Cholesterol Metabolism And Lipoproteins

Front 1

A lipoprotein made chiefly out of dietary lipids

Back 1

Exogenous lipids

Front 2

A lipoprotein that originates in the liver

Back 2

Endogenous lipids

Front 3

Chylomicron source and endogenous/exogenous?

Back 3

Source: Intestines (from dietary fat)
Exogenous

Front 4

Chylomicrons are made primary of?

Back 4

Triglycerides

Front 5

VLDL source and endogenous/exogenous?

Back 5

Source: Liver
Endogenous

Front 6

VLDL is made primarily of?

Back 6

Triglycerides

Front 7

IDL source?

Back 7

VLDL

Front 8

IDL is made primarily of?

Back 8

Triglycerides & Cholesterol esters

Front 9

IDL is intermediate between ___ and __

Back 9

VLDL and LDL

Front 10

LDL sources?

Back 10

VLDL
Liver

Front 11

LDL is primarily made of?

Back 11

Cholesterol Esters
(Cholesterol-carrying lipoprotein

Front 12

HDL2 sources?

Back 12

Intestines
Liver

Front 13

HDL2 is primarily made of?

Back 13

Protein
Cholesterol Esters

Front 14

HDL3 sources?

Back 14

Intestine
Liver

Front 15

HDL3 is primarily made of?

Back 15

Protein
Cholesterol Esters

Front 16

HDL2 & 3 mainly does what to cholesterol?

Back 16

Takes away from cell --> dumps from body

Front 17

LDL can lead to what conditions?

Back 17

Hypercholesterolemia
CHD

Front 18

Proteins that bind to lipids to form lipoproteins, which transport the lipids through the lymphatic and circulatory systems.

Back 18

Apoprotein

Front 19

Apo A1 associates with which lipoproteins?

Back 19

Chylomicrons
HDL

Front 20

Major function of Apo A1?

Back 20

Major protein of HDL
Activates LCAT

Front 21

Apo A2 primarily associates with which lipoproteins?

Back 21

Chylomicrons
HDL

Front 22

Functions of Apo A2?

Back 22

Primarily in HDL
Enhances hepatic lipase activity

Front 23

Apo A4 primarily associates with which lipoproteins?

Back 23

Chylomyicrons
HDL

Front 24

Functions of Apo A4?

Back 24

Unknown
(May transport proteins between HDL & chylomicrons)

Front 25

Apo B48 primarily associates with which lipoproteins?

Back 25

Chylomicrons

Front 26

Functions of Apo B48?

Back 26

Found exclusively in chylomicrons
Lacks LDL receptor-binding domain
Derived from B100 gene via RNA editing in intestinal epithelium (losing LDL receptor domain)

Front 27

Apo B100 primarily associates with which lipoproteins?

Back 27

VLDL, IDL, LDL

Front 28

Functions of Apo B100?

Back 28

Only protein of LDL
Binds LDL receptor (receptor ligand)
largest human proteins

Front 29

Apo C1 primarily associates with which lipoproteins?

Back 29

Chylomicrons, VLDL, IDL, HDL

Front 30

Functions of Apo C1?

Back 30

Unknown

Front 31

Apo C2 primarily associates with which lipoproteins?

Back 31

Chylomicrons, VLDL, IDL, HDL

Front 32

Functions of Apo C2?

Back 32

Activates lipoprotein lipase --> removes fat from fat carrying lipoprotein --> Deliver to adipose/muscle for energy

Front 33

Apo C3 primarily associates with which lipoproteins?

Back 33

Chylomicrons, VLDL, IDL, HDL

Front 34

Functions of Apo C3?

Back 34

Inhibitor of Lipoprotein Lipase

Front 35

Cholesterol ester Transfer Protein (CETP) associates primarily with which lipoproteins?

Back 35

HDL

Front 36

Apo D is primarily associates with which lipoproteins?

Back 36

HDL

Front 37

Functions of Apo D?

Back 37

Closely associated with LCAT

Front 38

Functions of CETP?

Back 38

Exclusively associated with HDL
Cholesterol Ester Transfer

Front 39

Apo E is primarily associated with which lipoproteins?

Back 39

Chylomicron remnants, VLDL, IDL, HDL

Front 40

Functions of Apo E?

Back 40

Binds to B/E receptors in hepatocytes

Front 41

Which Apo E allele is most common?

Back 41

Apo E3

Front 42

T/F: You need just one normal Apo E allele for normal clearance

Back 42

True

Front 43

Which Apo E allele is the non functional ligand?

Back 43

Apo E2

Front 44

Apo E4 is associated with what disease?

Back 44

Alzheimer's Disease

Front 45

Which apoproteins activate and which inhibit lipoprotein lipase?

Back 45

Activates: Apo C2
Inhibits: Apo C3

Front 46

Apo H is primarily associated with which lipoproteins?

Back 46

Chylomicrons

Front 47

Functions of Apo H?

Back 47

Triglycererol metabolism

Front 48

Apo A lipoprotein is primarily associated with which lipoproteins?

Back 48

LDL

Front 49

Function of Apo A lipoprotein?

