Gluconeogenesis

Question 1

What is the function of gluconeogenesis?

Answer 1

Maintain blood glucose levels in fasting conditions

Question 2

Where is the location of gluconeogenesis?

Answer 2

Mitochondria, Cytosol, & ER lumen of Liver/Kidney

Question 3

Whta is the rate limiting enzyme of gluconogenesis?

Answer 3

Fructose 1,6-Bisphosphatase

Question 4

What is the net energy production of gluconeogenesis?

Answer 4

• -4 ATP
• -2 GTP
• -2 NADH

Question 5

What activates gluconeogenesis?

Answer 5

• Glucagon (Inc. CREB = Activates PEPCK gene expression)
• Corticosteroids (Activates PEPCK gene expression)
• Adrenaline

Question 6

What inhibits gluconeogenesis?

Answer 6

• Insulin
• F-2,6-BP
• AMPK

Question 7

What occurs in the fed state of gluconeogenesis?

Answer 7

• Increase insulin
• Decrease glucagon
• Inhibit gluconeogenesis

Question 8

What occurs in the fasted state of gluconeogenesis?

Answer 8

• Decrease insulin
• Increase glucagon
• Activate gluconeogenesis

Question 9

What occurs in the stressed state of gluconeogenesis?

Answer 9

• Increase corticosteroids
• Increase adrenaline
• Activate gluconeogenesis

Question 10

What is type 1 & type 2 diabetes?

Answer 10

• type 1 -> lack of insulin production
• type 2 -> insulin resistance due to overstimulation

Question 11

What is the treatment for type 1 & 2 diabetes?

Answer 11

Metformin -> Metformin stimulates liver AMP-activated protein kinase (AMPK) -> AMPK inhibits gluconeogenesis despite lack of insulin

Question 12

What is the location of glycogen metabolism?

Answer 12

liver & muscle

Question 13

What is the rate limiting enzyme of glycogen metabolism?

Answer 13

• Glycogen Synthase -> anabolism
• Glycogen Phosphorylase -> catabolism

Question 14

What are the 3 fates of G-6-P?

Answer 14

1. -4 ATPGlycolysis into pyruvate
2. Gluconeogenesis into glucose (only in liver)
3. PPP into Ribose & NADPH

Question 15

What stimulates glycogen synthesis in the liver?

Answer 15

glucose

Question 16

What stimulates glycogen synthesis in the muscle?

Answer 16

insulin

Question 17

What stimulates glycogen breakdown in the liver?

Answer 17

glucagon & beta-agonists

Question 18

What stimulates glycogen breakdown in the muscle?

Answer 18

beta- agonists

Question 19

What are the steps of the breakdown of glycogen in the liver?

Answer 19

1. Glucagon & Epi stimulate adenylyl cyclase to make cAMP
2. cAMP activates breakdown of glycogen
3. G-6-P can be broken down into pyruvate and turned into fat OR G-6-P can undergo gluconeogenesis into glucose (since we’re in the liver)
4. Blood glucose levels increase

Question 20

What are the steps of the breakdown of glycogen in the muscle?

Answer 20

1. Epi stimulates adenylyl cyclase to make cAMP
2. cAMP activates breakdown of glycogen
3. G-6-P has to be broken down into pyruvate
4. Pyruvate is converted into lactate

Question 21

What glycogen associated diseases are considered glycogen synthesis diseases?

Answer 21

Anderson -> glycogen branching enzyme deficiency

Question 22

What glycogen associated diseases are considered glycogenolysis diseases?

Answer 22

• von Gierke’s -> glucose-6-phosphate deficiency
• Cori’s -> glycogen debranching enzyme
• McArdle -> glycogen phosphorylase deficiency