Ground substance of chloroplast is

Options

A. Stoma
B. Stroma
C. Granum
D. Cisterna.

Answer

**Step-by-Step Solution:**

1. **Understanding the Structure of Chloroplast:**
- Chloroplasts are organelles found in plant cells that are responsible for photosynthesis. They have a double membrane structure, which means they are surrounded by two layers of membranes.

2. **Identifying the Ground Substance:**
- The ground substance within the chloroplast is known as the stroma. This is the fluid-filled space that surrounds the thylakoids and is essential for the photosynthetic process.

3. **Components of the Chloroplast:**
- Within the chloroplast, there are structures called thylakoids, which are stacked in piles known as grana (singular: granum). The thylakoids are where the light-dependent reactions of photosynthesis occur.
- The stroma, on the other hand, is where the light-independent reactions (Calvin cycle) take place.

4. **Function of the Stroma:**
- The stroma contains enzymes necessary for the dark reactions (Calvin cycle) of photosynthesis. It is also where the chloroplast's own DNA is located.

5. **Conclusion:**
- Therefore, the ground substance of the chloroplast is the stroma.

**Final Answer:**
The ground substance of the chloroplast is the stroma.

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