lipid metabolism

Question 1

describe the lipoprotein structure?
Hint: the outside is a monolayer of phospholipid and apolipoprotein membrane that contains…

Answer 1

triglycerides and cholesterol esters within. i.e. hydrophobic lipids

Question 2

cholesterol plays a role in the synthesis of ??? membranes, steroid hormones, bile acid

Answer 2

plasma membranes

Question 3

role of lipoproteins: carriers and distributors of hydrophobic or hydrophilic (?) lipids such as cholesteryl esters and TGs around the body

Answer 3

hydrophobic

Question 3

triglycerides play a role as a major source of ???

Answer 3

energy

Question 4

short chain Fatty acids can enter directly or indirectly (?) into bloodstream?

Answer 4

directly

Question 5

most dietary fat and all dietary cholesterol must be transferred into ??? to be absorbed

Answer 5

chylomicrons

Question 6

dietary fat becomes large TG droplets–> liver releases ??? which emulsify fat droplets into lipid membrane –> pancreatic lipase hydrolyses core TGs and free FAs + monoglycerides from the TGs

Answer 6

bile acids released

Question 7

free FAs and monoglycerides are absorbed by the GI tract and resynthesised into TGS which are then packaged into ??? and released into lymphatic system

Answer 7

chylomicrons

Question 8

endogenous pathway of TG absorption: VLDL –> IDL –> LDL & HDL –> ??? and this process (mostly) occurs in the liver

Answer 8

sdLDL

Question 9

chylomicrons are formed by the dietary ??? from exogenous lipid pathway

Answer 9

dietary TGs

Question 10

chylomicrons transport TGs and ???

Answer 10

cholesterol

Question 11

VLDL transports endogenous pathway TGs from ???

Answer 11

liver

Question 12

IDL transports endogenous pathway TGs and ???

Answer 12

cholesterol

Question 13

LDL delivers cholesterol to ??? in need

Answer 13

tissues/cells

Question 14

HDL picks up excess ??? from extra-hepatic cells, returns them to the liver

Answer 14

cholesterol

Question 14

measuring plasma lipid levels:
1. centrifuge to seperate plasma from leukocytes and erythrocytes
2. lipoproteins found in ??? plasma
3. VLDL, IDL, chylomicrons isolated from plasma via ultracentrifugation
4. fasting blood sample in pathology lab –> plasma TG, TC, LDL-C & HDL-C

Answer 14

watery

Question 14

TRUE or FALSE: apolipoproteins are cofactors for enzymes involved in lipid metabolism i.e. VLDL –> Lipoprotein lipase enzyme + apoCII
–> IDL +FAs

Answer 14

TRUE

Question 15

apolipoproteins can act as ??? sites for receptors on cell surfaces

Answer 15

recognition

Question 15

function of apolipoproteins: solubilise insoluble lipids and aid in ??? transport

Answer 15

plasma

Question 16

exogenous pathway of lipid metabolism step 1:
chylomicrons synthesised from dietary ??? + ??? in the intestine before being released into bloodstream

Answer 16

TGs and cholesterol

Question 17

Exogenous pathway of lipid metabolism step 2: once in the bloodstream, the chylomicrons are hydrolysed by ??? which releases FAs

Answer 17

glycoprotein lipase

Question 18

Exogenous pathway of lipid metabolism step 3: chylomicron fragments are taken up by liver and ??? + TGs form pools within the liver

Answer 18

cholesterol

Question 19

Endogenous pathway lipid metabolism step 1: once arrived at the liver, TG is resynthesised together with cholesterol into ???

Answer 19

VLDL

Question 20

Endogenous pathway lipid metabolism step 2: ??? hydrolyses core of VLDL to form IDL in bloodstream, releasing FAs.

Answer 20

lipoprotein lipase

Question 20

Endogenous pathway lipid metabolism step 3: IDL --> LDL which can be taken up by ??? receptor in liver or transported to extrahepatic tissue that is in need of TG and cholesterol.

Answer 20

LDL-receptor

Question 20

TRUE or FALSE: you can measure chylomicrons, VLDL and IDL using commercially available kits

Answer 20

FALSE: you cannot!

Question 20

HDL is the reverse cholesterol transport as it ??? extra cholesterol from extrahepatic tissue and brings back to liver

Answer 20

picks up extra cholesterol

Question 21

HMG-CoA Reductase converts 3-hydroxy 3-methyl glutaryl CoA to ??? acid

Answer 21

Mevalonic

Question 22

TRUE or FALSE: bile salts are made in the liver from cholesterol

Answer 22

TRUE

Question 22

what is the rate limiting enzyme for cholesterol synthesis?

Answer 22

HMG-CoA Reductase

Question 22

what is the cofactor for lipoprotein lipase?

Answer 22

Apolipoprotein CII

Question 22

the role of lipoprotein lipase (LPL) is to hydrolyse TGs in ??? as well as VLDL

Answer 22

chylomicrons

Question 23

lipoprotein lipase influences lipoprotein levels of all types and thus has an influence on ???

Answer 23

atherogenesis

Question 24

cholesteryl ester transfer protein transfers ??? from VLDL, IDL AND LDL TO HDL in exchange for Cholesteryl Esters from HDL

Answer 24

TGs

Question 25

what is the cofactor for Lecithin:Cholesterol Acyltransferase?

Answer 25

APO A-1

Question 25

what tries to equilibrate the core lipids between the different lipoprotein classes = remodelling of lipoproteins?

Answer 25

cholesteryl ester transfer protein

Question 25

Lecithin:Cholesterol Acyltransferase is a hepatically formed enzyme tuat esterifies ??? free cholesterol on HDL particles = reverse cholesterol transport

Answer 25

plasma free cholesterol

Question 26

normal sized LDL has more cholesterol per particle than sdLDL but sdLDL gets into arterial wall, becomes trapped and causes ???

Answer 26

atherosclerosis