Select the incorrect statement for properties of single ion channels

Options

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

Answer

To solve the question regarding the incorrect statement for the properties of single ion channels, we will analyze each provided statement step by step.

### Step-by-Step Solution:

1. **Identify the Statements**:
We have four statements regarding the properties of single ion channels:
- A) Transport protein
- B) Rapid change in shape
- C) Gated channel
- D) Movement across the membrane

2. **Analyze Statement A**:
- **Statement**: "Transport protein"
- **Analysis**: Ion channels are indeed specialized proteins that facilitate the transport of ions across the cell membrane. This statement is **correct**.

3. **Analyze Statement B**:
- **Statement**: "Rapid change in shape"
- **Analysis**: Ion channels can undergo rapid conformational changes to open or close in response to stimuli, allowing ions to pass through. This statement is also **correct**.

4. **Analyze Statement C**:
- **Statement**: "Gated channel"
- **Analysis**: Many ion channels are gated, meaning they can open or close in response to specific signals (like voltage changes or ligand binding). This statement is **correct**.

5. **Analyze Statement D**:
- **Statement**: "Movement across the membrane"
- **Analysis**: While ion channels facilitate the movement of ions, the phrasing "movement across the membrane" can be misleading. The ions move through the channel rather than across the membrane itself, as the channel provides a pathway through the lipid bilayer. Hence, this statement is **incorrect**.

6. **Conclusion**:
- The incorrect statement regarding the properties of single ion channels is **D) Movement across the membrane**.

### Final Answer:
The incorrect statement for properties of single ion channels is **D) Movement across the membrane**.

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