Composition, structure and phase transition in yeast fatty acid auxotroph membranes: Spin labels and freeze‐fracture

Fatty acid desaturase mutant yeast cells have been enriched with 2 fatty acids having substantially different physical properties. Differences in fatty acid composition are reflected in the ESR determined phase transitions and the freeze‐fracture morphology of the tonoplast. In these cells, fatty acid composition, rather than the position of the phase transition relative to growth temperature, appears to be the more important variable in determining membrane morphology. The freezing process used in the freeze‐fracture technique does not appear to cause a demixing of the lipid components of the membrane.