Which pair of organelles have the same pH and ionic composition?
Ionic milieu of subcellular compartments reflects membrane permeability architecture and active pumping. The mitochondrial outer membrane contains abundant 19-stranded beta-barrel voltage-dependent anion channels, VDAC porins, present at high density allowing nonselective diffusion of solutes up to about 4 to 5 kilodaltons, including chloride, potassium, sodium, small metabolites, ATP, ADP, NADH and citrate. Because VDAC pores remain predominantly open under physiological low potentials, the intermembrane space equilibrates rapidly with cytosol via free diffusion, sharing near-identical pH aro
Ref: Nicholls & Ferguson, Bioenergetics, 4th ed., Chapter 3: Outer Membrane Permeability and Cytosol-Equilibrated Intermembrane Space.
