ABSTRACT
The yeast cell envelope includes the plasma membrane, the cell wall, and a slime layer all of which are anatomically distinct. This chapter describes the ultrastructure of the yeast cell envelope; documentation that is intrinsically important as well as being complementary to many biochemical and biophysical investigations. It discusses a detailed treatment of the principles and techniques of electron microscopy. Thin sectioning is probably the best approach for any initial study of cell structure. For electron microscopy this entails ultrathin sectioning of properly fixed and stained material, and requires the greatest effort in all aspects of specimen preparation. Although some microscopists consider permanganate to be a capricious fixative at best, in some cases it may be the only chemical fixative to adequately preserve membranous structure and to delineate unit membranes. The plasma membrane constitutes the innermost substructural component of the yeast cell envelope.
