Review II- 10/16/21 Flashcards
Lipids
Hydrophobic molecules extracted from cells by non-polar solvents which associate with each other, excluding water
Fatty acid based lipids
Ampipathic, micelle forming, includes TAGS
Isoprenoids
Cholesterol
- Membranes
- Signals
- Cofactors
- Fat soluble vitamins
Linoleic acid
Omega 6 fatty acid, 18:2 delta 9,12
Linolenic acid
Omega 3 fatty acid, 18:3 delta 9,12,15
Essential fatty acids
omega 6 and omega 3
Long chain fatty acid absorption
Absorbed in SI, incorporated into chylomicron then transported by lacteals to subclavian vein
Medium chain FA absorption
More easily hydrolyzed, absorbed and enter mitochondria directly, enter portal circulation like carbs
Treatment for premature infants, epilepsy, chronic pancreatitis
Short chain Fatty acids
Produced by colon microbiome, 6-10% of energy, 80% of colonocyte energy, can cross blood brain barrier
Fatty acid melting temp effect
Cis double bonds biggest effect in lowering, longer length higher MP, trans lowers a little
Critical micelle concentration
Concentration of free FAs in H20 that they start forming micelles
Digestive enzymes
Lingual lipase, gastric lipase, pancreatic lipase (stimulated by CCK)
CCK
Stimulates pancreatic lipase and PLA
Cholate
AKA cholic acid, is a bile salt, 95% recycled
Absorption of long chain FAs
Either passive diffusion across membrane or mediated by Fatty acid transferases
NPC1L1
Helps cholesterol uptake into cells
Exetimibe
Blocks the action of NPC1L1
ACAT
Esterifies cholesterol to acetyl CoA
Problems leading to malabsorption and steatorrhea
-Biliary obstruction
-Pancreatic diseas
-celiac disease
Loss of essential FAs and fat soluble vitamins
TAG synthase
Reassembles TAGs in intestinal epithelia from 2-MAG and 2 Acyl-CoA
ApoB48
On chylomicrons, recognized by LRP for uptake in liver
MTP
Microsomal transport protein, loads lipids onto ApoB48 particle
Abetalipoprotemia aka Bassein-Kornzweig disease
Lack of MTP, very low serum levels of TAG and CE
Apo C-II
Cofactor for LPL
Serum MAG hydrolase
Take 2 MAG and turns to glycerol and FA
Apo E
Stimulates hepatic triglycerol lipase on liver (HTGL)
Hypercholesterolemia
High LDL
Foam cells
Macrophages that have eaten oxidized LDL in the tunica intima, secrete MMP and growth factors to stimulate smooth muscle growth
Apo-B100
On VLDL and LDL, recognized by LDL receptor
Lysosomal acid lipase
Has cholesterol esterase activity that creates FC
PCSK9
Promotes degradation of LDL receptor, inhibition lowers plasma LDL levels
LDL receptor half life
About 20 hours, one trip every 10 mins
LDL half life
Around 3 minutes
How to get rid of cholesterol
Excreted through skin and digestive tract, make steroids
Regulation of HMG coA reductase
FC leads to down in gene transcription and amount of enzyme
Lack of FC leads to increase in transcription
Statins
Phosphorylation by AMPK
Products of isoprenoid pathway
Cholesterol, ubiquinone, Dolichol, farenesylated proteins
LCAT
Esterizes FC to FA CE in HDL, removes extra cholesterol, activated by ApoA1
SRB1
Scavenger receptor, picks up HDL for degradation
CETP
Cholesterol ester transport protein, transfers CEs to VLDL and TGs to HDL
