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 address the question of selecting the incorrect statement regarding the properties of single ion channels, we can break down the information provided in the video transcript step by step.

### Step-by-Step Solution:

1. **Understanding Single Ion Channels**: Single ion channels are specialized proteins that allow specific ions to pass through the cell membrane. Each channel is selective for a particular ion, such as sodium (Na+), potassium (K+), calcium (Ca2+), or magnesium (Mg2+).

2. **Transport Protein**: Single ion channels act as transport proteins. They facilitate the movement of ions across the membrane. For example, GLUT4 is a well-known transport protein, but it primarily transports glucose rather than ions. However, the concept of transport proteins is still applicable to ion channels.

3. **Rapid Changes in Shape**: Ion channels undergo rapid conformational changes when ions bind to them. This change in shape is crucial for the function of the channel, as it allows the selective passage of ions while preventing others from entering.

4. **Gated Channels**: Many ion channels are gated, meaning they can open or close in response to specific stimuli (e.g., voltage changes or ligand binding). This gating mechanism often requires energy, typically in the form of ATP.

5. **Movement Across the Membrane**: The statement that ion channels do not facilitate movement across the membrane is incorrect. Ion channels are specifically designed to allow ions to move across the membrane, which is their primary function.

### Conclusion:
Based on the analysis:
- The incorrect statement is that "movement across the membrane is not done by ion channels." This statement is false because the primary function of ion channels is indeed to facilitate the movement of ions across the membrane.