A phospholipid bilayer is made up of two layers of phospholipids, in which hydrophobic fatty acids are in the middle of the what?
cell wall
cells membrane
skin
plasma membrane
A phospholipid is made up of a polar, phosphorus-containing head, and two long fatty acid (hydrocarbon), non-polar "tails. " That is, the head of the molecule is hydrophilic (water-loving), and the tail is hydrophobic (water-fearing). Cytosol and extracellular fluid - the insides and outsides of the cell - are made up of mostly water. In this watery environment, the water loving heads point out towards the water, and the water fearing tails point inwards, and push the water out. The resulting double layer is called a phospholipid bilayer. A phospholipid bilayer is made up of two layers of phospholipids, in which hydrophobic fatty acids are in the middle of the plasma membrane, and the hydrophilic heads are on the outside. An example of a simple phospholipid bilayer is illustrated in Figure below .