What process involves the exchange of plasmids between two bacterial cells?

Conjugation is the process that specifically involves the exchange of plasmids between two bacterial cells. During this process, one bacterium transfers genetic material, typically in the form of a plasmid, to another bacterium through direct cell-to-cell contact. This transfer usually occurs via a structure called a pilus. Conjugation plays a vital role in the horizontal gene transfer among bacteria, allowing them to share traits such as antibiotic resistance or metabolic capabilities, enhancing their adaptability and evolution.

In contrast, transcription refers to the process of synthesizing RNA from a DNA template, which is fundamental to gene expression but does not involve plasmid exchange. Transformation involves the uptake of free DNA from the environment by a bacterial cell, which can lead to genetic changes but does not include direct transfer between cells. Transduction is a process where bacteriophages transfer genetic material from one bacterium to another, but it does not specifically involve plasmid exchange. Thus, conjugation stands out as the unique mechanism for the direct transfer of plasmids between bacterial cells.