What are Lipids? – Nonpolar, organic molecules – Composed of hydrogen (H), carbon (C), and oxygen (O) – Lipids consist of two types of molecules - glycerol & fatty acids

Glycerol - an alcohol - Serves as backbone of the molecule

Fatty Acid 3 Fatty acids Long hydrocarbon chains

Biological Importance: – All lipids are insoluble in water – Lipids are a more efficient energy storage system than carbohydrates – become FAT STORAGE Energy stored in bonds of lipids – fats store 2.5 times as much energy per unit as carbs – Major component of cell membrane Cell membrane = Phospholipid bilayer

Lipids in the Cell Membrane Phospholipids have a hydrophyllic end and a hydrophobic end “Hydrophobic” – water fearing “Hydrophillic” – water loving These ends give the membrane many of its properties!!!

Checkpoint – Questions 1.Would it be more efficient to store energy as glycogen or as fat? Why??? 2.Why are lipids considered an organic molecule? 3.What does it mean to be hydrophobic? 4.What is the name of the lipid that makes up the cell membrane?

Types of fats Saturated fats have long chains with no double-bonds Unsaturated fats have double bonds between hydrogen and carbon

Special Lipids Triglycerides: composed of 3 molecules of fatty acids and 1 molecule of glycerol

Special Lipids Oils - lipids that are liquid at room temperature Fats - lipids that are solid at room temperature

Special Lipids Waxes – lipid that gives many substances a waterproofing cover Examples: surface of plant leaves, ear wax Steroids – lipids that cause changes within an organism Examples: nerve tissue,plant poisons, hormones, and venoms