Lipids 2 Flashcards
In the beta oxidation pathway, how many fatty acid carbons does it break down at a time?
2
What are the products of beta oxidation?
Acetyl CoA, NADH, and FADH2 all sources of energy for ATP
Where does beta oxidation occur?
In the mitochondrial matrix
What does FA released from an adipocyte bind to?
Albumen
What are the stages for fatty acid to undergo beta oxidation?
Activation, transport and degradation (explain each)
How is the fatty acid released from adipocytes?
lipolysis
How does the fatty acyl co a cross the mitochondrial walls?
Fatty acyl co a diffuses across the first membrane. The carnitine shuttle is responsible for the movement of the fatty acyl co a across the second membrane- Co a component of the molecule is removed, remaining molecule then binds to carnitine and passes over the membrane with help from translocase. Carnitine is removed and fatty acyl co a is reformed
What is the effect of malonyl co a?
Malonyl is needed for FA synthesis - therefore prevent the synthesis and degradation happening at the same time.
What is the effect of carnitine fatty acyl tranferase or carnitine palmitoyl transferase deficiency?
No beta oxidation
Hypoglycemia
What are the steps of degradation?
Dehydrogenation - produces FADH2
Hydration - Requires H20
Dehydrogenation- To produce NADH
Thyolysis- Cleaved to produce acetyl co a
What is the precursor of FADH2 and NADH
FADH2 = FAD
NADH = NAD+
What happens to acetyl co a produced?
Joins TCA cycle (citric acid cycle)
What carbon products are produced after every beta oxidation cycle?
A carbon species two carbons shorter than the original + acetyl co a
How much ATP does each of the following molecules give / use?
FADH2
NADH
Acetyl Co A
FADH2 = 2 ATP
NADH = 3 ATP
Acetyl Co a = 12 ATP
Where does a preliminary beta oxidation of very long fatty acids take place?
Peroxisomes
Why is the first step (dehydrogenation) less energy efficient?
No FADH2 is produced
What happens to the FA linked to the carnitine?
Diffuses from peroxisome to mitochondria for further oxidation
What happens to acetyl co a levels during fasting / starvation?
Liver flooded with acetyl co a
What is the effect of high acetyl co a levels on pyruvate dehydrogenase?
Pyruvate dehydrogenase is inhibited reducing further acetyl co a formation
What is the effect of high acetyl co a levels on pyruvate carboxylase?
Activates pyruvate carboxylase and therefore increases the oxaloacetate present
What does the amount of ketogenesis depend on?
The amount of acetyl co a, excess is converted into ketone bodies
What muscles use ketone bodies as an energy source?
The skeletal muscles, and the cardiac muscles
What important organ can ketone bodies also provide energy for?
The brain
Where are ketone bodies formed?
The liver, although the liver cannot actually use them!
