cellular respiration

• what is the equation for aerobic respiration


  $C6H12O6+$$6O2--->6CO2+$$6H2O$
• what is cellular respiration 


  the biochemical process which takes place within the bodys cells to produce energy by the chemical breakdown of glucose
• how many stages are present within aerobic respiration

  3

  glycolysis and the link reaction

  krebs cycle

  electron transport chain
• where does aerobic respiration take place

  mitochondria

  in the matrix-krebs cycle
• describe glycolysis 


  Glucose is phosphorylated twice to make a 6C sugar phosphate. 2

  ATPs are used to supply the P groups. This makes the glucose more

  reactive

  2.The 6C sugar phosphate breaks down to form 2, 3-carbon sugar

  phosphates, called triose phosphates (TP).

  3.Hydrogen is removed from each of the 2 TP molecules. The

  hydrogens are passed to 2 NADs (the NADs are reduced forming

  NADH).

  Net Gain = 2 ATP produced directly
• describe the link reaction

  the pyruvate made in glycolysis combines with co-enzyme A to form aceytl-coA.
• describe the krebs reaction

  Each acetylCoA (2C) combines with an oxaloacetic acid (4C) to make a 6C compound (citric acid/ citrate).

  2.In a series of steps, for each 3C compound,

  2 CO2

  molecules are released,

  3 NAD molecules are reduced,

  1 FAD molecules is reduced,

  1 ATP molecule is made directly.

  3.The 4C compound is regenerated (by the removal of the 2 Cs in 2 CO2

  molecules) so that the cycle can begin again with more molecules

  of acetylCoA.
• describe the electron transport chain

  • Hydrogen atoms are donated from NADH and FADH2 which split into H+ and electrons
  • which enter the ETC and release energy as they move through the ETC releasing energy
  • which is used to transport protons across the matrix to the intermembrane space where a concentration gradient is establised
  • The movement of protons down their concentration gradient provides energy for ATP synthesis
  • oxygen acts as the 'final electron acceptor' and combines with protons and electrons at the end of the electron transport chain to form water
• how are the protons returned back to the matrix

  vis facilitated diffusion
• all togehter how much ATP is produced

  38

  2 in glycolysis 6 in the link reaction

  15 in the krebs and ETC. krebs cycle runs twice so 15 x 2 =30
• what is anaerobic respiration

  When there is no oxygen to act as a final acceptor, the electron transport

  chain and Krebs cycle do not function.

  No oxygen to accept electrons from NADH + H+ → no Krebs cycle or ETC

  ● NADH + H+ reduces pyruvate to produce

  Lactate (C3) in animal cells → can be re-oxidised

  ● Regenerates NAD

  ● NAD can be re-used to allow glycolysis to continue

  ● Can still form ATP/ release energy when oxygen is in short supply
• what is an oxygen debt

  Anaerobic respiration will yield only the ATPs made in glycolysis, i.e. 2 molecules of ATP.

  Compared to aerobic respiration (38 ATP

  ● Eventually lactic acid builds up.

  The formation of lactic acid can be reversed but needs oxygen.

  ● When oxygen becomes available again, it is converted into CO2 and water in aerobic

  respiration.

  That is why anaerobic respiration cannot carry on indefinitely. Anaerobic respiration builds up

  an oxygen debt and that has to paid off