lipids, cholesterol biochemistry Flashcards
function of chylomicrons
delivery dietary lipids
function of VLDL
deliver endogenous lipids
function of IDL
return endogenous lipids to the liver and are a LDL precursor
function of LDL
delivery cholesterol to cells
function of HDL
reverse cholesterol transport
what are the least dense lipoprotein molecules
chylomicrons
what are the most density
HDL
what are the three apolipoproteins on chyloicrons
apoC II
apoB-48
ApoE
apoA-1
where are chylomicrons made
in the intestine
mature chylomicrons have what two apoplipoproteins taht they acquired in the blood
apoE and ApoCII
what is the function of apoCII
helps activate lipoprotein lipase
what is the function of ApoE
when exposed it acts as a ligand for receptor that allows lipoprotein clearance
who helps give the liporpoteins to chylomicrons in the blood
HDL (donates ApoCII and ApoE)
what are the receptors for chylomicron remnants going into the liver
LRP for ApoE
VLDL transports ________lipids and the apoprotein for VLDL is __________ and has rich TG content
endogenous, apoprotein B 100
______activates LPL
apoCII
beta remnants of VLDL are called
IDL
IDL remnants can acquire additional cholesterol from HDL particles in the circulation and become
LDL particles
what is the apoprotein on LDL cells
apob 100
______returns cholesterol to the liver
HDL
what are the two important apoproteins on HDL
apoA-1 and ApoE
_____is activated by ApoA-1
LCAT
what does LCAT do
esterifies cholesterol
function of ApoA1
actiaves LCAT, structural HDL component
function of apoB48
assembl/secretion of chylomicrons from the small intestine
apob100 function
VLDL assembly/secretion (liver), VLDL, IDL, LDL structural protein LDL receptor ligand
function of apo(a)
linked via a disulfide bond to apoB100
how do you calculate LDL from a cholesterol screen
LDL equal to total cholesteroal–HDL-1/5 triglycerides (if less than 400)
what is the rate limiting step of cholesterol synthesis
HMG CoA reductase
_______- and __________-activate HMG-COA reductase
insulin and thyroxine
Glucagon and sterols _____to HMG Coa Redutase
deactivate it
what is the most reliable marker for unstable atherosclerotic plaque
CRP
homocysteine competes with __________binding on methylases leading to decreased methylation
SAM
deficiency in what vitamines has a correlation with atherosclerosis
B vitamins
type I hyperlipidemias primary cause
apocII or LPL deficiency
type I lipoproteinf ractions
increased chylomicrons, increased TG
type IIa liporptein fractions
LDL increased
primary defect for type IIa
defect in the LDL receptor
type IIB lipoprotein fractions
LDL, VLDL, TG
primary defect for type IIb
defect in LDL receptor for endocytosis
type III primary defect
defect in apoE
type IV primary defect
multiple factors
type V defect
LPL deficiency + increased VLDL production
what are the lipoprotein fractions for type III
increased IDL
what are the increased lipoprotein for type IV
VLDL and TG
what are the increaed lipoprotein for type V
VLDL, TG and chyloimicrons
pts with type I also present with
xanthoma, recurrent abdominal pain and hepatosplenomegaly
defects in the LDL-R may be
absent or truncated protein
protein not on the surface
protein doesn’t bind LDL
protein doesn’t cluster or interalize
total cholesterol should be aimed for
less than 200 greater than 20, less that 170 in less than 20
_______reduces absorption of dietary cholesterol
ezetimibe
