How many molecules of ATP are required for gluconeogenesis?

In gluconeogenesis, the pathway that synthesizes glucose from non-carbohydrate precursors, a total of 6 high-energy phosphate bonds are consumed to produce one molecule of glucose. This process primarily occurs in the liver and to a lesser extent in the kidney.

The key steps in gluconeogenesis that require ATP are as follows:

1. Conversion of pyruvate to phosphoenolpyruvate (PEP) involves the fixation of ATP, utilizing two high-energy phosphate bonds. This reaction is catalyzed by pyruvate carboxylase and PEP carboxykinase.

2. Glycerol and lactate can also contribute to gluconeogenesis, but in these pathways, they lead to the use of other substrates which also consume ATP equivalents.

3. Additionally, during the conversion of 3-phosphoglycerate to glyceraldehyde-3-phosphate, ATP is again consumed.

In total, while gluconeogenesis consumes both ATP and GTP (which is equivalent to additional ATP in terms of energetic cost), the entire process is effectively seen as requiring 6 molecules of ATP when including these GTP equivalents in the overall account of energy costs.

Thus, the correct understanding of glucone