Final answer:
The two enzymes of highly unfavorable reverse reactions of glycolysis and their replacements for gluconeogenesis are pyruvate carboxylase (or carboxykinase) and phosphoenol pyruvate carboxykinase. These enzymes play a crucial role in converting pyruvate to oxaloacetate and oxaloacetate to phosphoenolpyruvate (PEP) in the process of gluconeogenesis.
Step-by-step explanation:
The two enzymes of highly unfavorable reverse reactions of glycolysis and their replacements for gluconeogenesis are:
- Pyruvate carboxylase (or carboxykinase): This enzyme converts pyruvate to oxaloacetate in gluconeogenesis.
- Phosphoenol pyruvate carboxykinase: This enzyme converts oxaloacetate to phosphoenolpyruvate (PEP) in gluconeogenesis.
In the process of gluconeogenesis, the enzyme hexokinase in glycolysis is replaced by glucose-6-phosphatase, and the enzyme phosphofructokinase-1 is replaced by fructose-1,6-bisphosphatase. These replacements help regulate glycolysis and gluconeogenesis independently of each other.