Plasma Membrane of a cell consists of a bilayer of phospholipids with many different associated integral and peripheral proteins and glycoproteins (Fig. 2-2).

The cell’s plasma membrane, or plasmalemma, is only 7 – 10 nm thick, below the resolution of the light microscope.

• In very high magnification TEM pictures, such as Fig. 2-1a, the structure of the plasma membrane can be partially seen if the proteins associated with it internally and externally are abundant.
• A thick external coat of glycoproteins on the outside of the plasma membrane is called a glycocalyx.

How does the well-known diagram of the “fluid mosaic” membrane model shown in Fig. 2-2a correlate with the apparently three-layered membrane structure shown in the EM of Fig. 2-1a?

How would expect a cell’s glycocalyx to stain with alcian blue?

With the PAS reaction?

Let's now take a look at membrane bound organelles within the cell.