Which feature of lipid bilayers makes them selectively permeable?
Selective permeability originates from continuous oily interior separating cytosol from extracellular milieu. Phospholipid tails containing fourteen to twenty four carbon hydrocarbon chains exclude water creating low dielectric slab with Born energy penalty greater than one hundred fifty kilojoules per mol for moving sodium potassium chloride through effectively blocking ions and large polar molecules like glucose nucleotides sucrose. Small nonpolar gases oxygen carbon dioxide nitrogen dissolve readily and cross by solubility diffusion while water crosses slowly via transient pores permeabilit
Ref: Alberts et al., MBOC 7th ed., Chapter 11: Permeability of hydrophobic core and channels.
