Biology Paper 1

• Cells start off looking the same and then various different genes will be turned on and turned off, and that's when it will start to specialize, that's when differentiation will take place.
• The hierarchy is cells, tissues, organs, organ systems.
• Captions make revision easier
• No link between MMR vaccine and autism
• This is natural selection in action
• Penicillin has saved millions of lives
• Alexander Fleming discovered penicillin


  1928
• Before penicillin, people died of common things
• Penicillin was an accidental discovery
• Producing an uncontaminated bacterial culture

  1. Flame inoculation loop

  2. Open bottles near flame

  3. Transfer sample quickly

  4. Incubate at 37°C or 25°C
• Assume bacteria are pathogenic, work in a clean area
• Testing antibiotics/antiseptics on bacteria

  1. Label underside of agar plate

  2. Place filter paper disks

  3. Incubate at 25°C for 48 hours

  4. Measure clear zones