Gluconeogenesis

Question 0

Production of glucose from the ff intermediates:

1. Intermediates of glycolysis and the TCA
2. Glycerol from triacylglycerols
3. Lactate through the Cori cycle
4. Carbon skeletons (a-Ketoacids) of glucogenic amino

Answer 0

Gluconeogenesis

Question 1

Where does it occur?

Answer 1

Occurs in the liver (90%) and the kidney (10%)

During prolonged fasting, the kidneys contribute as much as 40%

Occurs in both mitochondria and cytoplasm

Question 2

What is the substrate?

Answer 2

Pyruvate

Question 3

What is the product?

Answer 3

Glucose

Question 4

Which step is rate-limiting?

Answer 4

Reaction: Fructose 1,6-biphosphate ➡️ Fructose 6-phosphate

Enzyme: Fructose 1,6-biphosphate

Question 5

Conversion of lactate to glucose

Lactate generated during anaerobic metabolism

Lactate brought to the liver ➡️ converted to glucose via hepatic gluconeogenesis

Glucose brought back to muscles and RBC

Energy expense: 4 ATP molecules

Answer 5

Cori cycle

Question 6

Important steps in gluconeogenesis

Answer 6

Step 10: Pyruvate ➡️ OAA ➡️ PEP

Step 3: Fructose-1,6-biphosphatase ➡️ Fructose-6-phosphate

Step 1: Glucose-6-phosphate ➡️ Glucose