Gluconeogenesis

Question 1

Where does gluconeogenesis occur?

Answer 1

1. Liver (90%)
2. Kidney (10%)

in both mitochondria and cytosol

Question 2

What reactions in the body that occur in both cytosol and mitochondria

Answer 2

1. Heme synthesis
2. Urea cycle
3. Gluconeogenesis

Question 3

What are the substrates used for gluconeogenesis?

Answer 3

1. TCA intermediates (malate)
2. Lactate
3. Glycerol and propionylCoA
4. Gluconeogenic amino acids

Question 4

What are examples of your gluconeogenic amino acids?

Answer 4

1. Arginine (R)
2. Histidine (H)
3. Methionine (M)
4. Valine (V)
5. Alanine (A)
6. Asparagine (
7. Aspartate (D)
8. Cysteine (C)
9. Glutamate (E)
10. Glycine
11. Proline (P)
12. Serine (S)

Question 5

What is the rate limiting step in gluconeogenesis?

Answer 5

F1,6BP to F6P

via Fructose 1,6 bisphosphatase

Question 6

what is the first step of gluconeogenesis?

Answer 6

Pyruvate to oxaloacetate

via: pyruvate carboxylase

Question 7

What are the steps involved to convert pyruvate to Phosphoenolpyruvate

Answer 7

1. Pyruvate to oxaloacetate via pyruvate carboxylase

2. Oxaloacetate to phosphoenolpyruvate via PEP carboxykinase

Question 8

What enzyme is used to convert F1,6BP to F6P?

Answer 8

F1,6 BP

Question 9

What enzyme is used to convert G6P to glucose?

Answer 9

G6 phosphatase

Question 10

What are the coenzymes needed by pyruvate carboxylase?

Answer 10

1. Biotin

2. ATP

Question 11

In order to transport oxaloacetate out of the mitochondrion, it is reduced to?

Answer 11

malate

Question 12

What enzymes require biotin as cofactor?

Answer 12

1. Pyruvate carboxylase (pyruvate to oxaloacetate)
2. Acetyl CoA carboxylase (acetyl CoA to malonyl CoA)
3. Propionyl CoA carboxylase (Propionyl CoA to methylmalonyl CoA

Question 13

What step in gluconeogenesis requires GTP?

Answer 13

Oxaloacetate to phosphoenolpyruvate

via phosphoenolpyruvate carboxykinase

Question 14

What is the key enzyme that catalyzes the net transfer out of the citric acid cycle into gluconeogenesis?

Answer 14

Phosphoenolpyruvate carboxykinase

Question 15

What is the rate limiting step of gluconeogenesis?

Answer 15

F1,6BP to F6P via fructose 1,6 bisphosphatase

Question 16

What inhibits the conversion of F1,6BP to F6P?

Answer 16

1. Fructose 2,6 bisphosphate

Question 17

What step in gluconeogenesis is shared with glycogenolysis?

Answer 17

G6P to Glucose via glucose 6 phosphatase

Question 18

___ cycle is the formation of glucose from lactate

Answer 18

Cori Cycle

Question 19

What regulates gluconeogenesis?

Answer 19

1. Glucagon
2. Availability of gluconeogenic substrates
3. Allosteric activation of hepatic pyruvate carboxylase by acetyl CoA
4. Allosteric inhibition of F1,6BP by AMP

Question 20

What are the energy requirements of gluconeogenesis if from pyruvate?

Answer 20

1. Cleavage of 6 high-energy phosphate

2. Oxidation of 2 NADH

Question 21

The energy requirements of gluconeogenesis is derived from?

Answer 21

Oxidation of fatty acids

Question 22

[Clinical Correlates]

Glucosuria happens when the venous blood glucose concentration is

Answer 22

10.0 mmol/L (renal threshold)