Lipid anabolism Flashcards
What is lipogenesis?
Fatty acid synthesis
Where can lipogenesis occur?
Liver, kidney, mammary glands, adipose tissue
Where is the main organ for lipogenesis?
The liver - occurs when we take in too much energy
What happens if we take in too much energy?
Conversion to fatty acids and triglycerides in the liver
The free fatty acids are transported in the plasma bound to albumin
Triglycerides formed in the liver are transported to adipose tissue by VLDL for storage
is lipogenesis reductive or oxidative?
Reductive process, so it needs electrons
what is the precursor molecule for lipogenesis?
Acetyl - CoA
Where does synthesis of fatty acids from adetyl CoA occur?
In the cytoplasm of the liver
Where is acetyl-CoA generated?
In the mitochondria
How is acetyl groups moved into the cytoplasm from the matrix?
Via citrate - product of the TCA cycle
What is the first step in the synthesis of fatty acids from acetyl CoA?
The activation of acetyl Co A to malonyl-CoA by acetyl CoA carboxylase
what does fatty acid synthase do?
Makes only saturated straight chain fatty acids from malonyl-CoA, acetyl-CoA and NADPH
What does fatty acid synthase contain?
An acyl-carrier protein (ACP)
what is the electron doner for lipogenesis?
NADPH
When is the fatty acid released by fatty acid synthase?
16C is the longest it can make
what is the control of fatty acid metabolism?
Synthesis of fatty acids can only occur when there is lots of carbs and every available - or cells wouldnt expend ATP to make fatty acids
What is the essential substance in regulating fatty acid synthesis and degradation?
Acetyl-CoA carboxylase
what hormones regulate Acetyl-CoA carboxylase?
Insulin - only released when there is lots of energy, it is the hormone of the fed state. (lots of acetly coA around)
Glucagon - lack of carb in the bloodstream - switches it off no synthesis of fatty acids
adrenaline - need energy, so no synthesis of fatty acids
Citrate - citrate levels are high when there are lots of acetly-CoA present and ATP are abundant
When can the synthesis of triglycerides take place?
Requires glycerol-3-phosphate
Liver produces G-3-P from glycerol
what does triglyceride formation involve?
Involves esterification
