between each other, this process is known as conjugation. During conjugation, DNA is directly transferred from one prokaryote (donor) to another (recipient) via a specialized structure called a conjugation pilus, often referred to as the F pilus, or sex pilus.
The donor cell, which contains an F plasmid also known as the fertility factor, forms the F pilus that connects to the recipient cell, allowing for the transfer of genetic material, usually in the form of a plasmid. This DNA exchange mechanism is significant because it contributes to genetic variation and can lead to phenomena such as antibiotic resistance in bacteria. Conjugation, alongside transformation (uptake of DNA from the environment) and transduction (gene transfer via viruses), plays a crucial role in the horizontal gene transfer among prokaryotes.