In some cyanobacteria, there are membranous extensions into the cytoplasm called ______which contain pigments.

Options

A. Chromatophores
B. mesosome
C. phycobilisomes
D. all of these

Answer

To answer the question regarding the membranous extensions in some cyanobacteria that contain pigments, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Cyanobacteria**: Recognize that cyanobacteria, also known as blue-green algae, are a group of photosynthetic bacteria that can produce their own food through photosynthesis.

2. **Identify the Structures**: The question asks for membranous extensions into the cytoplasm. In cyanobacteria, there are specific structures that serve this purpose.

3. **Differentiate Between Structures**:
- **Phycobolosomes**: These are protein assemblies involved in light harvesting but are not the extensions into the cytoplasm.
- **Mesosomes**: These are invaginations of the plasma membrane but do not specifically refer to the extensions containing pigments.

4. **Identify the Correct Structure**: The correct term for the membranous extensions that contain pigments in cyanobacteria is **chromatophores**. Chromatophores are specialized structures that house the pigments necessary for photosynthesis.

5. **Conclusion**: Therefore, the answer to the question is **chromatophores**.

### Final Answer:
In some cyanobacteria, there are membranous extensions into the cytoplasm called **chromatophores**, which contain pigments.

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