01 TAG & Phospholipid Flashcards
Where does TAG synthesis happen mostly?
Liver and adipose tissue
What are the substrates dor TAG ?
Glycerol and 3 FA(fatty acid)
What is the precursor for TAG and Glycerophospholipids ?
Phosphatidic acid
What is the common intermidiate compound for the synthesis of triacylglycerol?
Glycerol 3-p Which deffer in liver and adipose tissue
Where is glycerol 3-p produced?
In liver, by phosphorilation of glycerol by using enzyme glycerol kinase.
Or by reduction of dihydroxyacetone phosphate(DHAP) which is derived from glycolysi.
In adipose tissue only by reduction of DHAP
Where is glycerol kinase enzyme present?
In the liver. And it is absent in adipose tissue, that is why adipose tissue produces glycerol 3-p by only DHAP and not by phosphorylation of glycerol.
What is the way glycerol 3-p is produced in adipose tissue?
Only by DHAP which is an intermediate of Glycolysis.
So glycerol 3-p is produced by reduction of DHAP.
An important connection between carbs and lipid metabolism?
DHAP (dihydroxyacetone phosphate)
What happens when you eat alot of carbs?
Carbs are converted into adipose tissue ( Triglycerols)
What is the common intermediate for triglycerol synthesis in both liver and adipose tissue?
Glycerol 3-phosphate
Glucose which comes from carbs metabolism is converted into DHAP then into Glycerol 3-p. Where does this happen?
Liver and adipose tissue
Glycerol is converted to glycerol 3-p. Where this happens?
In liver only.
TAG produced from ……………… is packaged with cholesterol, phospholipids and protiens to form …………… .
Liver
VLDL
Triglecerol (TAG) formed in liver goes to …………
Blood as VLDL
Triacylglycerol (TAG) formed in adipose tissue is ……..
Stored in adipose
How many fatty acids (FA) are needed to convert glycerol 3-p to TAG ?
3 FA
2 of them used in ( glycerol 3-p to phsphatidic acid )
1 is used ( diacylglycerol to triacylglycerol )
In TAG SYNTHESIS , glycerol 3-p is converted to ?
Glycerol 3-p to phosphatidoc acid to diacylglycerol to triacylglycerol(TAG)
In which step of TAG synthesis phospfate is removed?
In converting phosphatidic acid into diacylglycerol
Adipose tissue stores fatty acids(FA) only when ………..
Glycolysis is activated which means in fed state which means when insulin is increased in blood
When doe the adipose tissue storage of TAG increases?
After a meal whan insulin levels are elevated in blood
In ………. State, in adipose tissue, glucose is converted into glycerol 3-p
Fed state
During fasting state a decrease in insulin and an increase in glucagon cause ………
cAMP levles rise in adipose tissue.
The rising of cAMP stimulates lipolysis.
…………. Stimulates lipolysis by acting as a 2nd massenger.
Glucagon
What enzyme acts in fasting state that comverts TAG into glycerol and FA ?
Hormone Sensitive Lipase (HSL)
What enzyme works to degrade trigleceride ?
(HSL) hormone sensitive lipase enzyme
What is Triacylglycerol (TAG) hydrolysis?
When TAG is degraded to glycerol and FA.
by using the enzyme HSL
HSL removes ester bonds between glycerol and FA
Lipase degrades TAG into …………. Which is degraded again by using lipase into ……… which again degraded into ………. By using lipase that breaks the ester bonds between glycerol and FA.
Diacylglycerol
2-monoacylglycerol
Glycerol
Free FA which is removed while degradation by using enzyme lipase (HSL) are used for what?
These free FA breaks down into acetyle co-A , then it inters the citric cycle where these are oxidized.
So oxidation happens to free FA
What happens to free glycerol that is produced from degradation of TAG ?
Goes to glucogenesis for energy
Compound lipods are devided into
- Phospholipids which are devided into 2 types ( glycerophospholipids and sphingophospholipids )
- Glycolipids
Glycolipids examples
Cerebrosides ( for brain)
Gangliosides ( for ganglions)
Examples of glycerophospholipods
Lecithins ( surfactant)
Cephalins ( blood clotting)
Inositol ( hormone action)
What is lecithins and what is it used for?
It is a type of glycerophospholipids , and it is used as a surfactant
What is is cephalins and what is it used for?
It is a glycerophospholipid and is used for blood clotting
What is is inositol and what is it used for?
It is a glycerophospholipid and is used as a hormone
What is is sphingomyelin and what is it used for?
It is a sphingophospholipid and it is used in the nervous system , myelin sheets, brain and also in lungs
What does a simple lipid contain?
Glycerol + 3 FA
What does a phospholipid contain ?
Glycerol+ 2FA + phosphate + nitrogen base
What does a sphingolipid contain?
Sphingosine + FA + p + nitrogen base
Where are glycerophospholipids synthesized?
Smooth endoplsmic reticulum
Perecursors of glycerophospholipids ?
Phosphatidic acid and 1,2 diacylglyceeol (DAG)
Is glycerophospholipids an intermidiate in TAG metabolism?
Yes
Is phosphatidic acid an intermidiate for TAG ?
Yes
