1.1 - Biological compounds

• Inorganic ions required for plant growth and development


  • Nitrate ions
  • Calcium ions
  • Phosphate ions
  • Magnesium ions
  • Iron ions
• Nitrate ions


  Required to make DNA and amino acids
• Calcium ions


  Needed to form calcium pectate for the middle lamellae
• Phosphate ions


  Required to make ADP and ATP
• Magnesium ions


  Needed to produce chlorophyll
• Iron ions


  A component of haemoglobin which is an oxygen carrying molecule in red blood cells
• Water


  • Polar molecule due to uneven distribution of charge
  • Metabolite in metabolic reactions such as condensation and hydrolysis
  • Solvent in which many metabolic reactions occur
  • High heat specific capacity minimising temperature fluctuations in living things
  • Relatively large latent heat of vaporisation providing a cooling effect
  • Strong cohesion between molecules enabling effective transport in tube like transport cells
• Types of saccharides


  • Monosaccharides
  • Disaccharides
  • Polysaccharides
• Glycosidic bonds


  Formed in condensation reactions to join monosaccharides to form disaccharides and polysaccharides
• Monosaccharides


  Small organic molecules used as building blocks of complex carbohydrates
• Monosaccharides


  • Glyceraldehyde
  • Ribose
  • Glucose
• Glucose


  Monosaccharide containing six carbon atoms, main substrate for respiration
• Disaccharides


  • Maltose
  • Sucrose
  • Lactose
• Maltose


  Disaccharide formed by condensation of two glucose molecules
• Sucrose


  Disaccharide formed by condensation of glucose and fructose
• Lactose


  Disaccharide formed by condensation of glucose and galactose
• Polysaccharides


  • Glycogen
  • Starch
  • Cellulose
• Glycogen


  Main energy storage molecule in animals, formed from many molecules of alpha glucose joined by 1,4 and 1,6 glycosidic bonds, has a large number of side branches
• Starch


  Energy storage molecule in plants, mixture of amylose and amylopectin
• Amylose


  Unbranched chain of glucose molecules joined by 1,4 glycosidic bonds, coiled and compact
• Amylopectin


  Branched and made up of glucose molecules joined by 1,4 and 1,6 glycosidic bonds, rapidly digested by enzymes
• Cellulose


  Component of cell walls in plants, composed of long, unbranched chains of beta glucose joined by glycosidic bonds, microfibrils provide structural support
• Chitin


  Polysaccharide made of chains of beta glucose monomers with amino acid side chains, lightweight but strong, forms exoskeletons of insects
• Types of lipids

  • Saturated lipids
  • Unsaturated lipids
• Saturated lipids


  Don't contain any carbon-carbon double bonds, found in animal fats, can increase cholesterol levels

  
• Unsaturated lipids


  Contain carbon-carbon double bonds, found in plants, provide essential fatty acids

  
• Triglycerides


  Lipids made of one molecule of glycerol and three fatty acids joined by ester bonds, used as energy reserves

  
• Phospholipids


  One of the fatty acids of a triglyceride is substituted by a phosphate-containing group, form micelles when in contact with water

  
• Amino acids


  Monomers from which proteins are made, contain an amino group, carboxylic acid group and a variable R group
• Peptide bonds


  Formed in condensation reactions to join amino acids
• Primary structure of proteins

  Order and number of amino acids
• Secondary structure of proteins


  Shape of the chain of amino acids, either alpha helix or beta pleated sheet, determined by bonding
• Tertiary structure of proteins


  3D shape of the protein, can be globular or fibrous
• Collagen


  Fibrous protein of great strength due to presence of hydrogen and covalent bonds, forms structure of bones, cartilage, connective tissue and tendons
• Haemoglobin


  Water soluble globular protein which consists of two beta polypeptide chains and a haem group, carries oxygen in the blood