AM L3.2 Lipid transport

Question 1

Triglycerides are…

Answer 1

free fatty acids attached to glycerol backbone

Question 2

….% of cholesterol is from endogenous synthesis

Answer 2

80%

only a small amount from the diet

Question 3

Name the endogenous synthesis pathway of cholesterol

Answer 3

HMGcoA Reductase pathway

Question 4

Cholesterol and triglycerides are soluble or insoluble?

Answer 4

insoluble

Question 5

How are cholesterol and TGs transported round the body?

Answer 5

Lipoproteins

Question 6

Names some lipoproteins (5)

Answer 6

Chylomicrons
Very low density lipoproteins (VLDL)
VLDL reminants
LDL
HDL

Question 7

Where do chylomicrons come from?

Answer 7

the diet

Question 8

Size of chylomicrons

Answer 8

100 - 1000nm

Question 9

chylomicrons transport chol and TG from…. to…… (via …… & ….)

Answer 9

GI tract to the tissues

via lymph and capillaries

Question 10

What happens to the chylomicrons?

Answer 10

Lipoprotein lipase (LPL) hydrolyses the triglycerides
Free fatty acids absorbed by tissues

Question 11

When LPL has acted on chylomicrons what is left?

where does it go?

Answer 11

Remnant chylomicrons

Transported to the liver and endocytosed where cholesterol is liberated

Question 12

What finally happens to dietary cholesterol that is liberated in the liver (4)

Answer 12

stored
oxidised to bile acids
secreted in bile unchanged
enters endogenous pathway

(Dietary chol has been transported via remnant chylomicrons to the liver and this is what it is used for)

Question 13

Size of VLDLs?

Answer 13

30-80nm

Question 14

VLDLs contain cholesterol that has come from where?

Answer 14

de novo synthesis

Question 15

VLDLs deliver cholesterol to…. and meanwhile

Answer 15

tissues

gradually decrease in size to from LDLs

Question 16

How is cholesterol returned to the circulation from tissues?

Answer 16

HDLs

Question 17

The higher the concentration of …. and the lower the concentration of ….. the greater the ATS risk

Answer 17

LDL

HDLs

Question 18

What is lipoprotein a?

Answer 18

an LDL like molecule.
Complex of apolipoprotein a bound to LDL via apolipoprotein B-100
Linked by disulphide bonds

Question 19

Function of lipoprotein A?

Answer 19

inhibits plasminogen

Question 20

Lipoprotein A is a risk factor for….

Answer 20

CVD

Question 21

What is the function of plasminogen?

Answer 21

to convert to plasmin (this catalyses fibrin –> soluble fibrin fragments)

Question 22

Obesity is a …… risk factor

Answer 22

multifactorial risk factor

increased incidence of doabetes, hypertension and high cholesterol