A membranous coiled semicircular structure attached to plasma membrane and found in blue -green algae is called

Options

A. Lamellasome
B. Lomasome
C. Mesosome
D. Microsome.

Answer

To answer the question, "A membranous coiled semicircular structure attached to plasma membrane and found in blue-green algae is called," we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question is asking for a specific structure that is both membranous and coiled, and is found in blue-green algae (which are also known as cyanobacteria).

2. **Identify the Options**: The options provided are:
- A) Lamella zone
- B) Loma zone
- C) Mesozoam
- D) Microzoam

3. **Analyze Each Option**:
- **Option A: Lamella zone**: This is described as a membranous coiled semicircular structure attached to the plasma membrane in cyanobacteria. This matches the description given in the question.
- **Option B: Loma zone**: This refers to an invagination of the cell membrane into the cytoplasm. It is not specifically a coiled structure and is found in some fungi and higher plants, making it incorrect for this question.
- **Option C: Mesozoam**: This is a folded invagination found in the plasma membrane of bacteria, which increases surface area for respiration. It does not match the description of being coiled and is not specific to blue-green algae.
- **Option D: Microzoam**: This is a fragment of the endoplasmic reticulum and is not found in living cells. It does not fit the criteria of the question.

4. **Conclusion**: Based on the analysis, the correct answer is **Option A: Lamella zone**. This structure is indeed a membranous coiled semicircular structure attached to the plasma membrane of blue-green algae.

### Final Answer:
**The correct answer is: Lamella zone.**