Antibiotics

• What are antimicrobials?

  compounds that inhibit the growth of bacteria
• What are the different antimicrobials?

  • antiseptics: used on living tissue
  • disinfectants: used on non-living surfaces
  • antibiotics: a substance produced by a fungus, which diminishes the growth of bacteria
• What colour do gram positive bacteria stain?

  Purple
• What colour do gram negative bacteria stain?

  Red
• What is the structure of the cell wall of a gram negative bacteria?

  • layer of lipopolysaccharide
  • thinner layer of peptidoglycan (up to 10%)
• What is the structure of the cell wall of a gram positive bacteria?

  • no lipopolysaccharide
  • thicker layer of peptidoglycan (up to 90%)
• What is peptidoglycan also known as?

  Murein
• Peptidoglycan contains polysaccharides and short chains of amino acids
• Transpeptidase enzymes cross-link the polysaccharide molecules by attaching them to the side chains of amino acids. The cross links make the cell wall strong