Transcriptionally active chromatin is

Options

A. Euchromatin
B. Heterochromatin
C. Both
D. None

Answer

To answer the question "Transcriptionally active chromatin is," we need to understand the types of chromatin and their characteristics. Here’s a step-by-step breakdown of the solution:

### Step-by-Step Solution:

1. **Understanding Chromatin**:
- Chromatin is a complex of DNA and proteins found in the nucleus of eukaryotic cells. It plays a crucial role in gene regulation and expression.

2. **Types of Chromatin**:
- There are two main types of chromatin: euchromatin and heterochromatin.
- **Euchromatin**: This type is loosely packed and is associated with active gene transcription.
- **Heterochromatin**: This type is tightly packed and is generally transcriptionally inactive.

3. **Characteristics of Euchromatin**:
- Euchromatin stains lighter under a microscope due to its less dense structure.
- It is accessible for transcription machinery, making it transcriptionally active.

4. **Characteristics of Heterochromatin**:
- Heterochromatin stains darker because it is more condensed.
- It is typically not accessible for transcription and is considered transcriptionally inactive.

5. **Conclusion**:
- Since the question asks for transcriptionally active chromatin, the correct answer is **euchromatin**.

### Final Answer:
Transcriptionally active chromatin is **euchromatin**.

---