Lipoprotein metabolism Flashcards
What are lipoproteins composed of
Lipid and apoprotein
What do lipoproteins do
Carry lipids around body via blood plasma
What are apoproteins
Proteins associated with lipoproteins
Functions of apoproteins
- Interact with cellular receptors
- Activate and inhibit enzymes involved in lipoprotein metabolism
In the intestine, what are triglycerides hydrolysed into and by what
Fatty acids and monoacylglycerols by lipase
Stage of intestinal uptake of dietary lipids
1) triglycerides hydrolysed into fatty acids and monoacylglycerols
2) fatty acids and monoacylglycerols enter through to mucosal cells
3) cholesterol also enters mucosal cells
4) Triacylglycerides (monoacylglycerols and fatty acids combine to form this) and cholesterol combine
5) this also combines with other lipids and proteins to form chylomicrons
6) chylomicrons go to lymph system
Where are chylomicrons secreted into
LYmph
How do chylomicrons reach plasma
Through thoracic duct
Where are chylomicrons transported to
adipose/muscle
Once in the blood, what does the chylomicron acquire
apoproteins C11 and E from HDL
why is C11 an important lipoprotein
Activates lipoprotein lipase (converts triglycerides to FFA and glycerol)
Where is lipoprotein lipase (LPL) found
Capillaries of endothelial cells
Why can FFA be delivered to muscle or other tissue
Because there are LPL found on capillaries of endothelial cells so if chylomicrons are in capillaries of tissue, then C11 on CM activates LPL and cause the TG’s in chylomicrons to b broken down to free fatty acids and glycerol which can be taken up by the tissue
How does dietary cholesterol get delivered to the liver
CM remnants
Does cholsetroll get taken up by cells? Why?
No because they don’t contain the right apoproteins to initiate cholesterol uptake by the cell
