Which best describes the function of a gated channel?

A gated channel is specialized for the selective passage of ions across a cell membrane, and its defining characteristic is that it opens in response to specific stimuli. This can include changes in voltage across the membrane, the binding of a molecule, or mechanical forces. When the appropriate stimulus is present, the channel undergoes a conformational change that allows ions to flow through, adhering to the principles of facilitated diffusion, which allows ions to move down their concentration gradient.

The other options do not accurately describe the fundamental function of gated channels. For instance, channels that constantly allow ions to pass are referred to as leak channels, which differ from gated channels due to their inability to open and close in response to stimuli. While some channels can facilitate the movement of water, perhaps in the case of aquaporins, this does not encompass the full range of gated channels. Stimulating hormone release is typically associated with an entirely different set of cellular mechanisms, including signal transduction pathways rather than the direct action of gated ion channels.