Select the incorrect statement for single ion channel :

Options

A. Transport proteins
B. Rapid change in shape
C. Gated channels
D. Movement across membranes

Answer

To solve the question regarding the incorrect statement for single ion channels, we need to analyze each statement provided in the question.

### Step-by-Step Solution:

1. **Understanding Single Ion Channels**:
- Single ion channels are specialized proteins that allow specific ions to pass through cell membranes. They play a crucial role in maintaining ion balance and electrical signaling in cells.

2. **Evaluating the First Statement**:
- The first statement claims that single ion channels are transport proteins.
- **Evaluation**: This statement is correct. Single ion channels indeed function as transport proteins that facilitate the movement of ions across membranes.

3. **Evaluating the Second Statement**:
- The second statement mentions a rapid change in shape.
- **Evaluation**: This statement is also correct. Ion channels can undergo conformational changes rapidly to allow ions to pass through when they open.

4. **Evaluating the Third Statement**:
- The third statement refers to gated channels.
- **Evaluation**: This statement is correct as well. Many ion channels are gated, meaning they open or close in response to specific stimuli, allowing selective ions to move across the membrane.

5. **Evaluating the Fourth Statement**:
- The fourth statement discusses movement across the membranes and its implications.
- **Evaluation**: This statement is incorrect. While single ion channels do allow ions to move across membranes, the statement suggests that this movement disrupts electrical neutrality, which is misleading. The opening of a single ion channel does alter the electrical charges on both sides of the membrane, but it does not inherently disrupt electrical neutrality in a way that is detrimental; rather, it is part of normal cellular function.

### Conclusion:
Based on the evaluations, the incorrect statement regarding single ion channels is the fourth statement.

### Answer:
The incorrect statement for single ion channels is: **Movement across the membranes.**

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