Figure 2.

(A) Major electrochemical gradients for ions in the mitochondria. Chloride and larger organic ions have been ignored for clarity. The direction of the arrows indicates that of the concentration gradient, and the size of the arrow is roughly proportional to its magnitude. (B) Schematic representation of the reciprocal interactions between ion gradients and all aspects of mitochondrial physiology. Transport of Ca²⁺, H⁺, and K⁺ depend on Δψ_m, as ATP synthesis does. ATP modulates the permeability of some channels and is required for active transport and the maintenance of gradients. K⁺ transport is crucial for determining mitochondrial volume, which affects Δψ_m and ATP synthesis.