B9 Respiration

• Respiration is used to:

  • Build up larger molecules from smaller ones (proteins from amino acids).
  • In animals, it’s used to allow the muscles to contract.
  • In mammals and birds, the energy is used to keep their body temperature steady in colder surroundings.
• Examples of Metabolic Reactions:

  • Conversion of glucose to starch, glycogen and cellulose.
  • Forming lipids from fatty acids and glycerol.
  • Using glucose and nitrate ions to form amino acids which are then built into proteins.
  • Reactions of photosynthesis
  • Breaking down excess proteins in the liver to form urea, which is excreted as urine by the kidneys.
• The Liver is used to:

  • Break down old red blood cells & alcohol
  • Store iron
  • Convert lactic acid to CO2 and H2O
  • Break down extra proteins to urea.
• Heart rate increases to get more blood, so more oxygen and glucose, go to the required muscle cells. This allows the cell to do more respiration to release more energy for muscle contractions. The increased heart rate also removes waste CO2.
• Breathing rate and depth/volume increase to get more oxygen into the blood. This is so the cells can do more respiration with oxygen and glucose, to release more energy for muscle contractions. An increased breathing rate and volume also removes waste CO2 because CO2 is a poisonous gas.
• Glycogen in your muscles is turned into glucose so more glucose can be transported around in your blood. This allows cells to do more respiration, with oxygen and glucose, to release more energy for muscle contractions. As more respiration happens, waste CO2 is also removed.
• The arteries supplying the muscles dilate to allow more blood to reach the muscle cells. This allows the muscle cell to do more respiration, with oxygen and glucose, to release more energy for muscle contractions because the blood carries around oxygen. As more respiration happens, waste CO2 is also removed.
• Respiration is the process of transferring energy from the breakdown of glucose and it goes on in every cell in your body continuously. It is exothermic.
• Aerobic Respiration is respiration with oxygen / in the presence of oxygen.

  Aerobic Respiration reactions mostly happen in the mitochondria.
• Anaerobic is respiration without oxygen. It is the incomplete breakdown of glucose, making lactic acid.

  Anaerobic respiration happens during vigorous exercise.

  It does not transfer nearly as much energy as aerobic respiration because the glucose isn’t fully oxidised.
• Plants and Yeast respire without oxygen too, but they produce ethanol and carbon dioxide rather than lactic acid. In yeast cells, this is called fermentation.
• Metabolism is the sum (total) of all the reactions that happen in a cell or the body.
• In a cell, there are lots of chemical reactions happening all the time, which are controlled by enzymes. Many of these reactions are linked together to form bigger reactions.
• An oxygen debt is the amount of extra oxygen your body needs to react with the build-up of lactic acid and remove it from the cells. Oxygen reacts with the lactic acid to form harmless CO2 and water.

  This means that you have to keep breathing hard for a while after you stop, to get more oxygen into your blood, which is transported to the muscle cells.

  The pulse and breathing stay high whilst there are high levels of lactic acid and CO2.

  The body can also transport the lactic acid to the liver to convert it back to glucose.