B9

• respiration(where)


  takes place in the mitochondria which is found more in the heart because the heart needs more energy to pump blood
• respiration


  also called cellular respiration and is an exothermic reaction
• aerobic respiration(organisms)

  an organism will recieve all the energy it needs for living processes as a result of the energy transferred from respiration
• aerobic respiration (glucose)

  glucose is oxidised by oxygen to transfer the energy the organism needs to perform it's function
• aerobic respiration(release)

  releases large amounts of energy from each glucose molecule
• aerobic respiration (WE)

  glucose + oxygen - carbon dioxide + water + lot's of energy
• aerobic respiration (CE)


  C6H12O6 + 6O2 → 6CO2 + 6H2O
• anaerobic respiration


  can transfer energy without oxygen
• anaerobic respiration (hard excercise)

  during hard excercise, muscle cells are respiring so fast that the blood cannot transport enough oxygen to meet their needs
• anaerobic respiration(glucose)


  glucose is not completely broken down to carbon dioxide and water, so less energy is transferred
• anaerobic respiration(end product)

  an end product called lactic acid is formed. this builds up in the muscle cells
• anaerobic respiration ( where else does it occur)

  also occurs in plant and yeast cells.
• anaerobic respiration

  • glucose - ethanol + carbon dioxide
  • anaerobic respiration in yeast cells is called fermentation
  • this process is economically important in the manufacture of alcoholic drinks and bread
• anaerobic respiration 


  glucose - lactic acid + little energy
• what happens during excercise?

  1. your heart beats faster
  2. your oxygen is pumped around your body through the blood and through the muscle cells
  3. more glucose is burnt
  4. more aerobic respiration in the mitochondria
  5. more energy is released
• what happens when anaerobic respiration takes place in muscle cells?

  1. lactic acid builds up in the muscle cells during excercise
  2. blood flows through the muscle cells and transports the latic acid to the liver
  3. the liver oxideses the lactic acid and converts it back to glucose
  4. glucose is used in aerobic respiration or it is converted to glycogen and stored in the liver for later use
• oxygen debt 


  the amount of energy needed to convert lactic acid to carbon dioxide
• why do living organisms need energy?

  • for movement - to enable muscles to contact
  • to keep warm - to keep a steady temperature in a cold environment
  • for chemical reactions - to build larger molecules from smaller ones
• metabolim

  the sum of all reactions in a cell or body which are controlled by enzymes
• examples of metabolism

  • respiration to form energy
  • glucose converted to starch
  • glucose and nitrate ions from the soil form amino acids
  • glucose converted to cellulose to strengthen cell walls
  • glucose converted to glycogen in animal cells for storage
  • formation of lipids from a molecule of glycerol and three molecules of fatty acids
  • breakdown of proteins to form urea for excretion