Question
Which of the following enzymes are involved in gluconeogenesis?
A. Hexokinase
B. PEPCK (Phosphoenolpyruvate carboxykinase)
C. Pyruvate carboxylase
D. Pyruvate kinase
Choose the correct options:
| A. |
A, B and D
|
| B. |
B,C & D
|
| C. |
B and C
|
| D. |
A,B,C,D
|
Show Answer
|
Correct Answer » C
Explanation
|
|
Gluconeogenesis is the synthesis of glucose from non-carbohydrate precursors such as:
- Lactate
- Alanine and other glucogenic amino acids
- Glycerol
- Propionate
Major Sites
- Liver (primary site)
- Kidney cortex (during prolonged fasting)
Purpose
Maintains blood glucose during:
- Fasting
- Starvation
- Prolonged exercise
Key Enzymes of Gluconeogenesis
Gluconeogenesis bypasses the three irreversible steps of glycolysis using four unique enzymes:
| Irreversible Glycolytic Enzyme |
Gluconeogenic Bypass Enzyme |
| Pyruvate kinase |
Pyruvate carboxylase + PEPCK |
| Phosphofructokinase-1 (PFK-1) |
Fructose-1,6-bisphosphatase |
| Hexokinase/Glucokinase |
Glucose-6-phosphatase |
