Lipids Flashcards
What is a saturated fatty acid?
- maximum # of H bonds
- only single bonds
What is an unsaturated fatty acid?
- “missing” H atoms
- double bonds
- cis or trans configuration
What happens in desaturation of fatty acids?
insertion of a double bond and removal of 2 Hs
What happens in elongation of fatty acids?
2 carbons added at carboxyl end
What is/are the enzyme(s) that are used in the desaturation of linoleic acids
- delta-6 desaturase
- delta-5 desaturase
what are the enzyme(s) used in elongation of linoleic acid?
elongase-5
what are eicosanoids?
- metabolites of 20-carbon fatty acids
- produced by most cells in the body
- hormone-like, but function locally (only on what it’s produced by)
- ie: prostaglandins, thromboxanes, leukotrienes
What is the main dietary and storage lipid?
triglycerides
Where are lipids digested and by what?
- mouth - lingual lipase
- stomach - gastric lipase
- small intestine - pancreatic lipase and cholesterol esterase
What do bile acids do?
emulsify digested lipids
what system do digested lipids go to?
lymph
What is the “good” type of lipoprotein?
high density lipoprotein (HDLs)
what is the “bad” type of lipoprotein?
Low density lipoproteins (LDLs)
more ____ and less ____ makes a higher density lipoprotein
protein; fat
_____ hydrolyzes the triglycerides in chylomicrons into _____ and 2 _____
LPL (lipoprotein lipase); 2-MAG; fatty acids
What are chylomicrons referred to as when they become triglyceride-depleted
chylomicron remnant
how are chylomicron remnants removed from circulation?
through ApoE-mediated interactions with a receptor in the liver
How is LPL activated in chylomicrons
by ApoC
What is reverse cholesterol transport?
when HDL picks up cholesterol around the body and brings it to the liver
what is the main transporter of newly synthesized hepatic TAG?
VLDL
What are the fates of cholesterol in the liver?
- converted into bile acids to replenish the bile acid pool
- secreted “as is” directly with bile, to be eliminated in feces
- Packaged into VLDL and sent around the body
higher HDL levels means more ____ returning to the _____
cholesterol; liver
The complete breakdown of TAG molecule releases 1 _____ and 3 ______
glycerol; fatty acids
What protein is only present in chylomicrons?
ApoB-48
what protein is only present in LDLs and VLDLs?
ApoB-100
What protein is only present in HDLs?
ApoA
