Metabolism

• Metabolism is all of the chemical reactions in an organism
• In some reactions, larger molecules are made from smaller ones:

  • Glucose molecules joined together to form starch, glycogen and cellulose
  • Lipid molecules are each made from one molecule of glycerol and three fatty acids
  • Glucose is combined with nitrate ions to make amino acids, which are then made into proteins
• Larger molecules are broken down into smaller ones:

  • Glucose is broken down by respiration, this transfers energy to power all the reactions in the body
  • Excess protein is broken down in a reaction to produce urea, this is then exctreted in urine.