Lipids a large and varied group of organic

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Lipids: a large and varied group of organic compounds. Lipids include: Triglycerides Phospholipids

Lipids: a large and varied group of organic compounds. Lipids include: Triglycerides Phospholipids Waxes Cholesterol and Steroids Lipids are all non-polar and do not dissolve in water

Triglycerides are one of the most common types of lipids Triglycerides consist of

Triglycerides are one of the most common types of lipids Triglycerides consist of one molecule of glycerol bonded to three fatty acid molecules Each fatty acid is linked to the glycerol molecule by an ester bond Glycerol H H C C C OH OH Hydroxyl groups OH H

Fatty Acids: O General Formula: CH 3 (CH 2)n C OH Carboxyl group H

Fatty Acids: O General Formula: CH 3 (CH 2)n C OH Carboxyl group H H H H C C C H H H CH 3 CH 2 O C OH

H H H H C C C H H H O C OH Can

H H H H C C C H H H O C OH Can be drawn as: O C OH

Forming a monoglyceride: O H C OH Hydroxyl group and carboxyl group react O

Forming a monoglyceride: O H C OH Hydroxyl group and carboxyl group react O H H C OH H Ester bond C + H 2 O This is a condensation reaction

A triglyceride: H H C O C O H C O C H Can

A triglyceride: H H C O C O H C O C H Can be drawn as: Glycerol O Fatty acid Ester bond

To split these ester bonds and separate a fatty acid from glycerol we need

To split these ester bonds and separate a fatty acid from glycerol we need to add a molecule of water O H H C C C O H C OH OH + H 2 O H O This is a hydrolysis reaction C OH H

Uses of Lipids in Living Things 1. Long-term energy stores Human Adipose Tissue Plant

Uses of Lipids in Living Things 1. Long-term energy stores Human Adipose Tissue Plant Oils

2. Buoyancy for marine animals: lipids are less dense than water so help animals

2. Buoyancy for marine animals: lipids are less dense than water so help animals float 3. Insulation: a layer of fat beneath the skin cuts down heat loss

4. Production of water: fatty acids produce a lot of metabolic water when they

4. Production of water: fatty acids produce a lot of metabolic water when they are oxidised during respiration e. g. C 17 H 35 COOH + 26 O 2 18 CO 2 + 18 H 2 O (a typical fatty acid) Camels’ humps are made of fat

Homework: Compare the relative advantages and disadvantages to an organism of using carbohydrates and

Homework: Compare the relative advantages and disadvantages to an organism of using carbohydrates and lipids as energy stores To be handed in on a separate sheet of paper.