C12: respiration

• respiration - a chemical process that involves the breakdown of nutrient molecules (specifically glucose) in order to release the energy stored within the bonds of these molecules
• less energy released anaerobically
• most aerobic respiration take place in the mitochondria
• uses of energy in living organisms:

  • muscle contraction
  • protein synthesis
  • cell division
  • growth
  • active transport across cell membranes
  • generation of nerve impulses
  • maintaining constant internal body temperature
• aerobic respiration word equation:

  glucose + oxygen -> water + energy + carbon dioxide
• aerobic respiration balanced equation:

  C6H12O6 + 6O2 -> 6H2O + 6CO2
• anaerobic respiration yeast word equation:

  glucose -> carbon dioxide + ethanol
• yeast balanced equation:

  C6H12O6 -> CO2 + 2C2H5OH
• anaerobic equation animal equation:

  glucose -> lactic acid
• • anaerobic respiration mainly takes place in muscles cells during vigorous exercise
  • because muscles have a higher demand for energy
  • our bodies only produce enough oxygen to our muscles cells for aerobic respiration
  • some glucose is broken down without oxygen, producing lactic acid instead
• oxygen debt

  • lactic acid builds up in muscle cells and lowers the pH of the cells
  • this could cause the enzymes in the cells to denature, so it needs to be removed
  • cells excrete lactic acid into the blood
  • the blood passes through the liver and lactic acid goes into the liver cells to get oxidised
  • waste products of lactic acid oxidation: carbon dioxide & water
• repaying oxygen debt

  • transport lactic acid from muscles to liver and continue to get larger amounts of oxygen into the blood to oxidise the lactic acid