Lipoprotein Lecture (Lecture 2) Flashcards Preview

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Flashcards in Lipoprotein Lecture (Lecture 2) Deck (24):
1

Two ways lipids are suspended in blood

(1) transport of fatty acids in association with albumin
(2) components of lipoproteins

2

Features of lipoproteins

(1) surface composed of a monolayer of amphipathic lipids (phospholipids and unesterified cholesterol) and proteins
(2) anhydrous cose, composed of triacylglycerols and cholesterol esters (anhydrous core - containing no water)

3

What are apolipoproteins?

proteins that bind lipids to form lipoproteins; lipid-binding proteins in the blood responsible for the tranport of triacylglycerides, plasma lipids, cholesterol, estified cholesterol

4

What does "Apo" designate?

"Apo" designates the protein in its lipid-free form

5

Purpose of apolipoprotein

(1) act as recognition sites or ligands for receptors
(2) act as structural components
(3) act as activators or coenzymes for enzymes involved in lipid metabollism

6

How do we make distinctions between each lipoprotein?

tissue of origin and average composition

7

Size and density of lipoprotein particles

(1) chylomicrons - lipoprotein particles lowest in density and largest in size, contain the highest percentage of lipid and the lowest percent of protein
(2) VLDLs and LDLs are successively denser, having higher ratios of protein to lipid
(3) HDLs are the densest

8

How are plasma lipoproteis separated

separated on the basis of their electrophoretic mobility or on the basis of their densities by an ultracentrifugation

9

How are apolipoproteins divided

by structure and function into five ajor classes, A through E, with most classes having subclasses

10

What are the 2 basic phases to lipoprotein metabolism?

(1) processing
(2) clearance

11

Processing of lipoprotein

undergo changes in composition of both surface and core components, during transit in the circulation, converting to the remnant form

12

Clearance of lipoprotein

from the blood, via a receptor-mediated endocytotic process

13

Source and function of chylomicrons?

Intestine. Transport of TAG

14

Major apolipoproteins of chylomicrons?

B48, CII, CIII, E

15

Source and function of VLDL?

Liver. Transport of endogenously synthesized TAG

16

Major apolipoproteins of VLDL?

B100, CII, CIII, E

17

Source and function of LDL?

Formed in circulation by partial breakdown of IDL. Delivers cholesterol to peripheral tissues

18

Major apolipoproteins of LDL?

B100

19

Source and function of HDL?

Liver. Removes "used" cholesterol from tissues and takes it to liver

20

Major apolipoproteins of HDL?

AI and AII, CII, CIII, E

21

Pathways for lipoprotein metabolism?

(1) exogenous pathway
(2) endogenous pathway
(3) reverse cholesterol transport pathway

22

Exogenous pathway

chylomicrons, dealing with dietary lipids

23

Endogenous pathway

VLDL, IDL, LDL, dealing largely with de novo synthesized lipids

24

Reverse cholesterol transport pathway

HDL, dealing largely with cholesterol