What are leak channels characterized by?

Leak channels are specialized proteins located within cell membranes that facilitate the passive movement of specific ions across the membrane. They are characterized by being always open, which allows ions to flow freely down their concentration gradients. This continuous openness is essential for maintaining the resting membrane potential of cells, particularly in neurons and muscle fibers.

Because leak channels are always open, they play a crucial role in the balance of ion concentrations inside and outside the cell. This contrasts with other types of channels, such as gated channels, which are closed at rest and only open in response to certain stimuli or signals. Additionally, leak channels typically exhibit selectivity for specific ions, such as potassium or sodium, but their defining characteristic is their constant openness, leading to their role in establishing the electrochemical gradients necessary for various physiological processes.