12 Glycolysis

  • Created by: lee8444
  • Created on: 15-03-20 13:41

4 stages of glycolysis

1) Phosphorylation of glucose to glucose phosphate

  • Glucose is made more reactive
  • Addition of two phosphate molecules
  • Requires 2 ATP molecules (become ADP)
  • Lowers the activation energy for enzyme-controlled reactions

2) Splitting of phosphorylated glucose

  • Each glucose is split into two 3-carbon molecules (triose phosphate)

3) Oxidation of triose phosphate

  • Hydrogen is removed from each triose phosphate
  • Transferred to NAD turning it into reduced NAD

4) The production of ATP

  • Enzyme-controlled reactions convert each triose phosphate into pyruvate
  • Per reaction, 2 ATP are produced, 4 per glucose
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Energy yields from glycolysis

  • In total per glucose:
    • two molecules of ATP - 4 are produced but two are needed for the phosphorylation of glucose
    • two molecules of reduced NAD - have the potential to provide more energy to produce ATP - oxidative phosphorylation
    • two molecules of pyruvate
  • Universal for every living organism
  • Indirect evidence for evolution
  • Happens in the cytoplasm - doesn't require membrane-bound organelles
  • Doesn't require oxygen
  • Can be converted into ethanol or lactate - anaerobic respiration
  • This is necessary to re-oxidise the NAD for more glycolysis
  • Anaerobic respiration only yields a small amount of energy compared to aerobic respiration
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