Given below some properties of transport mechanism. Which of these are true for the facilitated transport
(i) Require ATP energy
(ii) Highly selective
(iii) Uphill transport
(iv) Requires special membrane proteins
(v) Transport saturates

Options

A. (i),(ii),(iii) ,(iv)
B. (ii),(iv),(v)
C. (i),(iii),(v)
D. (ii),(iii),(iv),(v)

Answer

To determine which properties are true for facilitated transport, let's analyze each statement step by step:

1. **Require ATP energy**:
- Facilitated transport is a type of passive transport, meaning it does not require energy in the form of ATP. Instead, it relies on the concentration gradient, moving substances from an area of high concentration to an area of low concentration.
- **Conclusion**: This statement is **false**.

2. **Highly selective**:
- Facilitated transport involves specific membrane proteins that are selective for certain molecules. These proteins allow only particular substances to pass through the membrane, ensuring that the transport is selective.
- **Conclusion**: This statement is **true**.

3. **Uphill transport**:
- Uphill transport refers to moving substances against their concentration gradient, which requires energy. Facilitated transport, however, moves substances down their concentration gradient (from high to low concentration), which is considered downhill transport.
- **Conclusion**: This statement is **false**.

4. **Requires special membrane proteins**:
- Facilitated transport indeed requires specific membrane proteins (such as carrier proteins or channel proteins) to assist in the transport of substances across the cell membrane.
- **Conclusion**: This statement is **true**.

5. **Transport saturates**:
- In facilitated transport, there is a limit to how much substance can be transported at a given time because the available membrane proteins can become saturated. Once all the proteins are occupied, the rate of transport cannot increase further, leading to saturation.
- **Conclusion**: This statement is **true**.

### Summary of True Statements:
- The true properties of facilitated transport are:
- (ii) Highly selective
- (iv) Requires special membrane proteins
- (v) Transport saturates

### Final Answer:
The true statements regarding facilitated transport are (ii), (iv), and (v).