Gluconeogenesis Is Energetically Expensive but Essential

The sum of the biosynthetic reactions leading from pyruvate to free blood glucose (Table 14-3) is

For each molecule of glucose formed from pyruvate, six high-energy phosphate groups are required, four from ATP and two from GTP. In addition, two molecules of NADH are required for the reduction of two molecules of 1,3-bisphosphoglycerate. Clearly, Equation 14-9 is not simply the reverse of the equation for conversion of glucose to pyruvate by glycolysis, which requires only two molecules of ATP:

The synthesis of glucose from pyruvate is a relatively expensive process. Much of this high energy cost is necessary to ensure the irreversibility of gluconeogenesis. Under intracellular conditions, the overall free-energy change of glycolysis is at least —63 kJ/mol. Under the same conditions the overall AG of gluconeogenesis is — 16 kJ/mol. Thus both glycolysis and gluconeogenesis are essentially irreversible processes in cells.

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Responses

  • Hamish Martin
    Why is gluconeogenesis expensive?
    8 years ago
  • rosarmosario sagese
    Why is glucose energetically expensive?
    2 years ago
  • Taija
    Why is gluconeogenesis said to be energetically expensive, but essential?
    2 years ago
  • esko
    Why gluconeogenesis is an expensive process?
    2 years ago
  • Callisto
    Why is gluconeogenesis more expensive than glycolysis?
    1 year ago
  • brad russell
    Why is gluconeogenesis referred to as an expensive pathway?
    1 year ago
  • luciano
    Why is gluconeogenesis considered an expensive pathway?
    1 year ago
  • eeva
    Why is gluconeogenesis very essential despite being energetically expensive biochemistry explain?
    1 year ago
  • Daisy
    Why is gluneogenesis very essential despite being energetically expensive?
    1 year ago
  • silvestro
    Why gloconeogenesis is expensive?
    1 year ago
  • edward
    Why is glycolysis energetically expensive?
    1 year ago
  • Simret
    Is gluconeogeneis expensice?
    6 months ago
  • denese
    Why is glyconeogenesis energetically expensive but essential?
    1 month ago
  • bilba
    Why is gluconeogenesis very essential despite being energetically exoensive?
    4 days ago

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