Which structure enables bacteria to stick to surfaces and participates in genetic exchange during conjugation?

• A. Pili
• B. Capsule
• C. Endospore
• D. Cocci

Answer: (A)

Pili are hair-like projections on bacteria that enable two key interactions. Some pili (fimbriae) help the cell stick to surfaces and form communities, while others, the sex pili, establish contact between donor and recipient cells to transfer genetic material during conjugation. This combination of adhesion and the ability to mediate DNA transfer is why pili best fit the description in the question.

Capsules aid in protection and attachment to surfaces but don’t drive genetic exchange; endospores are dormant survival forms; cocci describe shape, not a transfer mechanism.