Go through the following statements
I. In active transport, pumps are proteins that use energy for transportation of molecules against the concentration gradient.
II. Carrier protein is very specific.
III. Transport rate reaches a maximum when all the active protein transporters are used and saturated

Options

A. All are correct
B. None is correct
C. l and Ill are correct
D. II and III are correct

Answer

To analyze the given statements about active transport in plants, we will evaluate each statement one by one.

### Step-by-Step Solution:

1. **Statement I: In active transport, pumps are proteins that use energy for transportation of molecules against the concentration gradient.**
- **Evaluation:** This statement is correct. Active transport involves the movement of molecules from an area of lower concentration to an area of higher concentration, which requires energy. The proteins that facilitate this process are known as pumps, such as the sodium-potassium pump, which actively transports sodium ions out of and potassium ions into the cell.

2. **Statement II: Carrier protein is very specific.**
- **Evaluation:** This statement is also correct. Carrier proteins are specialized proteins that transport specific substances across a cell membrane. Each carrier protein is designed to bind to a particular molecule or ion, ensuring that only specific substances are transported.

3. **Statement III: Transport rate reaches a maximum when all the active protein transporters are used and saturated.**
- **Evaluation:** This statement is correct as well. In active transport, there is a limit to how many molecules can be transported at once, which is determined by the number of available carrier proteins. Once all the carrier proteins are occupied (saturated), the transport rate cannot increase further, even if the concentration gradient continues to rise. This point is known as the saturation point.

### Conclusion:
All three statements are correct. Therefore, the answer is that all statements are true.