Tails of the phospholipids in the phospholipid bilayer are hydrophobic, consisting of fatty acid chains. <span>Phospholipids are composed of two fatty acids, glycerol and phosphate groups, forming an amphipathic molecule. Amphipathic molecules are built from hydrophilic (water-loving) and hydrophobic (not attracted to water) molecules. The phospholipids in the plasma membrane are arranged in two layers, called a phospholipid bilayer. Hydrophobic molecules (fatty acids) are on the interior of the membrane, whereas the water-loving heads (phosphate head) point outwards, toward either the cytoplasm or the fluid that surrounds the cell. The head group and fatty acids are attached <span>to </span>a glycerol unit.</span>
In exothermic reactions, the products have higher energy than the reactants, and in endothermic reactions, the reactants have higher energy than the products.
