respiration

• respiration is the process of transferring energy from the breakdown of glucose
• organisms use energy from resp.:

  • to build larger molecules from smaller ones (amino acids to proteins)
  • to contract muscles
  • to keep body temp steady
• metabolism is all the chem reactions in an organism
• chemical reactions are controlled by enzymes
• in plants glucose molecules join to make starch and cellulose, and glycogen in animals
• lipid molecules are made from 1 glycerol and 3 fatty acids
• glucose is combined with nitrate ions to make amino acids which make proteins
• excess protein is broken down to produce urea, which is excreted in urine
• aerobic respiration is the most efficient way to transfer energy from glucose
• reactions in aerobic resp happen inside mitochondria
• aerobic:

  glucose + oxygen -> carbon dioxide + water
• anaerobic resp is for when the body can’t supply enough oxygen to muscles
• anaerobic resp is the incomplete breakdown of glucose, which makes lactic acid
• anaerobic resp:

  glucose -> lactic acid
• anaerobic resp transfers less energy as aerobic because glucose isn’t fully oxidised
• in plants and yeast cells, ethanol and co2 are produced instead of lactic acid in anaerobic resp
• anaerobic in plants and yeast:

  glucose -> ethanol + carbon dioxide
• anaerobic resp in yeast is fermentation
• when you exercise, muscles need more energy because they are contracting more often. this energy comes from increased resp
• inc in resp means more oxygen is needed, so breathing rate and breath volume increase. heart rate increases to get oxygenated blood around faster. this also removes co2 faster
• oxygen debt is the amount of extra oxygen your body needs to react to the buildup of lactic acid and remove it from cells. oxygen reacts with lactic acid to form safe co2 and water
• to pay oxygen debt, you keep breathing hard and keep a high pulse and breathing rate.
• lactic acid is transported to the liver where it is converted to glucose