Starch is not a lipid. It is one of two major carbon storage compounds that are found in some plants and microalgae. Lipids are groups of fat-soluble biological molecules, while starch is a complex carbohydrate.
The four major lipid groups are fats, phospholipids, steroids and waxes. Triglycerides, also known as fats, are the largest class of lipids. Their primary function is to store energy for later use. Phospholipids are derived from triglycerides; they form the basis of cellular membranes. Steroids are hydrophobic molecules that have a four fused carbon ring structure. Some common steroids are cholesterol, which is a precursor for the making of other steroids; the sex hormones progesterone, estrogen and testosterone; and cortisone. Waxes are composed of a long-chain alcohol and a fatty acid. Some animal fur and bird feathers are covered in a wax coating to repel water, while some fruits feature a wax coating that helps prevent water loss.