1.8 Inorganic ions

• iron ion

  • found in haemoglobin
  • Fe2+ is in the reaction centre of the heme group
  • where oxygen temporarily binds to iron ions
  • forming oxyhaemoglobin
  • and temporarily become Fe3+
• Phosphate ion

  • can be attached to other molecules as a phosphate group
  • in DNA enables nucleotides to join together as phosphodiester bonds resulting in the sugar phosphate backbone
  • used to produce ATP via phosphorylation of ADP
  • can phosphorylate other compounds to make them more reactive
  • part of the phospholipid which make up the cell membrane making it polar/ hydrophilic
• sodium ion

  • required for cotransport of glucose and amino acids
  • enables glucose and amino acids to move across the cell membrane
  • move into neurones to create an action potentials
  • affects osmosis as regulates water potential of cells
  • regulates osmotic pressure in plants
  • maintains pH of cells
• hydrogen ions

  • required to maintain pH levels in body
  • too much H+ to acidic- low pH
  • too little H+ to alkaline- high pH
  • ensures enzyme controlled reactions can take place
  • enzymes are all effected by pH
  • as causes ionic and hydrogen bonds to break in the tertiary structure, this changes shape of active site