Lipoproteins

Question 1

What are lipoproteins made up of

Answer 1

Apoproteins and lipids

Question 2

Examples of lipids that make lipoproteins

Answer 2

TAG/TG/Fat Cholesterol, Cholesteryl Esters, Phospholipids

Question 3

Two functions of lipoproteins

Answer 3

Increase the solubility of their lipid components in plasma

Transport their lipid components between different tissues

Question 4

What is found in the core of lipoproteins

Answer 4

TAGs and cholesteryl esters

Question 5

What is found on the surface of lipoproteins

Answer 5

Apoproteins, phospholipids and cholesterol

Question 6

What are the two by which lipoproteins can be separated

Answer 6

Based on density and electrophoretic mobility

Question 7

Which technique is used to separate lipoproteins

Answer 7

ultracentrifugation

Question 8

List the lipoproteins in increasing order of density

Answer 8

Chylomicrons
VLDL
LDL
HDL

Question 9

List the lipoprotiens in order of decreasing mobility

Answer 9

alpha-lipoproteins (HDL)

2. Pre β-lipoprotein (VLDL)
3. β-lipoprotein (LDL)
4. Chylomicrons (remain at the origin)

Question 10

How many classes of apoproteins are there

Answer 10

5 classes (A,B,C,D,E)

Question 11

Apo B-48 is associated with which lipoprotein

Answer 11

Chylomicrons

Question 12

Apo B-100 is associated with which lipoprotein

Answer 12

VLDL and LDL

Question 13

Apo A is associated with which lipoprotein

Answer 13

HDL

Question 14

Which apoprotein is the activator for lipoprotein lipase

Answer 14

Apo C-II

Question 15

Which apoprotein is the activator for LCAT

Answer 15

Apo A-I

Question 16

Which apoproteins are reognition sites for cell-surface receptors

Answer 16

Apo E

Apo B-100

Question 17

How many isomers does Apo E have

Answer 17

Three isoforms (E-2, E-3 and E-4)

Question 18

What deficiency causes (type III hyperlipoproteinemia

Answer 18

decreased clearance of CM remnants & IDL because they only have Apo E-2 which binds poorly to receptors

Question 19

Expression of Apo E-4 only isoform, suggest and increased susceptibility to which disease

Answer 19

Alzheimers

Question 20

Newly synthesized nascent chylomicrons have which apoproteins

Answer 20

Apo B-48

Question 21

Which two apoproteins from HDL are transferred to the nascent chylomicron

Answer 21

Apo C-II and Apo E

Question 22

At which point during chylomicron metabolism is the Apo C-II returned to the HDL

Answer 22

After the TAG portion is removed in the capillaries and bbbefore it enters the liver

Question 23

What is the function of microsomal TAG transfer proteins (MTP)

Answer 23

Loads lipids onto the apoproteins to make chylomicron particles

Question 24

Where are chylomicrons packaged into secretory vesicles

Answer 24

In the golgi

Question 25

Chylomicrons are secreted into what structure for transport into the thoracic duct

Answer 25

Lacteals

Question 26

After leaving the thoracic duct, nascent chylomicrons enter the blood circulation through which vessel

Answer 26

Left subclavian vein

Question 27

which enzyme is needed for chylomicron remnant metabolism

Answer 27

Hepatic lipase

Question 28

Which form of chylomicrons are intermediate density chylomicrons

Answer 28

Nascent chylomicrons

Question 29

Where are chylomicrons assembled

Answer 29

In the intestinal mucosa

Question 30

Which apoprotein is the major apoprotein and where is it synthesized

Answer 30

RER

Question 31

Liproprotein lipase is present in what of most tissues

Answer 31

the capillary walls of most tissues

Question 32

Even though liproprotein lipase is found in most tissues, which tissues is it predominantly found

Answer 32

adipose, cardiac and skeletal muscle

Question 33

Which tissue has a higher Km for TAG (cardiac muscle or adipose tissue)

Answer 33

Adipose tissues (becomes more active after a meal)

Question 34

Which hormone stimulates synthesis of lipoprotein lipase and its transport to the luminal surface of the capillary

Answer 34

Insulin

Question 35

What is the basis for hyperlipidemia in diabetes mellitus

Answer 35

lack of insulin leads to decreased clearance of lipoproteins due to decreased Lipoprotein lipase

Question 36

Deficiency of what causes type I hyperlipoproteinemia

Answer 36

lipoprotein lipase

Question 37

nascent TAG rich VLDL particles are secreted by which organ

Answer 37

liver

Question 38

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

Answer 38

transfers cholesteryl esters from HDL to VLDL in exchange for TAG

Question 39

What molecule is lost from IDLs thus converting them to LDLs

Answer 39

Apo E

Question 40

Which two tissues take cholesterol from LDL to make steroid hormones

Answer 40

Gonads and adrenal cortex

Question 41

Which receptors do LDLs bind to in the liver and EHT to get endocytosed

Answer 41

Apo B-100 E receptor

Question 42

A deficiency in LDL receptors causes which disease

Answer 42

familial hypercholesterolemia

Question 43

what is responsible for the lowering of endosomal pH during LDL metabolism

Answer 43

proton pumping by endosomal ATPase

Question 44

What does the reduction in pH in endosomes during LDL metabolism cause

Answer 44

separation of LDL from its receptor

Question 45

What disease is caused when LDL contents are not degraded by lysosomal enzymes during LDL metabolism

Answer 45

Wolman’s disease

Question 46

Which layer of blood vessels does LDL usually accumulate, leading to atherosclerosis

Answer 46

Tunica intima

Question 47

Which cholesterol is "bad"

Answer 47

LDL cholesterol

Question 48

Which organs secrete HDLs

Answer 48

Liver and intestines

Question 49

A deficiency in ABCA1 (ATP binding Cassette transporter A1 results in which disease

Answer 49

Tangier disease

Question 50

Which enzyme helps to added unesterified cholesterol to HDL

Answer 50

LCAT (lecithin:cholesterol acyltransferase)

Question 51

what activates LCAT (lecithin:cholesterol acyltransferase)

Answer 51

Apo A-I

Question 52

Mature HDL exchanges cholesteryl ester for TAG with which molecules

Answer 52

VLDL, IDL, LDL and chylomicrons

Question 53

What mediates the transfer of TAG to HDL from molecules such as LDL

Answer 53

CETP (cholesteryl ester transfer protein)

Question 54

Three functions of HDL

Answer 54

Transports cholesterol from extrahepatic tissues to the liver Reservoir of apoproteins in circulation Inverse relationship between plasma HDL level & risk of atherosclerosis & myocardial infarction

Question 55

what are the 5 types of hypolipoproteinemias

Answer 55

Abetalipoproteinemia Familial hypobetalipoproteinemia Familial alpha lipoprotein deficiency/ Tangier’s disease Familial LCAT deficiency Fish eye disease

Question 56

what are the 6 types of hyperlipoproteinemias

Answer 56

Type I (Familial lipoprotein lipase deficiency Type II(a) (Familial hypercholesterolemia) Type II(b)/ Familial combined hyperlipidemia Type III (Familial dysbetalipoproteinemia/ Broad beta disease) Type IV (Familial hypertriglyceridemia) Wolman’s disease (Cholesterol ester storage disease)