Back 49

Disulfide bonds to Apo B100
Forms LDL complex
Resembles plasminogen
Slows breakdown of blood clots

Front 50

T/F: Apo A lipoprotein is very atherogenic

Back 50

True

Front 51

Chylomicron Metabolism Pathway

Back 51

Epithelial cells in intestine secrete Nascent Chylomicron containing Apo B48 --> Transported into lymph/blood --> HDL (syn. In liver) has Apo C2 & E proteins --> Gives to Chylomicron --> Activates lipoprotein lipase (on lumen of small blood vessels) --> Used for energy --> Chylomicron remnants (lack fatty acids) --> Taken up by B/E Receptors on Liver (via Receptor-mediated endocytosis) --> Syn Bile Acids --> Solubalize Cholesterol

Front 52

VLDL--> IDL --> LDL Cascade Pathway

Back 52

VLDL syn. In Liver --> secreted in blood --> lipoprotein lipase removes fatty acids (transports to adipocytes storage for fuel --> VLDL delipidated --> Transfers triglycerides to HDL/gives cholesterol --> IDL (lost C Protein; Has Apo E & Apo B100) (retaken up by liver) --> Delipidated --> LDL (cholesterol-rich) --> Takes cholesterol to cells for synthesis & membrane.

Front 53

Most of LDL is synthesized where?

Back 53

Liver

Front 54

Reverse Cholesterol Transport Pathway

Back 54

Free Cholesterol diffuse out of cell --> Nascent HDL particle (syn in liver & intestines)--> Esterified w/ fatty acids (via LCAT) --> Transferred to VLDL via Cholesterol Transfer Protein (CETP) --> Uptake by B/E Receptor in Liver --> HDL taken up by scavenger receptors in Liver (has no receptors on any cell in body)

Front 55

T/F: LDL receptors are on almost every cell

Back 55

True

Front 56

Why does a cell need LDL receptors?

Back 56

Traps LDL in plasma to bring into the cell so the cell doesn't have to synthesize all the needed cholesterol

Front 57

The binding site of the LDL receptor contains?

Back 57

Negatively charged proteins

Front 58

The binding site of the LDL Receptor binds to what?

Back 58

The positive charge of Apo B-100 on LDL

Front 59

What increases the synthesis of LDL receptors?

Back 59

SREBP

Front 60

What inhibits LDL receptor synthesis?

Back 60

Statins (simvastin, lovastatin, movastatin)
Glucagon
Cortisol

Front 61

Increased intracellular cholesterol increase/decreases LDL receptor synthesis?

Back 61

Decreases

Front 62

How are foam cells formed?

Back 62

LDL floats in plasma too long and gets oxidized by free radicals. Crosses endothelium into artery wall --> Macrophages engulf LDL via Scavenger Receptor --> fill with cholesterol --> Becomes Foam Cell and releases cytokines/GF. Leads to atherosclerosis

Front 63

Type 1 Hyperlipoproteinemia Defects and Symoptoms?

Back 63

Deficient/abnormal LPL
Deficient Apo C2 (normally activates lipase)
-->
Increase chylomicrons, low LDL/HDL, epigastic pain, turbid retinal vessels

Front 64

Type 2a Hyperlipoproteinemia Defects and Symoptoms?

Back 64

Defect in 4 classes of LDL Receptor
-->
Reduced LDL clearance --> High LDL --> CAD/Plaques

Front 65

Type 2b Hyperlipoproteinemia Defects and Symoptoms?

Back 65

Increased LDL, Delayed VLDL clearance
-->
Increased CAD

Front 66

Type 3 Hyperlipoproteinemia Defects and Symoptoms?

Back 66

Apo E2 homozygous
-->
Xanthomas; High cholesterol --> CAD/plaques

Front 67

Type 4 Hyperlipoproteinemia Defects and Symoptoms?

Back 67

Elevated VLDL production associated with glucose/hyperinsulinemia

Front 68

Type 5 Hyperlipoproteinemia Defects and Symoptoms?

Back 68

Elevated VLDL/Chylomicrons (unknown cause)
-->
Hypertriglyceride, Hypercholesterol, Decrease LDL/HLD

Front 69

Familial Hyperalphalipoproteinemia Defect and Symptoms?

Back 69

Increased HDL
-->
Beneficial for health!

Front 70

Familial Ligand Defective apo B Defect and Symptoms?

Back 70

Gly--> Arg & Cys --> Arg mutations
-->
increase LDL, normal VLDL/HDL
Hypercholestolemia/CAD

Front 71

Familial LCAT Deficiency Defect and Symptoms?

Back 71

LCAT absence. HDL unable to take up cholesterol
-->
Decreased plasma cholesterol esters
Abnormal LDL/VLDL

Front 72

Heparin releasable hepatic lipase deficiency Deficiency and Symptoms?

Back 72

Accumulation of Tg rich HDL & LDL
-->
Xanthomas/ CAD

Front 73

Abetalipoproteinemia Deficiency and Symptoms?

Back 73

Defective Apo B expression --> No chylomicrons/VLDL/LDL
-->
Malabsorption of fat; ataxia neuropathy

Front 74

Familial Hypobetalipoproteinemia Deficiency and Symptoms?

Back 74

20 apo B gene mutations, low VLDL, low LDL
-->
Mild/no pathological changes

Front 75

Tangier Disease Deficiency and Symptoms?

Back 75

Reduced HDL. Normal chylomircons/VLDL
-->
Elevation in VLDL