AS Biology Core PrinciplesLipids 100’s of free ppt’s from www.pptpoint.com library
Aimso Elements of lipidso Structure of glycerol & fatty acidso Condensation reactions to form triglycerideso Phospholipids
Introduction to lipids
Introduction to lipidso Lipids contain the elements carbon, hydrogen and oxygen.o They have numerous functions, primarily energy stores in animals and plants.o Lipids consist of two types of molecules - glycerol & fatty acids.
Glycerolo A molecule of glycerol is made up of three carbon atoms.o Each of these has a hydroxyl group attached to it.o Hydrogen atoms occupy the remaining positions.
Fatty Acidso A single fatty acid molecule contains an acid (COOH) group attached to a hydrocarbon chain.o Hydrocarbon usually denoted by the letter ’R’.o Saturated = If every carbon atom in the chain is joined by a single C-C bond.o Unsaturated = at least one C=C bond.o Polyunsaturated = many double bonds.o Most animal fats are saturated while most plant fats are unsaturated.
Triglycerideso A triglyceride molecule is made of a glycerol molecule and three fatty acids.o The molecules join together through the process of condensation losing a molecule of water each time a link is made.o The link between the glycerol molecule & each fatty acid is an ‘Ester Link’.o The fatty acids in a lipid molecule can differ in length and can be saturated or unsaturated.
Phospholipidso In phospholipids one of the fatty acids of a triglyceride is substituted by a phosphate group.
Lipids & watero Triglycerides and phospholipids have hydrophobic and hydrophilic groups. o What does this mean? o To what use is this feature put in biology?
More Infoo To make further notes on Lipids : o Pages 11 & 12 in Collins o Pages 69 - 71 Roberts o www.mrothery.co.uk o www.learn.co.uk o www.bbc.co.uk/education/asguru/