AQA AS Biology: Revision Notes

CONTENTS 1.1.1 Biological Molecules: Key Terms 1.1.2 Biological Molecules: Reactions 1.1.3 Monosaccharides 1.1.4 Glucose 1.1.5 The Glycosidic Bond 1.1.6 Chromatography: Monosaccharides 1.1.7 Disaccharides 1.1.8 Starch & Glycogen 1.1.9 Cellulose 1.1.10 Biochemical Tests: Sugars & Starch 1.1.11 Finding the Concentration of Glucose 1.1.1 BIOLOGICAL MOLECULES: KEY TERMS Biological Molecules: Key Terms There is much variety of life within and between organisms but the biochemical basis of life is similar for all living things The key molecules that are required to build structures that enable organisms to function are: Carbohydrates Proteins Lipids Nucleic Acids Water Monomers are the smaller units from which larger molecules are made Polymers are molecules made from a large number of monomers joined together in a chain AQA AS Biology Revision Notes 1.1 Biological Molecules: Carbohydrates YOUR NOTES ⬇ © Save My Exams Ltd AQA AS Biology Resources REVISION NOTES TOPIC QUESTIONS PAST PAPERS Page 2 AQA AS Biology Revision Notes 1.1 Biological Molecules: Carbohydrates YOUR NOTES ⬇ © Save My Exams Ltd AQA AS Biology Resources REVISION NOTES TOPIC QUESTIONS PAST PAPERS Page 3 The key biological molecules for living organisms AQA AS Biology Revision Notes 1.1 Biological Molecules: Carbohydrates YOUR NOTES ⬇ © Save My Exams Ltd AQA AS Biology Resources REVISION NOTES TOPIC QUESTIONS PAST PAPERS Page 4 Carbohydrates, proteins, lipids and nucleic acids contain the elements carbon (C) and hydrogen (H) making them organic compounds Carbon atoms are key to the organic compounds because: Each carbon atom can form four covalent bonds – this makes the compounds very stable (as covalent bonds are so strong they require a large input of energy to break them) Carbon atoms can form covalent bonds with oxygen, nitrogen and sulfur Carbon atoms can bond to form straight chains, branched chains or rings Carbon compounds can form small single subunits (monomers) that bond with many repeating subunits to form large molecules (polymers) by a process called polymerisation Macromolecules are very large molecules That contain 1000 or more atoms therefore having a high molecular mass Polymers can be macromolecules, however not all macromolecules are polymers as the subunits of polymers have to be the same repeating units Carbohydrates Carbohydrates are one of the main carbon-based compounds in living organisms All molecules in this group contain C, H and O As H and O atoms are always present in the ratio of 2:1 (eg. water H2O, which is where ‘hydrate’ comes from) they can be represented by the formula Cx (H2O)y The three types of carbohydrates are monosaccharides, disaccharides and polysaccharides