Glucose Metabolism

Question 1

What is gluconeogenesis?

Answer 1

The reverse of glycolysis

Forming glucose from pyruvate

Question 2

What is the first step of gluconeogenesis?

Answer 2

Pyruvate is converted to oxaloacetate
By pyruvate carboxylase
CO2 addition
ATP converted to ADP

Question 3

What is the second step of gluconeogenesis?

Answer 3

Oxaloacetate is converted to phosphoenolpyruvate
By phosphoenolpyruvate carboxykinase
CO2 released
GTP converted to GDP

Question 4

What is the third step of gluconeogenesis?

Answer 4

Phosphoenolpyruvate is converted to fructose-1,6-biphosphate

Question 5

What is the fourth step of gluconeogenesis?

Answer 5

Fructose-1,6-biphosphate is converted to fructose-6-phosphate
By fructose-1,6-biphosphatase
Inorganic phosphate released

Question 6

What is the fifth step of gluconeogenesis?

Answer 6

Fructose-6-phosphate is converted to glucose-6-phosphate

Question 7

What is the sixth step of gluconeogenesis?

Answer 7

Glucose-6-phosphate is converted to glucose
By glucose-6-phosphatase
Inorganic phosphate is released

Question 8

What is Von Gierke’s disease?

Answer 8

Absence of glucose-6-phosphatase
Results in severe fasting hypoglycaemia
Large amounts of glycogen seen in liver

Question 9

What is the Cori cycle?

Answer 9

Exercising muscle converts glucose to lactate. The liver converts lactate to glucose and glucose returns to the muscle