Starch is insoluble in water yet it is accumlated in large quantities in potato because

Options

A. It is synthesised in potato fuber itself
B. It is translocated from the leaves to the potato tuber in the form of sugar
C. Soil micro-organism deposit starch in tuber
D. It is useful consumption

Answer

**Step-by-Step Solution:**

1. **Understanding Starch and Its Properties:**
- Starch is a polysaccharide made up of glucose units. It is insoluble in water, which means it does not dissolve and can accumulate without affecting the osmotic balance of the cells.

2. **Photosynthesis and Glucose Production:**
- Plants produce glucose through the process of photosynthesis in their leaves. This glucose is a simple sugar that can be used immediately for energy or converted into other forms for storage.

3. **Need for Storage:**
- Since glucose is an osmotic solute, storing it directly in its form can lead to osmotic pressure changes in the plant cells, which can be harmful. Therefore, it is not practical for plants to store glucose directly.

4. **Conversion of Glucose to Sucrose:**
- To avoid the issues associated with storing glucose, plants convert glucose into sucrose, which is a disaccharide. Sucrose is less reactive and does not affect the osmotic balance as much as glucose would.

5. **Transport of Sucrose:**
- Sucrose is then transported from the leaves to other parts of the plant, such as the potato tubers, where it can be stored for later use.

6. **Conversion of Sucrose to Starch:**
- In the potato tubers, sucrose is further converted into starch for long-term storage. This conversion allows the plant to store energy without affecting the osmotic potential of the cells.

7. **Accumulation of Starch:**
- As a result, large quantities of starch can accumulate in potatoes, providing a reserve of energy that the plant can utilize when needed, especially during periods when photosynthesis is not occurring (e.g., winter).

**Final Answer:**
Starch is accumulated in large quantities in potatoes because glucose produced in the leaves is converted to sucrose for transport and then stored as starch in the tubers, which is insoluble in water and does not affect osmotic balance.

---