What structure in bacteria attaches to other cells in exchange for genetic material?

The pilus is a crucial structure in bacteria that facilitates the attachment to other cells for the purpose of exchanging genetic material. This process, known as conjugation, allows for the transfer of plasmids or other DNA fragments between bacterial cells, promoting genetic diversity and adaptation. The pilus is typically a thin, hair-like appendage that can extend and retract, effectively connecting two cells during the exchange.

In contrast, flagella are primarily used for mobility, enabling bacteria to swim through liquids rather than participating in genetic exchange. The capsule serves as a protective layer for some bacteria, contributing to their virulence and preventing desiccation, but it does not play a role in genetic transfer. The cell wall is a structural component providing shape and support to the bacterial cell, but like the capsule, it lacks the function of facilitating genetic exchange. Hence, the pilus stands out as the specific structure directly involved in the transfer of genetic material between bacterial cells.