It is not characteristic of active transport

Options

A. Highly selective
B. Insensitive to inhibitors
C. Uphill transport
D. Transporter saturates

Answer

To determine which option is not characteristic of active transport, we can analyze the characteristics of active transport step by step.

### Step-by-Step Solution:

1. **Understanding Active Transport**:
- Active transport is the process by which cells move ions or molecules across a membrane against their concentration gradient. This process requires energy, typically in the form of ATP.

2. **Characteristic 1: Highly Selective**:
- Active transport is indeed highly selective. It transports specific ions or molecules rather than allowing all substances to pass through. This characteristic is true for active transport.

3. **Characteristic 2: Insensitive to Inhibitors**:
- This characteristic is incorrect. Active transport mechanisms are sensitive to inhibitors. Certain substances can inhibit the function of transport proteins, affecting the transport process. Therefore, this statement is not a characteristic of active transport.

4. **Characteristic 3: Uphill Transport**:
- Active transport is characterized by uphill transport, meaning it moves substances from areas of lower concentration to areas of higher concentration, which requires energy. This characteristic is true for active transport.

5. **Characteristic 4: Transport Saturates**:
- Active transport can saturate, meaning that after a certain point, the transport proteins can become fully occupied, and no additional ions can be transported. This characteristic is also true for active transport.

### Conclusion:
The option that is not characteristic of active transport is **"Insensitive to inhibitors."**