Which potassium ions do leaky K channels primarily allow to diffuse?

Leaky potassium channels primarily allow potassium ions to diffuse across the cell membrane. This is crucial for maintaining the resting membrane potential of the cell. At rest, the inside of the cell is negatively charged compared to the outside, and this difference in charge is largely maintained by the movement of potassium ions.

Leaky K channels are specific for potassium, allowing K ions to move out of the cell passively. This movement is driven by the concentration gradient, as there is typically a higher concentration of potassium inside the cell compared to the outside. When potassium ions exit the cell through these channels, they help to maintain the negative charge inside the cell, which is essential for various physiological functions like action potentials in neurons and muscle cells.

The other ions listed, such as calcium, sodium, and chloride, have different roles in cellular function and are regulated by different types of channels. Calcium ions are typically involved in signaling pathways, sodium ions are crucial for generating action potentials, and chloride ions often play a role in maintaining osmotic balance and membrane excitability. However, leaky K channels specifically facilitate the diffusion of potassium ions, making this the correct choice.