Lipids 2 Flashcards
What does the body use to breakdown fatty acids to produce energy?
Beta oxidation
Where does beta oxidation occur?
Mitochondrial Matrix
What does B oxidation produce (stored chemical energy)?
Acetyl CoA, FADH2, NADH
What are the three stages of B ox?
- Activation
- Transport
- Degredation
Where are the FA’s activated?
Cytosol
Where are FA’s transported to?
Mitochondria
What happens to the fatty acid during activation?
Has a CoA group attached to it to produce Acyl CoA
What replaces the CoA of Acyl CoA to allow it to move into the mitochondrial matrix?
Carnitine
Can Acyl CoA move into the outer membrane of the mitochondria?
Yes - when inside it it converted by carnitine palmitoyl transferase 1 to form acyl carnitine.
How does acyl carnitine enter the mitochondrial matrix?
Through transferase
What happens when it arrives?
It is converted to Acyl CoA through carnitine palmitoyl transferase 2.
What happens to the carnitine produced by the action of carnitine palmitoyl transferase 2?
It moves back into the outer membrane through transferase.
What is carnitine palmitoyl inhibited by to stop synthesis and degradation at the same time?
Malonyl CoA
What happens when their is a deficiency of CAT-1?
No B ox occurs.
- Hypoglycaemia
- Treated with IV glucose or consuming short chain FA’s.
Do short/medium chain FA’s need transport with the carnitine shuttle?
No
What are the 4 main steps of degradation? And what does each stage produce?
- Dehydrogenation (produces FADH2)
- Hydration
- Dehydrogenation (NADH)
- Thiolysis (acetyl CoA)
What does each B ox produce?
One acetyl CoA and a FA species 2 carbons shorter than the original.
How much acetyl CoA, NADH and FADH2 does complete B ox of palmitate produce?
8 acetyl CoA, 7 NADH, 7 FADH2
What is the ATP yield per FADH2?
2
ATP yield per NADH?
3
ATP yield per acetyl CoA
12
What happens to FA’s longer than 22 C’s before B ox can occur?
Preliminary B ox in the peroxisomes occurs, the shorter chain is then attached to carnitine and diffuses into the mitochondria.
Why can FA’s not be used to produce glucose?
Acetyl CoA back to pyruvate is very unflavoured thermodynamically.
What is acetyl CoA converted to when there is an excess of it?
Ketone bodies
