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Flashcards in 11.21 D Deck (54):
1

Which lipoprotein doesn't express B48 or B100?

HDL

2

Which lipoprotein expresses B48 in place of B100?

chylomicrons

3

What is the function of apoB-100?

it is the ligand for LDL receptor

4

What is the function of apoB-48?

it is structural

5

What is the function of apoC-II?

it is an activator of lipoprotein lipase

6

What is the function of apoE?

it is a ligand for the LDL receptor

7

Which apoproteins are ligands for the LDL receptor?

apoE and apoB-100

8

apoE is included in what lipoproteins?

chylomicrons and HDL which don't express apoB-100

9

What is the function of apoA-1?

an activator of lecithin:cholesterol acyltransferase (LCAT)

10

What is the function of lecithin: cholesterol acyltransferase (LCAT)?

esterify cholesterol for transport

11

What is the function of lipoprotein lipase?

hydrolyzes triglycerides into fatty acids for uptake into tissue

12

Where is LPL expressed?

in blood vessels

13

What is the function of hepatic triglyceride lipase (HTGL)?

to hydrolyze triglycerides that are arriving at the liver

14

What is the function of cholesteryl ester transfer protein (CETP)?

to transfer cholesterol esters form one lipoprotein to another

15

What is the function of the ABC proteins involved in lipid transport?

they are resposible for the efflux of cholesterol from tissue into HDL

16

What is the function of SR-A?

it is found on macrophages for foam cell formation

17

What is the function of SR-B?

found on hepatocytes for HDL uptake

18

What is acid lipase?

a lipase found in lysosomes that functions at low pH to hydrolyze cholesterol

19

What is the function of LDL-receptor related protein?

uptake of cholesterol-loaded chylomicron remnants and HDL as well as the delivery of cholesterol to the liver for excretion

20

Dietary triglycerides get packaged into what lipoproteins?

chylomicrons

21

What is the basic role of chylomicrons?

to take dietary triglycerides to the tissues where LPL removes them, leaving a chylomicron remnant which then takes cholesterol to the liver

22

What carries fatty acids from tissue to the liver?

albumin

23

What carries triglycerides from the liver to peripheral tissues?

VLDL

24

In what two ways is cholesterol excreted from the body?

directly or as bile salts produced in the liver

25

Cholesterol leaves the liver packaged in what sort of lipoprotein?

a VLDL

26

What happens to VLDL remnants?

- uptake by hepatic LDL receptors
- hydrolysis by HTGL to form LDL

27

To go from a nascent HDL to a mature HDL, what enzyme is required?

LCAT

28

What are the two possible fates of HDL?

- transfer of cholesteryl esters to VLDL by CETP
- direct liver uptake of cholesteryl esters by SR-B1 receptor

29

The ABC transporters are important for what liver function?

bile acid production for biliary lipid secretion

30

What is the function of ABCG5/G8?

transport of cholesterol into canaliculi in liver

31

What is the function of ABCB11?

transport of bile acids into canaliculi in liver

32

What is the function of ABCB4?

transport of phospholipids into canaliculi in liver

33

What is the function of ABCA1?

export of cholesterol and phospholipids to lipid-poor apolipoprotein A1

34

What is the function of ABCG1?

promote efflux of cellular cholesterol to HDL particles

35

ABCA1 and ABCG1 are critical to what lipid metabolic process?

reverse cholesterol transport via HDL

36

Reverse cholesterol transport is mediated by what lipoprotein?

HDL

37

What genetic defects would lead to high LDL cholesterol?

apoB, apoE, or LDL receptor defects

38

What genetic defects would lead to low HDL cholesterol levels?

apoA-1 or ABCA1

39

What genetic defects would cause VLDL or chylomicron triglyceride levels to be high?

defects in apoC-II (activator of LPL), LPL, or LCAT (esterifies cholesterol for packing into HDL)

40

What genetic defect would lead to high levels of chylomicron remnants and intermediate density lipoproteins?

apoE which is a hepatic LDL receptor for VLDL remnants and IDLs

41

What happens to plasma LDL that is not taken up by hepatic LDL receptors?

it migrates into vascular intima to be taken up by scavenger receptors

42

HDL is important and beneficial because it performs what function?

draws free cholesterol from cholesterol-rich cells

43

HDL is synthesized where?

in the liver and intestine

44

HDL decreases the among of cholesterol available for tissue deposition by doing what?

removing it from macrophages and promoting its return to the liver

45

When testing for lipoprotein disorders, you should measure ____ when?

serum lipids after a 10 hour fast

46

Primary hypertriglyceridemia is characterized by what?

high triglycerides

47

What is the most common form of primary hypertriglyceridemia?

familial hypertriglyceridemia of unknown genetic cause

48

What are two rare primary hypertriglyceridemias?

- familial lipoprotein lipase deficiency
- apoC-II deficiency

49

Familial hypercholesterolemia is due to what genetic defect?

the LDL receptor

50

When do cholesterol levels get elevated in someone with familial hypercholesterolemia?

at birth

51

When do triglyceride levels get elevated in someone with familial hypertriglyceridemia?

upon weight gain, aging, onset of diabetes, etc.

52

What are cutaneous xantomas?

cholesterol deposits seen in those with homozygous familial hypercholesterolemia

53

What is dysbetalipoproteinemia due to?

a defect in apoE causing a rise in chylomicrons and IDL-like particles

54

Tangier disease is due to what deficiency?

ABCA1, which is responsible for HDL formation