Lipid transport

Question 1

2% of lipids are carried in the blood bound to ……

Answer 1

Albumin

Question 2

What are the components of a lipoprotein?

Answer 2

Peripheral apolipoproteins, integral apolipoproteins, phopholipid monolayer and a cargo

Question 3

Which lipoprotein classes carry TAGs?

Answer 3

Chylomicron and VLDL

Question 4

Which lipoprotein classes carry cholesterol esters?

Answer 4

IDL, HDL and LDL

Question 5

What are the roles of apolipoproteins? (2)

Answer 5

• Packaging water insoluble lipid

- Co-factor for enzymes and ligands for cell surface receptors

Question 6

apoB is found on which three lipoproteins?

Answer 6

VLDL, IDL and LDL

Question 7

apoA1 is found on which lipoprotein?

Answer 7

HDL

Question 8

apoC is found on chlyomicrons and VLDL. What does it bind to?

Answer 8

Lipoprotein lipase

Question 9

Where do chylomicrons and VLDL release their cargo?

Answer 9

Muscle and adipose tissue

Question 10

What is the issue of LDL’s having a long half-life?

Answer 10

They are much more susceptible to oxidative damage. When taken up by macrophages this can lead to athreosclerosis.

Question 11

Which apolipoprotein found on LDL’s acts a ligand for LDL uptake receptors?

Answer 11

apoB-100

Question 12

How are LDL’s formed?

Answer 12

Through the degradation of VLDL’s and then IDL’s

Question 13

Where are HDL’s synthesised?

Answer 13

The liver

Question 14

The ABCA1 protein protein within cells facilitates the transfer of HDL to cholesterol. True or false?

Answer 14

False. The protein helps cholesterol transfer to the HDL.

Question 15

Where is mature HDL taken up?

Answer 15

The liver

Question 16

What is hypercholesterolaemia?

Answer 16

It is high levels of cholesterol in the blood

Question 17

What are the clinical signs of hypercholeestrolaemia?

Answer 17

• Xanthelasma -> yellow patches on eyelids
• Tendon Xanthelasma -> Tendon nodules
• Corneal arcus -> Obvious white circles around the eyes

Question 18

How are foam cells formed?

Answer 18

When macrophages engulf oxidised LDL

Question 19

Where do foam cells accumulate to form atherosclerotic plaques?

Answer 19

The intima of blood vessel walls

Question 20

What is the role of LDL’s?

Answer 20

To transport cholesterol synthesised in the liver to tissues

Question 21

What is the role of HDL’s?

Answer 21

Transport of excess cholesterol from cells to the liver for disposal as bile salts and to cells requiring additional cholesterol

Question 22

What is the role of chylomicrons?

Answer 22

To transport TAGs from the small intestine to tissues

Question 23

What is the role of VLDL?

Answer 23

Transport of TAGs synthesised in the liver to tissues

Question 24

Bile sequestreants are used as a treatment of hyperlipoproteinaemis. How do they work?

Answer 24

They bind bile salts in the GI tract. This forces the liver to produce more bile salts using up more cholestrol

Question 25

How many classes of hyperlipoproteinaemias are there?

Answer 25

5 classes

Question 26

Why do lipids require to be transported in the blood bound to a carrier?

Answer 26

Because they are insoluble