Intro

• The key biological molecules are carbohydrates, proteins, lipids and nucleic acids.
• The chemical elements that can be found in the key biological molecules are carbon, hydrogen, oxygen and nitrogen. Some also contain phosphorus or sulphur.
• Metabolism is the sum total of all biochemical reactions taking place in the cells of an organism.
• Catabolic reactions are reactions that break down larger molecules into smaller ones.
• Anabolic reactions are reactions that join smaller molecules together to form larger ones.
• Monomers are single small molecules. Examples are monosaccharides such as alpha glucose, amino acids or nucleotides.
• Polymers are large molecules made up of many similar monomers covalently bonded together. Examples are polysaccharides, polypeptides and proteins, or DNA and RNA.
• Condensation Reaction- the chemical reaction which combines biological monomers.

  • A new covalent bond is formed
  • A water molecule is released
  • A larger molecule is formed by joining smaller molecules.
• Hydrolysis reaction- splitting larger biological molecules to smaller ones

  • A covalent bond is broken
  • A molecule of water is used
  • Smaller molecules are formed.