Lipids Flashcards
What type of lipids are there?
1) Simple lipids (fatty acids; triacyeglycerols di mono; waxes)
2) Compound lipids (phospholipids, glycolipids, lipoproteins)
3) Derived lipids (derivates such as sterols and straight chain alcohols)
How do larger lipids travel through circulation and why are these necesarry?
via chylomicrons, HDL, LDL’s and VLDL. These are necessary as they are hydrotrophic, they are water soluble and help the lipids transport.
What are lipids stabilised by?
polar bile salts
Where do the Micelles interact?
at the brush boarder
Where does the lipid part of the micelle diffuse?
out of the micelles and into the enterocytes on a concentration gradient
What happens after lipid absorption?
re-formation or re-esterification of triacylglycerols, phosphatiolylcholine and cholesteryl esters take place.
What do short chain fatty acids attach to for transport to other tissues and blood?
albumin
What are the primary form of lipoproteins formed from exogenous lipids?
Chylomirons
What other lipoproteins that transport endogenous lipids from tissue to tissue?
VLDL’s, LDL’s, and HDL’s
What are VLDL’s made up of?
high levels of triaylglycerol (TAG) an less protein and cholesterol
What are LDL’s made up of?
Less triacylglycerol, higher protein and highest cholesterol
What are HDL’s made up of?
the lowest amount of triacylgycerol, highest protein and intermediate cholesterol. (which delivers back to the liver)
What are Apolipoproteins?
they are the protein component of the lipoproteins that stabilise the lipoproteins as they circulate in the blood.
What makes apolipoproteins so important to lipoproteins?
they allow lipoproteins to be recognised by specific cell receptors and stimulates certain enzymatic reactions.
In a sample of blood under a microscope, what is it that can be seen floating around in the blood plasma?
chylomicrons
What is the distribution process of lipids in the body?
- the lipid leaves the enterocyte in the form of chylomicrons, which then undergo conversion to chylomicron remnants.
- lipoproteins first appear in the lymphatic vessels of the abdominal region then enter the blood stream at a slow rate.
how long after eating a fatty meal do chylomicrons still enter the blood stream?
up to 14 hours after eating
when is the blood plasma lipid level at its peak?
30 minutes to 3 hours after eating
What accounts for the milking appearance of fats? (turbidity)
the large triacylglycerol laden chylomicrons
what are chylomicron remnants?
small particles left after lipolytic action that is richer in cholesterol rather than triacylglycerols
what is a liver cell endocytosis?
the removal of chylomicron remnants from the blood stream
What is the main component of pile and what generates it?
Cholesterol is the main component of bile and the liver is what generates it
What types of cells in the body have the ability to oxidise free fatty acids and hydrolise diacylglycerols for energy?
Muscle cells
What type of fat deposits to aerobically trained muscle contain?
triacylglycerols
What are the 4 action of the liver in lipid metabolism?
1) synthesis of bile salts for digestion and absorption of dietary fats
2) synthesis of lipids from non-lipid precursors, i.e glucose and amino acids
3) can take up and catabolise exogenous lipids or use these for re-synthesis of other lipids
4) The synthesis of fatty acids, triacylglycerols, VLDL, HDL, LDL, glycerol, cholesterol, monoacylglycerols and diacylglycerols.
Chylomicron remnant cholesterol and cholesteryl esters may be (3):
a) converted to bile salts and secreted in the bile
b) secreted into the bile as neutral sterols
c) incorporated into VLDL or HDL and released into plasma
What are the roles of an adipocyte in lipid metabolism? (4)
- it is a major storage site
- fat constitutes for 85% of the adipose cell
- insulin increase the availability and uptake of fatty acids by stimulating lipoprotein lipase.
- cellular glucose provides the source of glycerophosphate for re-estification with the fatty acids from triacylglycerols.
