What process involves a bacterium using its pilus to transfer plasmid DNA to another bacterium?

• A. Transformation
• B. Transduction
• C. Conjugation
• D. Replication

Answer: (C)

Conjugation is the process where one bacterium transfers genetic material to another through direct contact, often facilitated by a structure known as a pilus. During conjugation, a donor bacterium with a specialized pilus can connect to a recipient bacterium. This connection allows the transfer of plasmid DNA, which is often responsible for traits such as antibiotic resistance.

The role of the pilus is crucial, as it serves as a bridge that physically links the two bacterial cells, promoting the exchange of genetic material. This method of horizontal gene transfer is significant in bacterial evolution and adaptation, as it allows for rapid dissemination of advantageous traits across a population.

In contrast, transformation involves the uptake of naked DNA from the environment by a bacterium, while transduction refers to the transfer of DNA from one bacterium to another via a bacteriophage (virus). Replication, on the other hand, pertains to the process by which a bacterium duplicates its own DNA for cellular division and is not related to the transfer of DNA between different bacterial cells.