The Phospholipid Page
Phospholipids are probably the simplest part of the cell membrane, so this is a pretty short page. The membrane is also referred to as a "bilipid layer" because it's made up of...two lipid layers!! The phospholipids are the lipids in these layers. Phospholipids have a polar head (which is a phosphorous group) and two nonpolar tails (which are fatty acids). The polar- and nonpolar-ness (a.k.a. polarity) of these molecules is the key to the way the membrane itself is put together, which is discussed in the Plasma Membrane section.
Here's a picture of a single phospholipid, although there are two layers of them in a membrane so there would usually be two together.
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