By Alyssa, Bronte, Conrad, Dale, and Kevin Christopher LIPIDS

What are Lipids? Lipids include but are not limited to fats – Fats include butter, lard, oils, etc. Organic compounds, generally non-polar Can be simple or complex Simple lipids: contain carbon, hydrogen, oxygen. E.g. Triglycerides (3 fatty acids and glycerol), fat found in butter, lard, oils Complex lipids: phospholipids found in cells and bacteria, steroids, hormones, glycolipids (lipids with sugar molecules), fat soluble vitamins (A, D, E, and K)

Functions of Lipids Concentrated source of food energy, yields about twice as many calories as other normal food sources – 1g of fat = 9 calories Some lipids act as structural components (part of membranes of cells) – E.g. Phospholipids make up the phospholipid bilayer Protection and insulation for our organs – “Cushion” between skin and organs

Monomers Triglycerides: – Glycerol molecules each bond to three fatty acids Carboxylic acids with long hydrocarbon chains(tails) Steroids – Four fused rings of carbon molecules

Monomers Cont. Phospholipids – A phosphate group, diglyceride, and simple organic molecules

Vs. Unsaturated fats have double bonds between carbon atoms, saturated fats have no double bonds Fats can be neutral if they have no groups which may become charged or ionized Double bonds in unsaturated fats form when the number of hydrogens is less than 2 per Carbon

Saturated Vs. Unsaturated Cont. When a glycerol molecule reacts with 3 fatty acid molecules, it has 3 hydroxyl groups, and can form 1 fat molecule and 3 water molecules Larger fat molecules are formed by dehydration synthesis in the forward direction.

Types of Lipids Neutral FatsPhospholipidsSteroids Composed of carbon and oxygen molecules with 3 fatty acid tails Hydrophobic Composed of carbon and oxygen molecules with 2 fatty acid tails, and a negatively charged phosphate group Phosphate group is hydrophilic Distinguished by a four ring carbon skeleton Vary depending on functional groups

Neutral Fats Basic lipids, including saturated and unsaturated fats Stores energy – In animals, found in fat (in mammals, stored in specialized apidose cells) – In plants, usually found in the form of starch

Phospholipids Forms the phospholipid bilayer, the major component of cell membranes – Due to polar head and non-polar body, phospholipids form a micelle in water – The bilayer is arranged such that the polar phosphate groups face outwards, in contact to the aqueous solutions inside and outside the cell Other molecules may be bonded to the polar phosphate group, giving a large variety to phospholipids

Steroids Includes cholesterol (a major component of animal cell membranes) and hormones (many built from the basic cholesterol molecular structure) Many different kinds exist, depending on the varying functional groups attached to the basic structure

Works Cited 1%20lectures/biochemistry/biochemi.htm 1%20lectures/biochemistry/biochemi.htm %20lectures/Biochemistry/phospholipid_bilayer.gif 1%20lectures/Biochemistry/phospholipid_bilayer.gif