Inorganic ions

• • Haemoglobin is a large protein that carries oxygen around the body, in the red blood cells.
  • It’s made up of four different polypeptide chains, each with an iron ion in the centre.
  • It’s the Fe2+ that actually binds to the oxygen in haemoglobin — so it’s a pretty key component.
  • When oxygen is bound, the Fe 2+ ion temporarily becomes an Fe3+ ion, until oxygen is released.
• Hydrogen ions

  • pH is calculated based on the concentration of hydrogen ions (H +) in the environment.
  • The more H+ present, the lower the pH (and the more acidic the environment).
  • Enzyme-controlled reactions are all affected by pH
• Sodium ions

  Glucose and amino acids need a bit of help crossing cell membranes.

  A molecule of glucose or an amino acid can be transported into a cell (across the cell-surface membrane) alongside sodium ions (Na+).

  This is known as co-transport.
• Phosphate ions

  • When a phosphate ion is attached to another molecule, it’s known as a phosphate group. DNA, RNA and ATP all contain phosphate groups.
  • It’s the bonds between phosphate groups that store energy in ATP
  • The phosphate groups in DNA and RNA allow nucleotides to join up to form the polynucleotides
• Iron ion is polar therefore is able to bind to oxygen