Which of the following are surface structures of a prokaryotic cell, but does not facilitate motility?

Options

A. Pili
B. Flagella
C. Fimbriae
D. Both (A) and (C)

Answer

To solve the question, we need to identify which surface structures of a prokaryotic cell do not facilitate motility. We will analyze each option provided.

### Step 1: Understand the structures
1. **Pili**: These are short, hair-like structures on the surface of prokaryotic cells. Their primary function is to help bacteria adhere to surfaces, which is important for infection. While they can assist in movement in some cases (like twitching motility), their main role is not motility.

2. **Flagella**: These are long, whip-like structures that are primarily responsible for the motility of prokaryotic cells. They enable the bacteria to move towards or away from stimuli. Therefore, flagella facilitate motility.

3. **Fimbriae**: Similar to pili, fimbriae are also surface structures that help bacteria adhere to specific receptors on surfaces. They are long and proteinaceous, and their main function is to assist in binding rather than movement.

### Step 2: Analyze the options
- **Pili**: While they can assist in movement, their main function is adherence, so they do not primarily facilitate motility.
- **Flagella**: They are responsible for motility, so they do not fit the criteria of the question.
- **Fimbriae**: Like pili, they are involved in adherence and do not facilitate motility.

### Step 3: Conclusion
Based on the analysis:
- **Pili and Fimbriae** are surface structures that do not facilitate motility.
- Therefore, the correct answer is **both A (Pili) and C (Fimbriae)**.

### Final Answer:
**Option D: Both A and C (Pili and Fimbriae)** are surface structures of a prokaryotic cell that do not facilitate motility.

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