Lipoprotein structure and function

Question 1

3 types of lipid complexes and their cores

Answer 1

1. vesicle - aqueous core
2. micelle - no core
3. microemulsion - hydrophobic core

Question 2

what is structure of lipoprotein

Answer 2

1. phospholipid shell with apolipoproteins embedded

2. filled with triglycerides and cholesterol esters

Question 3

order of lipoproteins from least to most dense

Answer 3

CM<HDL

Question 4

apolipoproteins in HDL

Answer 4

A,C,E

Question 5

apolipoproteins in LDL

Answer 5

B100

Question 6

order of lipoproteins from least to most protein

Answer 6

CM<HDL

Question 7

order of lipoproteins from most to least triglcerides

Answer 7

CM<HDL

Question 8

3 non-exchangable lipoproteins

Answer 8

Apo(a), B100, B48

Question 9

feat of apoA-1

Answer 9

main HDL - activates LCAT

Question 10

feat of apoB

Answer 10

key structural protein of all but HDL

Question 11

what is exogenous lipoprotein metabolism path

Answer 11

1. lipids from diet
2. abs. by small intestine
3. come out as CM
4. CM to capils.
5. LPL breaks down to give FFAs
6. left with CM remnant which goes to liver to bing with LDL-R

Question 12

endogenour path

Answer 12

1. liver produces VLDL
2. VLDL to capils
3. LPL makes FFAs
4. IDL left over and goes to liver or become LDL
5. LDL then meets LDL receptor for pick-up

Question 13

what is LDL-receptor

Answer 13

present in liver adrenal some tissues, not heart, skeletal muscle - binds apo-B

Question 14

what is LDL receptor-like protein

Answer 14

like LDL-r but recognizes others besides just apo-B

Question 15

what is LPL

Answer 15

hydrolyzes TG of CMs and VLDL

Question 16

what is heptic lipase

Answer 16

functions as both lipase and phospholipase with IDL and HDL

Question 17

how does cholesterol come into small intestine

Answer 17

chol. transporter

Question 18

how is chol. excreted back into lumen

Answer 18

ABCA or ABCG transporter

Question 19

how much chol. is synthesized vs. consumed

Answer 19

syn. 900 mg/day
consume 300 mg/day
1200 fecally excreted

Question 20

what happens of problem in LDL-r

Answer 20

doesn’t get taken up and get hypercholesterolemia - FH

Question 21

3 causes of hypercholesterl

Answer 21

1. mutation of LDL-r
2. mutation of apo-B ligand - can’t grab LDL-r
3. mutation in PCSK9 - limits bind and endocytosis

Question 22

2 common disorders of LDL or VLDL metabolism

Answer 22

1. poor clearance due to LDL rec

2. VLDL overproduction in diabetes of metabolic syndrome

Question 23

how is HDL raised

Answer 23

can’t pharma - excercise

Question 24

how much do men and women benefit from HDL

Answer 24

women - 3%

men - 2%

Question 25

where does apo-A1 come from

Answer 25

liver 70%

intest. 30%

Question 26

how does HDL protect atherosclerosis

Answer 26

reverse chol. transport- takes it out of cells in peripheral tissue and bring back to liver

Question 27

what turns HDL to VLDL and LDL

Answer 27

CETP - choleteryl ester transfer protein - have tried unsuccessfully to block in past