B-Oxidation And Ketogenesis Of Lipids

Question 1

How is HSL activated for lipid mobilization?

Answer 1

1. Epinephrine binds to receptor
2. ATP converted to cAMP via adenylate cyclase
3. cAMP converted to protein kinase
4. Protein kinase phosphorylates HSL
5. Active HSL hydrolyzes TAGs
6. Phosphatase dephosphorylates HSL
7. Other lipases remove FAs

Question 2

What happens to glycerol after lipid mobilization?

Answer 2

1. Adipocytes lack glycol kinase
2. Transport glycerol to the liver using aquaporin
3. Glycerol is phosphorylated in the liver to make new TAGs or converted to DHAP for glycolysis

Question 3

What happens to FFAs after lipid mobilization?

Answer 3

1. FFAs move through adipocytes and bind to albumin
2. FFAs transported to peripheral tissues
3. FFAs converted to acetyl CoA derivatives for oxidation

Question 4

How are FFAs oxidized?

Answer 4

2 carbon fragments removed in the mitochondria

Question 5

Where are long chain fatty acids transported to?

Answer 5

The mitochondria
Converted to acetyl CoA derivatives

Question 6

How are long chain fatty acids transported?

Answer 6

LCFA transferred by Carnitine shuttle

Question 7

How is Carnitine inhibited?

Answer 7

Malonyl CoA prevents palmitate from entering mitochondria therefor stopping reaction from taking place

Question 8

Where does Carnitine come from?

Answer 8

The diet
It is then synthesized from lysine and methionine

Question 9

What are the four b oxidation reactions?

Answer 9

1. Oxidation of FADH2
2. Hydration
3. Oxidation of NADH
4. Thiolytic cleavage of acetyl CoA

Question 10

What are the three types of ketones?

Answer 10

Acetoacetate, 3-hydroxybutyrate, and acetone

Question 11

How is acetyl CoA converted to ketones?

Answer 11

1. Thiolase converts 2 acetyl CoA into acetoacetyl CoA
2. acetoacetyl CoA converted into HMG CoA
   3.HMG CoA converted to acetoacetate
3. Acetone converted to 3-hydroxybutyrate