LIPIDS The Molecules of Cells CH 3

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

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

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

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

Three Fatty Acids stearic acidoleic acidlinolenic acid

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

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