sentences:  As a lecithin, phosphatidylethanolamine consists of a combination of glycerol esterified with two fatty acids and phosphoric acid.Whereas the phosphate group is combined with choline in phosphatidylcholine, it is combined with the ethanolamine in phosphatidylethanolamine.The two fatty acids may be the same, or different, and are usually in the 1,2 positions (though they can be in the 1,3 positions).