lipoproteins

Question 1

lipoproteins consist of

Answer 1

-neutra lipid core-tag and cholestryl esters
- shell of amphipathic apoliporptoetine, phospho, nonesterfifie(free)cholestol

Question 2

size and density

Answer 2

chylomicrons: lowest density, contain most lipid /TAG, least protein

vldl and ldl: denser and higher protein than lipid

hdl: smalles and densest

Question 3

apolipoprotins function

Answer 3

activator or coexnyme for enzymes in metbaolsim

essential compinent of particles

provide recognition sites for cells urfave receptors

Question 4

chylomicron assembled in, funciton

Answer 4

in intestinal mucosa
- carry diestary/Exogenous TAG, choelstrol, fat soluble vitamins and choelstryl esters to peripheral tissues

Question 5

apo b-48 is unique where and where is it assembled

Answer 5

chylomicrons

begins on RER), move thorugh RER and GA

Question 6

Assevmbluu of apo b-48 and lipid into chylo reuires whta

Answer 6

microsomal triglyceride transfer protein (MTP)–>load apo med lipid
- before er to GA

Question 7

what is LPL and what does it do

Answer 7

enxyme tht degrades the TAG contained in chylomicrons–>FAs and glycerol
- ancchored to capillary walls, expecially adipose tissue and cardiac and skeletal

• ## act by apo c-2

Question 8

how is LPL regulated

Answer 8

nutritianal and hormonal level

fed state: increased synthesis in adipose, decreased in muscle

fasting: opposute

Question 9

in chylomoicron remnant formation, what happens to apoliproteins

Answer 9

• apo c is returned to HDL
• apo b and e stays
• remainng particle is removed for circulation by liver. the liver have lipoprotein receptors that recognize apo E. take –>heppatocytes by endocytosis. –>lysosome and hydrolysis happens–>AAs, free cholestrol and FA

Question 10

where are vldl produced and what do they consist of(function)

Answer 10

liver

endogenous TAG, carry this lipid form the liver–>peripheral tissues

Question 11

which apolipoprotein do vldl contain

Answer 11

vldl secreted dirctly into blood by liver as anscent aprticles with apo b-100.

Get apo e and c2 form HDL

Question 12

how do vldl becomes denser

Answer 12

degraded by TAG and appo e and c2 is returned.

-apob-100 retains

• some tag –>hdl. hdl give cholestryl esters . need choelstryl ester transfer protein

Question 13

whta do ldl have high concentration of and what is their function

Answer 13

choelstrol and cholestryl esters

provide cholestrol to the peripheral tossues or return it to the liver

Question 14

how do ldl do their task

Answer 14

bind to plasma membrane lld recprot that recognize apo b-100 (not apo b-48)

Question 15

how does chylomicron remnant, idl and ldl derived cholestrol affect cellular choelstrol content

Answer 15

-high cholestrol inhibit hmg reducate=>de novo cholestorl synthesis decrease

• choelstrol not required: acat esterifies it . transfer FA from a afatyy acyl coa to cholestrol , producing a cholestryl ester that can be stored in cells

Question 16

ldl uptake by macrophage sacvenger receptors

Answer 16

scavenger receptor class a bind to ligands and mediate endocytosis

SR is not downgraded by intracellular cholestrol

cholesteryl esters accumulate in macrophages and cause their transformation into foam cells–>participate in formation of atherosclerotic plaque

Question 17

where are hdl formed an dfunction

Answer 17

in blood by addition of apo A-1(liver and intestine)

serve as resercoir of apo C-2 (transferred to vldl and chylo, act of LPL)

Question 18

what do nascent hdls contain+function

Answer 18

apo a, c and e

take up choelstrol form nonheptic (peripheral ) tissues and return it to liver as cholestryl esterss

Question 19

how is choelstrol esterified in hdl

Answer 19

by plasma enzyme lecithin:cholestrolacyltransferase (LCAT) activated by APO A-1.
- Transfer FA from c2 of PC to choelstrol

Question 20

what is effluc of choelstrol form peripheral cells mediated by

Answer 20

transport ptorin ABCA1

Question 21

what is choelstryl ester uptake by liver mediated by

Answer 21

cell surfcae receptor scavenger receptor class B type 1

Question 22

what is homolog to plasminogen

Answer 22

apo (A), the precursor of blood protease whose target is fibrin. fibrin is main component of blood clots

Question 23

where are steroid hormones synthesized and secretion

Answer 23

adrenal cortex

Question 24

aldosterone

Answer 24

• poduced in outer layer of adrenal cortex
• induced by decrease in plasma Na+/potassium K+ and by hormone angiotensin II