LIPIDS The Molecules of Cells CH 3 Lipids

LIPIDS The Molecules of Cells CH 3

Lipids n n Lipids include fats, which are mostly energy-storage molecules These compounds are composed largely of carbon and hydrogen n They are grouped together because they are insoluble in water

Lipids n n n Fats, phospholipids and waxes include fatty acids Sterols have rigid backbone of four fused carbon rings (do not contain fatty acids) Fatty acids composed of n n Hydrocarbon chain -COOH (carboxyl group)

Lipids n Fats are lipids whose main function is energy storage n n They are also called triglycerides A triglyceride molecule consists of one glycerol molecule linked to three fatty acids Fatty acid

Unsaturated & Saturated Fats n n Unsaturated fats (plant oils) contain double bonds between carbons n Double bonds prevent them from solidifying at room temperature Saturated fats (lard) have single bonds between carbons, no double bonds n They are solid at room temperature

Three Fatty Acids stearic acid oleic acid linolenic acid

Phospholipids, waxes, and steroids are lipids with a variety of functions n n n Phospholipids are a main component of cell membranes Waxes form waterproof coatings Steroids are often hormones

Sterols n n n Contain no fatty acids Backbone form by four fused together carbon rings Cholesterol – most common type found in animals