Lipids Flashcards
What are triglycerides?
Glycerol carbon backbone with 3 fatty acids attached
Where are triglycerides synthesised?
Liver, adipose tissue and small intestine
What do phospholipids consist of?
Glycerol backbone with fatty acids plus a phosphate containing lipid
Lecithin and sphyngomyelin are examples of what?
Phosphate containing lipids
Phospholipids contain a polar and non polar group- what is this called?
Amphipathic molecules
Where are plasma phospholipids synthesised?
The liver
What makes up the hydrophobic tail of phospholipids?
Fatty acid
What is the stucture of cholesterol and what does it form part of?
Four ringed steroid nucleus- forms part of cell membranes
When is cholesterol found circulating in plasma?
When it is esterified to fatty acids
In the liver what is cholesterol synthesised from?
Acetate
What is the rate limiting enzyme in synthesis of chosterol?
B-hydroxyl b-methylglutaryl CoA reductase
How is cholesterol excreted?
It is metabolised to bile acids and excreted in bike
What are the 3 main functions of aplopoproteins?
1) the solubilise cholesterol esters and triglycerides
2) they regulate enzymes involved in lipid metabolism
3) bind to cell surface receptors
Why is ApoB100 and ApoB48 different?
In 48 a modification takes place in intestine cells - a stop is inserted into mRNA.
48 lacks LDL receptor
How many forms is there of ApoA and ApoC?
Two forms of ApoA 1 and 2
3 forms of C ApoC-I etc
What is the apopoliprotein and lipid associated with chylomicrons?
B48 and A, triglycerides
What is the apolipoprotein and lipid associated with VLDL
B100, C and E, triglycerides and cholesterol
What is the apolipoprotein and lipid associated with IDL
B100, C and E, triglycerides and cholesterol
What is the apolipoprotein and lipid associated with LDL?
B100, cholesterol
What does ApoC-II activate?
Lipoprotein lipase
What inhibits lipoprotein lipase?
ApoC-III
What is the apolipoprotein and lipid associated with HDL?
A,C,E cholesterol and phospholipids
What apolipoprotein is associated with receptor mediated transfer of cholesterol between tissues and plasma?
ApoE