A scientist observes a bacterium that has lost its ability to adhere to surfaces and form biofilms, yet its viability and motility remain unaffected. Which structure is most likely impaired in this bacterium?
Correct: C
Fimbriae (also known as pili) are short, hair-like protein appendages that project from the surface of many prokaryotic cells. Their primary function is to enable bacteria to attach to host cells or surfaces, contributing significantly to pathogenicity and biofilm formation. A flagellum is primarily for motility. Plasmids are extrachromosomal DNA that confer various traits, but direct adhesion is not their primary function. The cell wall provides structural integrity and protection, but its impairment would likely affect viability or cell shape before specific adhesion to surfaces for biofilm formation, especially if motility is unaffected.