Respiration and Exercise

• involves reactions catalysed by enzymes 
• releases the energy the cells need to do everything 
• process of releasing energy from the breakdown of glucose which goes on in every cell
• releases energy to..
  • build large molecules from small ones-proteins from amino acids 
  • allow muscle to contract (animals) 
  • keep body temperature steady (mammals) 
  • turn sugars, nitrates and other nutrients into amino acids for making protiens (plants)

·   'in the presence of oxygen'

·    efficient way to release energy from glucose 

·    goes on all the time 

·     happens inside mitochondria

·  Glucose -------> carbon dioxide + water (+ energy) 

• 'without oxygen' 
• vigorous exercise- body cant get enough oxygen for aerobic respiration 
• incomplete breakdown of glucose, produces lactic acid 
• lactic acid causes pain in muscles & muscle fatigue 
• not as much energy as aerobic 
• oxygen debt- repay the oxygen that your muscles didn't get, break down the lactic acid 
• keep breathing heavily after you stop exercising to pay back debt 

• Glucose ----------> lactic acid (+ energy) 

• muscle cells use oxygen to release energy from glucose which is used to contract muscles 
• physical activity...
  • increases breathing rate- to meet demand for oxygen 
  • increases heart rate- to pump the blood quicker to get the oxygen to the muscle cells
• some glucose- stored as glycogen
• each muscle cell has it own store 
• during exercise-glycogen converted back to glucose to provide more energy