Exam 3: Triacylglycerol Breakdown and Ketone Bodies Flashcards
What proportion of our energy needs come from digested triacylglycerols?
1/3.
Why are fats relatively more energy-filled molecules?
Because they exist in a reduced state, allowing them to undergo different reactions.
Fatty acids also carry less water, and so they can be packed more tightly.
What is the role of glycerol kinase?
To phosphorylate glycerol using ATP.
What is the role of glycerol-3P dehydrogenase?
It oxidizes glycerol-3P to dihydroxyacetone phosphate (DHAP) with the reduction of NAD+.
Where are fats degraded into fatty acids and glycerol?
In the cytoplasm of adipocytes.
Where does B-oxidation of fatty acids in animals occur?
Within the mitochondria.
What size must the fatty acids be to diffuse freely through the membrane?
Less than 12 carbons.
Through what are larger fatty acids transported into the mitochondria?
Larger fatty acids must pass through acyl-carnitine transporters.
What must occur for a fatty acid to be transported?
CoA must be attached via a thioester bond.
What must occur first, before the thioester bond is formed on the fatty acid?
The fatty acid must be activated by fatty acyl-CoA synthetase.
List the 4 steps of B-carbon oxidation.
- Dehydrogenation of alkane to alkene.
- Hydration of alkene.
- Dehydrogenation of alcohol.
- Release of acetyl-CoA.
Why is enol-CoA hydratase unable to process unsaturated fatty acids?
Enol-CoA hydratase only binds at trans double bonds.
What are the roles of the isomerase and reductase enzymes in unsaturated fatty acid reactions?
The isomerase converts a cis bond to a trans bond.
Reductase reduces cis bonds not at c3.
