4 Bioenergetics

• Photosynthesis


  1. Plants harness the Sun's energy

  2. Make food
• Photosynthesis liberates oxygen which has built up over millions of years in the Earth's atmosphere
• Processes that use oxygen

  • Aerobic respiration (animals and plants)
  • Anaerobic respiration
• Aerobic respiration


  Process that transfers the energy the organism needs to perform its functions
• Anaerobic respiration


  Process that does not require oxygen to transfer energy
• During vigorous exercise


  The human body is unable to supply the cells with sufficient oxygen and it switches to anaerobic respiration
• Anaerobic respiration supplies energy but also causes the build-up of lactic acid in muscles which causes fatigue