Lipids 2 Flashcards
Where does beta oxidation of fatty acids occur
Matrix of the mitochondria
State briefly what the beta oxidation pathway involves.
Fatty acids degrade two carbons at a time to form Acetyl CoA, NADH and FADH2
Explain fully the 3 stages of beta oxidation
Activation - The fatty acids are activated to form fatty acyl CoA in the cytosol
Transport - The carnitine shuttle transfers long chain fatty acyl CoA from the cytoplasm to the matrix of the mitochondria
Degradation - Fatty acyl CoA is dehydrogenated to form to form FADH2 and other intermediates.
This intermediate is then hydrated (requires H2O).
This intermediate is then dehydrogenated again to form NADH.
Thiolysis then occurs to form Acetyl CoA
Cann fatty acids be converted into glucose?
No because no fatty acid is gluconeogenic
What does thiolysis produce?
Acetyl CoA
which feeds into the citric acid cycle
What happens to excess acetyl CoA?
They form ketone bodies (because acetyl CoA is NOT gluconeogenic)
State the role of peroxisomes.
Beta oxidation of long chain fatty acids (>=22 carbons)
Describe what happens during fasting/starvation.
Glucose supplies run low so excess acetyl CoA from fat metabolism can be made into ketone bodies
State where ketogenesis occurs.
Liver
State what is produced during ketogenesis.
Acetone
Acetone is expelled during expiration because acetone is
Too volatile and unstable to be used as a metabolite
State the main ketone bodies.
Acetoacetate and 3-hydroxybutarate
Each beta oxidation cycle forms
1 Acetyl CoA
1 NADH
1 FADH2
