Grana present in chloroplast refers to

Options

A. Stroma lamellae
B. Stracks of quantansomes
C. stacks of thylakoids
D. Double membranous envelops

Answer

**Step-by-Step Text Solution:**

1. **Understanding Chloroplast Structure**:
- Chloroplasts are double membrane-bound organelles found in plant cells. They consist of an outer membrane and an inner membrane.

2. **Identifying Thylakoids**:
- Within the chloroplast, there are structures called thylakoids. These are disc-shaped membranes that contain chlorophyll and are essential for the photosynthesis process.

3. **Formation of Grana**:
- Thylakoids stack on top of each other to form structures known as grana (singular: granum). Each granum consists of multiple thylakoids piled together.

4. **Stroma**:
- The fluid-filled space surrounding the grana is called the stroma. It contains enzymes, ribosomes, and DNA necessary for the chloroplast's functions.

5. **Stromal Lamellae**:
- Grana are interconnected by thin membranes called stromal lamellae, which help maintain the structure and organization of the thylakoids within the chloroplast.

6. **Evaluating Options**:
- Given the options in the question:
- Option 1 (stromal lamellae) is incorrect as it refers to the connecting structures, not the grana.
- Option 2 (stacks of quantosomes) is also incorrect; quantosomes are not a term used for grana.
- Option 3 (stacks of thylakoids) is correct as grana are indeed stacks of thylakoids.
- Option 4 (double membranous envelope) is incorrect as it refers to the overall structure of the chloroplast, not specifically to grana.

7. **Conclusion**:
- Therefore, the correct answer is that grana present in chloroplasts refer to "stacks of thylakoids."