Lipids Flashcards
Are lipids soluble in water?
No
What are lipids essential for?
membrane integrity and biogenesis
How are non polar lipids transported?
In lipoproteins e.g. HDL, LDL
Is the lipoprotein core hydrophobic or hydophilic, and what does it contain?
Hydrophobic, contains esterified cholesterol triglycerides
Is the lipoprotein coat hydrophobic or hydrophilic?
Hydrophilic
What is the lipoprotein coat a monolayer of?
Amphipathic cholesterol, phospholipids and one or more apoproteins
What are the 4 main lipoproteins?
HDL, LDL, VLDL and Chylomicrons
What are the 3 parts of the life cycle of Apo-B containing lipoproteins?
assembly, intravascular metabolism and receptor mediated clearance
Where do Apo-B containing lipoproteins deliver triglycerides?
To muscle for ATP biogenesis, and to adipocytes for storage
Where are chylomicrons formed?
intestinal cells
What do chylomicrons deliver and by what pathway?
dietary triglycerides, by exogenous pathway
Where is VLDL formed?
Liver cells
What does VLDL transport?
Triglycerides synthesised in the endogenous pathway
What protein do Apo-B containing lipoproteins contain?
NPCILI
How does chylomicron exit the enterocyte?
exocytosis following addition of second apoprotein
What is the chlyomicron carried in after it leaves the enterocyte?
Lymph via the thoracic duct
What are free fatty acids in VLDL derived from?
adipose tissue and de novo synthesis
What activates VLDL?
transfer of apoCII from HDL particles
What does ApoC11 facilitate the binding of?
Chylomicrons and VLDL to LPL
What does LPL hydrolyse?
core triglycerides to free fatty acids and glycerol which enter tissues
Particles depleted of triglycerides are termed what?
Chylomicron and VLDL remnants
What are these remnants further metabolised by?
hepatic lipase in the liver
What are they then cleared by?
Receptor mediated enterocytes into hepatocytes
What does released cholesterol cause?
Inhibition of HMG-CoA reductase
What is LDL oxidised to?
Atherogenic OXLDL
What do monocytes migrate across the endothelium to and what do they become?
Intima, become macrophages
What are these macrophages converted to?
Cholesterol laden foam cells which form a fatty streak
What is then released?
Inflammatory substances
What is formed?
Atheromatous plaque consisting of lipid core (dead foam cells) and fibrous cap (product of dead foam cells)
What is the only organ with the capacity to eliminate cholesterol?
Liver
Where is HDL mainly formed?
Liver
What type HDL matures into what type?
pre-B-HDL to spherical alpha-HDL
What does the mature form of HDL accept?
excess cholesterol from plasma membrane of cells (which it delivers to liver - reverse cholesterol transport)
Subset of what is associated with increased risk of ischaemic heart disease?
Subset of type IIa hyperliproteinaemia
What is the mediator or transfer of esterin plasma?
CETP
