Sex pilli are present in

Options

A. Male Escheriahia coli
B. Female Escherichia coli
C. Diplococcus
D. All bacteria

Answer

To answer the question "Sex pili are present in," we will follow a step-by-step approach to understand the concept of sex pili and identify the correct answer from the options provided.

### Step-by-Step Solution:

1. **Understanding Pili**:
- Pili are short, hair-like structures found on the surface of prokaryotic cells (bacteria). They are thinner and shorter than flagella and play a role in movement and adherence to surfaces.

**Hint**: Remember that pili are different from flagella in terms of structure and function.

2. **Types of Pili**:
- There are different types of pili, including sex pili (also known as conjugation pili or F-pili). These structures are specifically involved in the process of conjugation, which is a form of genetic exchange between bacteria.

**Hint**: Focus on the specific function of sex pili in genetic exchange.

3. **Function of Sex Pili**:
- Sex pili have receptors that recognize recipient cells, allowing the transfer of genetic material from a donor cell during conjugation. This process is crucial for genetic diversity in bacteria.

**Hint**: Think about how sex pili facilitate the transfer of DNA between bacteria.

4. **Presence of Sex Pili**:
- Sex pili are predominantly found in male E. coli (a type of bacterium). They help stabilize the bacteria during the DNA transfer process.

**Hint**: Consider the specific type of bacteria where sex pili are found.

5. **Evaluating the Options**:
- The options given are:
1. Male stereocoli
2. Female stereocoli
3. Diplococcus
4. All bacteria
- Based on our understanding, sex pili are present in male E. coli, not in female E. coli, Diplococcus, or all bacteria.

**Hint**: Eliminate options that do not correspond to the presence of sex pili.

6. **Conclusion**:
- The correct answer is "Male stereocoli" (which refers to male E. coli). This is the only option that accurately reflects where sex pili are found.

### Final Answer:
Sex pili are present in **Male stereocoli** (male E. coli).