Biology 1.2 Lipids 0.0 / 5 ? BiologyBiological molecules, organic chemistry and biochemistryASWJEC Created by: DanCreated on: 04-01-14 17:20 What difference do lipids have to carbohydrates in organic elements? Like carbohydrates, lipids contain carbon, hydrogen and oxygen. But in proportion to carbon and hydrogen they contain less oxygen 1 of 18 What is a triglyceride? A combination of 3 fatty acids and a glycerol molecule 2 of 18 In a lipid what molecules stay the same and what will varey? Glycerol stays the same but the fatty acid component varies 3 of 18 How are triglycerides formed? Fatty acids join to glycerol in a condensation reaction where three molecules of water a removed 4 of 18 What bond is formed in place of the 3 water molecules? An oxygen bond (ester bond) is formed between the glycerol and fatty acid 5 of 18 Describe a fatty acid molecule to the best of your ability It is an organic molecule with a -COOH group attached to a hydrocarbon tail. 6 of 18 What is a 'saturated' fat? A hydrocarbon with no carbon-carbon double bond 7 of 18 What if a double bond is present? Then the fat is unsaturated 8 of 18 State an important chemical property of lipids They are insoluble in water but dissolve in organic solvents such as acetone and alcohol 9 of 18 Which lipid contributes mostly to heart disease? Saturated 10 of 18 Why do fats make good energy storage? They contain more Carbon-Hydrogen bonds than carbohydrates 11 of 18 Name and explain one role of a triglycerol Produces a metabolic water when oxidised, important for animals that do not drink much water (desert animals) 12 of 18 Name 3 other roles of a lipid Waterproofing, Protection and insulation 13 of 18 How are phospholipids different from lipids? One fatty acid group is replaced with a phosphate group which is polar and soluble in water 14 of 18 What is meant by polar? Molecules that have two ends or poles that interact differently to water and fat 15 of 18 Which part of the phospholipid molecule is hydrophobic? The 2 fatty acid tails 16 of 18 The head is hydrophilic. What does this mean? That its attracted to water but not fat and is polar 17 of 18 Why are phospholipids important in a plasma membrane? Phospholipids allow lipid soluble substances to enter and leave the cell and prevent water soluble substances entering and leaving the cell 18 of 18
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