Respiration – S3 Biology Notes

These Senior 3 Biology notes cover cellular respiration. They explain how cells break down food to release energy as ATP and list the ways organisms use that energy. The notes compare aerobic and anaerobic respiration, giving word and chemical equations for each. Topics include lactic acid build-up in muscles, oxygen debt, and alcohol fermentation by yeast. Laboratory experiments show that respiring organisms give off carbon dioxide and heat and use up oxygen, and one experiment measures the rate of respiration. Commercial uses of anaerobic respiration are listed. Tables compare aerobic with anaerobic respiration and respiration with photosynthesis. The notes end with a graph-plotting task on lactic acid levels and short revision questions.