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28 Cards in this Set
- Front
- Back
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what is lipogenesis
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the biosynthesis of fatty acids
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what is the main organ of lipogenesis
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the liver
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where does lipogenesis occur
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in the cytosol
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what role does lipogenesis play in humans
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lipogenesis is not critical in humans but does play a role in obesity and is inhibited by type 1 diabetes
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what Carbon can humans not desaturate past
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C-10
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what are the two fatty acids we must derive from plant oils
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linolenic and linoleic
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what are the two major steps in lipogenesis
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acetyl CoA > Malonyl CoA
formation of palmatate |
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what is the commited step in lipogenesis
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acetyl CoA > malonyl CoA
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what is essential for Acetyl CoA carboxylase to function
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biotin (coenzyme)
citrate/isocitrate |
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what can stimulate the formation of acetyl CoA carboxylase
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dephosphorilation
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what stimulates dephosphorilation
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insulin
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what can deactivate the function of acetyl CoA carboxylase
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phosphorilation
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what stimulates phosphorilation
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glucagon
epinepherin |
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what can inhibit acetyl CoA carboxylase becoming active
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palmitoyl CoA
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what is uniques about the 2nd step of lipogenesis
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7 distinct enzyme activities
6 cycles total final product palmitate has 16 carbons |
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what occurs in the 2nd step of lipogenesis
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malonyl loses its CoA and binds to a cysteine group. on the other SH site is a acetyl group. The acetyl group will condense to the malonyl group forming an acyl group. at the end of the first cycle the acyl group will move to the free SH site and a new malonyl will bind to the free SH site.
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what adds the carbons in the 2nd step of lipogenesis
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malonyl
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what occurs if
high fat intake/low carb intake |
inhibition of synthesis of acetyl CoA carboxylase
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what occurs if
starvation/fasting |
inhibition of synthesis of acetyl CoA carboxylase
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what occurs if
high carb/low fat intake |
activation of synthesis of acetyl CoA carboxylase
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where does denaturation and elongation occur
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in the endoplasmic reticulum
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what are the essential fatty acids derived from linoleate
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ecosonoids and prostaglaudin
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what is needed for the liver and adipose tissue to produce glycerol 3-p
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liver : glycerol
fat cells/adipose tissue: glucose |
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what must fat cells/adipose tissues undergo in order to store fatty acids
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glycolysis must occur in order for fatty acids to be stored in adipose tissue and fat cells
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what does the liver use to produce glycerol 3-p
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glycerol is hydrolized by glycerol kinase
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how are TAGs transported?
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the VLDL is released from the liver into the blood stream >
the VLDL then gets hydrolized by the LPL and the fatty acids diffuse into the fat cell where they are then turned back into TAGs > VLDL remnants reenter the liver |
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how are VLDL made in the liver
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TAGs are synthesized in the liver and then combined with cholesterol, apoproteins, and phospholipids to make a VLDL
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why can't TAGs just float in the blood stream
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because they are not capable of diffusing into the fat cells or other forms of tissue
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