1. Section A: Exercise and Sport Physiology 3. ATP resynthesis

2. Syllabus Knowledge of the three energy systems – ATP/PC (alactic) – Lactic acid system – Aerobic system Detail required to include the type of reaction (aerobic or anaerobic), the chemical or food fuel used, the specific site of the reaction, the controlling enzyme, energy yield, specific stages within a system, and the by-products produced

3. ATP-PC System ADVANTAGES PC readily available source of energy Fast reaction No fatiguing by-products Recovery time is quick DISADVANTAGES 1 PC resynthesises 1 ATP Last for up to 10 seconds

4. Breakdown of PC coupled to ATP resynthesis

5. Lactic Acid System ADVANTAGES Resynthesises more ATP than previous system Less reactions than Aerobic so faster Can work aerobically and anaerobically Provides energy between 10 seconds and 3 minutes DISADVANTAGES Not as fast as ATP-PC Produces lactic acid Reduces pH Muscle fatigue and pain

6. Aerobic System ADVANTAGES Large energy stores Efficient and large amount of ATP resynthesis Lengthy duration: 3 min to 1 hour No fatiguing by-products FFAs produce more Acetyl CoA and therefore more energy than glucose DISADVANTAGES Requires more oxygen supply More complex series of reactions Cannot resynthesise ATP from start due to delay

7. Energy Continuum