1.1

• Inorganic ion


  Mineral needed by organisms in small or trace amounts
• All organisms need inorganic ions to survive; these inorganic ions are often called minerals
• Micronutrients


  Minerals needed in minute (trace) concentrations e.g. copper and zinc
• Macronutrients


  Minerals needed in small concentrations e.g. magnesium and iron
• Organic molecules have a high proportion of carbon and hydrogen atoms
• Inorganic molecules have no more than one carbon atom
• Dipole


  A polar molecule which has a positive and negative charge, separated by a very small distance
• Hydrogen bond


  The weak attractive force between a hydrogen atom (with a partial positive charge) and an atom with a partial negative charge, usually oxygen or nitrogen
• Water


  • It is a solvent
  • It is a transport medium
  • Chemical reactions take place in it
  • It has a high specific heat capacity
  • It has a high latent heat of vaporisation
  • It exhibits cohesion
  • It has high surface tension
  • It has a maximum density at 4°C
• Triose


  Monosaccharide with 3 carbon atoms, important in metabolism
• Pentose


  Monosaccharide with 5 carbon atoms, constituents of nucleotides
• Hexose


  Monosaccharide with 6 carbon atoms, glucose is a source of energy
• Isomers


  Molecules with the same chemical formula and number of atoms, but differently arranged
• Glycosidic bond


  Bond formed between two monosaccharides during condensation
• Condensation reaction


  Water is chemically removed to form a bond between adjacent monomers
• Hydrolysis


  Water is chemically added to break a bond between monomers
• Disaccharides and their component monosaccharides

  • Maltose: Glucose + Glucose
  • Sucrose: Glucose + Fructose
  • Lactose: Glucose + Galactose
• Reducing sugars


  Monosaccharides and some disaccharides that can reduce copper(II) sulfate to form a brick-red precipitate
• Non-reducing sugars


  Disaccharides like sucrose that do not reduce copper(II) sulfate
• Starch


  • It is made up of α-glucose monomers
  • It has two types: amylose (unbranched) and amylopectin (branched)
  • It is compact and has no osmotic effect on the cell
• Glycogen


  • It is similar in structure to amylopectin
  • It has shorter chains and more branch points than amylopectin
• Cellulose


  • It consists of long, parallel chains of β-glucose units
  • Adjacent glucose molecules are rotated by 180° allowing hydrogen bonding
  • Cellulose is unreactive, stable and has high tensile strength
• Chitin


  • It has a similar structure to cellulose but with acetylamine groups
  • Like cellulose, it forms cross-linked parallel chains
• Triglycerides


  The most common type of lipid, fats and oils
• Ester bond


  The bond formed between glycerol and fatty acids in triglycerides
• Unsaturated fatty acids

  • Have double bonds between carbon atoms, making them melt more easily
• Saturated fatty acids


  • Have no double bonds, carry the maximum number of hydrogen atoms, and are solid
• Atherosclerosis


  Fatty deposits in the coronary arteries
• Hypertension


  High blood pressure
• Contributory factors to heart disease

  • Diet high in saturated fatty acids
  • Smoking
  • Lack of exercise
  • Ageing
• Lipid and protein absorption

  1. Food absorbed at small intestine

  2. Lipids and proteins combine to make lipoproteins

  3. Lipoproteins travel in blood stream
• Diet high in saturated fats

  Increases low-density lipoproteins (LDL)
• Atheroma


  Fatty material deposited in coronary arteries, restricting blood flow and oxygen delivery to heart
• Restricted blood flow


  Can result in angina
• Coronary arteries completely blocked

  Myocardial infarction or heart attack occurs
• Diet high in unsaturated fats

  Increases high-density lipoproteins (HDL)
• HDL:LDL ratio


  The higher the ratio, the lower the risk of cardiovascular and coronary heart disease
• Endothelial lining


  Smooth inner wall of artery
• Atheroma deposited on endothelium

  Reduces available volume for blood flow
• Phospholipids


  A special type of lipid with one fatty acid tail replaced by a polar phosphate group