Question

Gluconeogenesis would most likely be allosterically activated simultaneously along with which other metabolic process?

1. glycolysis

2. glycogen synthesis

3. pentose phosphate pathway

4. citrate cycle

5. calvin cycle

Answer 1

glycogen synthesis

• Gluconeogenesis proceeds in the liver and kidney.
• Together with glycogen degradation, gluconeogenesis ensures stable blood glucose levels between meals.
• Just as in gluconeogenesis, the cell has a separate mechanism for glycogen synthesis that is distinct from glycogen breakdown.
• This process allows cell to separately control the reactions, avoiding futile cycles, and enabling a process to occur efficiently (synthesis of glycogen) that would not occur if it were simply the reversal of glycogen breakdown.
• Synthesis of glycogen starts with G1P, which is converted to an 'activated' intermediate, UDP-glucose. This activated intermediate is what 'adds' the glucose to the growing glycogen chain.
• Once the glucose is added to glycogen, the glycogen molecule may need to be rearranged to make it available for metabolism.
• Regulation is complex, occurring both allosterically and via hormone-receptor controlled events that result in protein phosphorylation or dephosphorylation.