3. Lipids & Ketone bodies Flashcards
Are lipids more or less reduced than carbohydrates?
More reduced - produce more energy
What are the 3 classes of lipids?
- FA derivatives - FA, TAG, phospholipids
- HMG derivatives - cholesterol, cholesterol esters, ketone bodies
- Vitamines - A,D,E, K
How are TAGs stored?
Anhydrous form as lipid droplets in adipose tissue
What triggers FA release from adipose tissue?
Low plasma [glucose] means that less glycerol-1-phosphate is produced in adipose cells, causing FA to be released into the circulation.
What are the 3 steps in FA metabolism in target tissues?
- Activation in cytoplasm
- Carnitine shuttle transport into IMM
- Beta-oxidation - C2 removed
What enzyme is responsible for FA oxidation?
Fatty acyl CoA synthase
What controls the rate of FA oxidation?
Carnitine shuttle, inhibited by Malonyl CoA
In beta oxidation, what are the intermediates linked to?
CoA - leave as Acetyl CoA
What is the fate of Acetyl CoA from beta oxidation?
TCA cycle to provide energy
Which tissues can beta oxidation occur in?
Most tissues with mitochronidria - Not brain, RBC or WBC
Can beta oxidation occur without O2?
No - needs NAD+ and FAD
What is the fate of glycerol released from adipose tissue?
transported back to liver, into glycerol phosphate which can enter glycolysis as DHAP or TAG synthesis.
Which enzyme converts glycerol to glycerol-1P?
Glycerol kinase
What 3 ketone bodies are produced in the body?
- Acetone
- Acetoacetate
- beta-hydroxybutyrate
Where are ketone bodies produced?
Acetone and b-hydroxybutyrate in mitochondia in the liver.
Acetoacetate is formed from decarboxylation of acetone.