Cellulose and chitin are examples of structural polysaccharides. Cellulose is the most abundant organic compound on earth. It is made of glucose, like starch, but they differ in the type of 1-4 linkage. A group of polymers that have one characteristic in common, they do not mix with water. They are hydrophobic.
Some important groups are fats, phospholipids, and steroids.
The bond connecting the glycerol and fatty acids in the fat molecule is called an ester bond. The saturated fatty acids do not contain any double bonds between the carbons, while the unsaturated fatty acids contain one or more double bonds between the carbons. These double bonds cut down on the number of hydrogen atoms that can be attached to the carbon in the molecule. This causes the molecule to bend or kink at each of the double bond sites. These molecules are found making up the plasma membrane of cells.