Respiration

• Cellular respiration is an exothermic reaction that occurs continuously in the mitochondria of living cells to release energy from glucose.
• Organisms need energy for:

  Chemical reactions to build larger molecules.

  Muscle contraction for movement.

  Keeping warm.
• Aerobic respiration uses oxygen while anaerobic respiration does not.
• The word equation for aerobic respiration:

  Glucose + Oxygen -> Carbon Dioxide + Water
• Symbol equation for aerobic respiration:

  C6H12O6 + 6O2 -> 6CO2 +6H2O
• Aerobic respiration releases more energy per glucose molecule because oxidation of glucose is complete in aerobic respiration and incomplete in anaerobic respiration.
• Fermentation is the anaerobic respiration in yeast cells.
• The word equation for anaerobic respiration in plant and yeast cells:

  Glucose -> Ethanol + Carbon Dioxide
• The body supplies the muscles with more oxygenated blood during exercise by increasing heart rate, breathing rate and breath volume.
• During anaerobic respiration, lactic acid builds up in the muscles.
• During long periods of activity, muscles become fatigued and stop contracting efficiently.
• Oxygen debt is the amount of oxygen the body needs after exercise to react with the accumulated lactic acid and remove it from cells.
• Lactic acid removal from the body:

  Lactic acid in muscles -> blood transports to the liver -> lactic acid converted back to glucose.
• Metabolism is the sum of all the reactions in a cell or the body.
• The word equation for anaerobic respiration:

  Glucose -> Lactic acid