Which of the following structural features of \( E \). coli is most responsible for the signs and symptoms of a urinary tract infection? View Available Hint(s) Cell wall Flagella Ribosomes Fimbriae

**Fimbriae** are the structural features of *E. coli* most responsible for the signs and symptoms of a urinary tract infection (UTI). **Explanation:** - **Fimbriae:** These are hair-like appendages on the surface of *E. coli* that allow the bacteria to adhere to the epithelial cells lining the urinary tract. This attachment is crucial for the establishment and persistence of the infection, leading to the inflammatory responses and symptoms associated with UTIs. - **Flagella:** While flagella enable bacterial motility, helping *E. coli* move within the urinary tract, they are not directly responsible for the symptoms of UTIs. - **Cell Wall:** The cell wall provides structural integrity to the bacteria but does not play a specific role in causing the symptoms of UTIs. - **Ribosomes:** These are involved in protein synthesis within the bacteria and are not directly linked to UTI symptoms. **Correct Answer:** **Fimbriae**