Glycolysis

• Glycolysis

  • Occurs in cytoplasm

  • Anaerobic process (doesn’t require oxygen); the first stage of aerobic and anaerobic respiration.

  1. Phosphorylation of glucose to glucose phosphate

  • Using the inorganic phosphates from 2 ATP

  2. Hydrolysed to 2 X triose phosphate

  3. 2 X Triose phosphate oxidised to 2 X pyruvate

  • 2 NAD reduced (collects hydrogen ions)

  • 4 ATP regenerated

  • 4 gained – 2 used = net production of 2 ATP

  
• After glycolysis if no oxygen present (anaerobic respiration)

  1. Pyruvate converted to lactate (animal cells, some bacteria) or ethanol (plants, yeast)

  2. Oxidising reduced NAD NAD regenerated

  3. So glycolysis can continue which needs / uses NAD

  • Note: Some energy still in lactate (incomplete breakdown of glucose)

  • Anaerobic respiration is much less efficient than aerobic respiration; the ATP yield is lower. The majority of ATP is formed in oxidative phosphorylation

  
• Pyruvate actively transported into the mitochondrial matrix

  • Stages of aerobic respiration:

  1. Glycolysis

  2. Link reaction

  3. Krebs cycle

  4. Oxidative phosphorylation