Which of the following is not common between facilitated transport and active transport?

Options

A. Uphill transport
B. Highly selective
C. Transport saturates
D. Requirement of special membrane proteins

Answer

To determine which of the following is not common between facilitated transport and active transport, we need to analyze the characteristics of both transport mechanisms:

1. **Understanding Facilitated Transport**:
- Facilitated transport (or facilitated diffusion) is the process where substances move across a membrane with the help of special membrane proteins.
- This process does not require energy (ATP) and occurs down the concentration gradient (from high to low concentration).

2. **Understanding Active Transport**:
- Active transport is the movement of substances across a membrane against their concentration gradient (from low to high concentration).
- This process requires energy (usually in the form of ATP) and also involves special membrane proteins.

3. **Analyzing the Options**:
- **Uphill Transport**: This is characteristic of active transport, as it moves substances against their concentration gradient. Facilitated transport does not involve uphill transport; it is always downhill.
- **Highly Selective**: Both facilitated transport and active transport are selective in what they transport.
- **Transport Saturates**: Both transport mechanisms can become saturated when all available transport proteins are occupied.
- **Requirement of Special Membrane Proteins**: Both processes require specific membrane proteins to facilitate the transport of substances.

4. **Conclusion**:
- The only option that is not common between facilitated transport and active transport is "uphill transport." Facilitated transport is characterized by downhill transport, while active transport is uphill.

Thus, the answer to the question is **uphill transport**.