Lecture 6 Flashcards
Importance of transcription factors.
This is how genes become expressed.
Endogenous source of cholesterol.
De novo synthesis of Acetyl-CoA.
Statins.
They inhibit HMG-CoA reductase, thereby inhibiting cholesterol synthesis.
Bile acids.
Synthesized in the liver, secreted into the gallbladder, and then released into the intestine.
Bile acids.
Made from cholesterol in the liver, have a hydrophilic and hydrophobic phase, which allows for them to function as detergents. They are important signalling molecules: they can control the activity of transcription factors.
Degradation of lipids.
Occurs in the lumen of the intestine.
ACAT and MTP.
Enzymes that help assemble chylomicrons.
Lipoproteins are…
Covalent structures that allow interaction with many types of molecules.
Good and bad cholesterol.
The way cholesterol is being carried determines whether it is good or bad. Remember: lipoproteins carry cholesteryl esters. Note: the chemical moiety of both LDL and HDL are actually identical.
Bad cholesterol.
LDL.
Good cholesterol.
HDL.
Diet derived lipids.
Broken down in the stomach and then in the intestine; storage of triacylglycerol in the bloodstream and adipose tissue only occurs if there is an excess. Excess: chylomicrons repackage the lipoproteins into VLDL and the process repeats.
Apo A-1.
LCAT activator: responsible for turning cholesterol into cholesteryl esters.
Excess of cholesterol.
Turned into cholesteryl esters by LCAT; also ACAT.
Repackaged VLDL.
Same fate as dietary derived cholesterol.
Lipoprotein lipase (LPL).
Hydrolyzes the triglycerides inside the chylomicrons until only an LDL molecule remains.
Liver.
The inly organ in the body capable of getting rid of appreciable amounts of cholesterol.
Purpose of reverse cholesterol pathway.
To remove excess cholesterol.
When is the reverse cholesterol pathway activated?
When there is increased cholesterol in the periphery.
Periphery cell in relation to cholesterol.
Anything that is not a liver cell.
Where does lipoprotein assembly occur?
In liver cells and chylomicrons.
The liver makes…
VLDL and packages cholesterol to send it out, allowing the cholesterol to enter the blood.
Making bile acids.
Cholesterol is subjected to 4 transformations; cannot be converted back into cholesterol.
