Final answer:
The enzymes pyruvate carboxylase and phosphoenolpyruvate carboxykinase replace pyruvate kinase in gluconeogenesis, reversing the final step of glycolysis and leading to glucose synthesis.
Step-by-step explanation:
The steps that replace pyruvate kinase in gluconeogenesis involve converting pyruvate into oxaloacetate and then into phosphoenolpyruvate (PEP) through the action of two key enzymes: pyruvate carboxylase and phosphoenolpyruvate carboxykinase (PEPCK). This conversion reverses the final step of glycolysis, allowing for the synthesis of glucose from non-carbohydrate precursors. Other important enzymatic changes include using glucose-6-phosphatase instead of hexokinase, and fructose-1,6-bisphosphatase instead of phosphofructokinase-1. These enzymatic swaps are crucial for the cell to independently regulate glycolysis and gluconeogenesis, thus maintaining glucose homeostasis.