LECTURE 23 - METABOLISM OF FATTY ACIDS Flashcards
Identify the commitment step for fatty acid synthesis
Conversion of acetyl-CoA to malonyl-CoA
Explain the need for the transfer of Acetyl CoA for fatty acid synthesis
all of the carbon atoms of a fatty acid are derived from acetyl-CoA (C2), it provides the necessary building blocks for the elongation of the fatty acid carbon chain
Describe the role(s) of malonyl CoA in fatty acid synthesis
Malonyl-CoA:
Is used as a substrate for fatty acid synthesis
Inhibits fatty acid oxidation
What enzyme breaks down triacylglycerol? What are the products?
Lipases hydrolyze triacylglycerol to glycerol and three fatty acid molecules
Describe the use of glycerol in triacylglycerol in humans
Glycerol from triacylglycerols is converted to an intermediate for glycolysis or gluconeogenesis
Describe the use of fatty acids in triacylglycerol in humans
Fatty acids from triacylglycerols are used for energy production through fatty acid oxidation
Explain how fatty acids are transported into mitochondria
- Acyl-CoA to Acylcarnitine, which crosses into the mitochondria
- Acylcarnitine is then converted back to acyl-CoA once in the mitochondria
Identify the rate-limiting step of fatty acid oxidation
The conversion from acyl-CoA to Acylcarnitine
Determine the end products of β-oxidation when a fatty acid is given
– C16 fatty acid → 8 acetyl-CoA
(even Fatty Acid)
– C17 fatty acid → 7 acetyl-CoA + 1 propionyl-CoA
** Fatty acids with an odd number of carbons produce a propionyl-CoA (C3) at the end of the cycle
Explain how fatty acid synthesis and fatty acid oxidation are regulated.
- HIGH levels of malonyl-CoA
– Fatty acid synthesis is active
– Carnitine palmitoyltransferase I (CPT1) is inhibited, which keeps Fatty Acids from entering the mitochondria for oxidation - LOW levels of malonyl-CoA
– Fatty acid oxidation is active - Malonyl-CoA is produced by acetyl-CoA carboxylase (ACC)
What is the key regulator of fatty acid synthesis and fatty acid oxidation?
malonyl-CoA
