Difference Between Cholesterol and Cholesteryl Ester

Cholesteryl ester, a dietary lipid, is an ester of cholesterol. The ester bond is formed between the carboxylate group of a fatty acid and the hydroxyl group of cholesterol. Cholesteryl esters have a lower solubility in water due to their increased hydrophobicity.

1. Why is cholesterol converted to cholesteryl esters?
2. What do cholesterol esters do?
3. Why are cholesterol esters less polar than free cholesterol?
4. Where does cholesterol esterification occur?
5. Which lipoprotein is the main carrier of cholesterol?
6. How does reverse cholesterol transport work?
7. What is free cholesterol?
8. What is an ester bond?
9. Does cholesterol have glycerol?
10. Is cholesterol ester polar or nonpolar?
11. Why is cholesterol polar?
12. Is cholesterol a lipid?

Why is cholesterol converted to cholesteryl esters?

By converting cholesterol to cholesteryl esters more cholesterol can be packaged into the interior of lipoproteins. This vastly increases the capacity of lipoproteins, allowing for more efficient cholesterol transport through the blood stream.

What do cholesterol esters do?

Cholesterol esters are formed by acyl coenzyme A:cholesterol acyltransferase (ACAT) enzymes that play a key regulatory role in intestinal cholesterol absorption and provide core lipid for packaging of chylomicrons and hepatic-derived lipoproteins.

Why are cholesterol esters less polar than free cholesterol?

5. Cholesterol Esters. Cholesterol esters, i.e. with long-chain fatty acids linked to the hydroxyl group, are much less polar than free cholesterol and appear to be the preferred form for transport in plasma and as a biologically inert storage or de-toxification form to buffer an excess.

Where does cholesterol esterification occur?

Lecithin:cholesterol acyltransferase (LCAT) catalyzes the free cholesterol esterification reaction, which takes place mainly in HDL, thereby creating a gradient for unesterified cholesterol efflux from cells to HDL.

Which lipoprotein is the main carrier of cholesterol?

LDL carries the majority of the cholesterol that is in the circulation. The predominant apolipoprotein is B-100 and each LDL particle contains one Apo B-100 molecule. LDL consists of a spectrum of particles varying in size and density.

How does reverse cholesterol transport work?

Reverse cholesterol transport is a mechanism by which the body removes excess cholesterol from peripheral tissues and delivers them to the liver, where it will be redistributed to other tissues or removed from the body by the gallbladder. The main lipoprotein involved in this process is the HDL-c.

What is free cholesterol?

Cholesterol is the precursor of all steroid hormones, cholesterol esters, and bile acids, and is a component of the plasma membrane of cells. Total cholesterol consists of free cholesterol and cholesterol esters. Serum cholesterol is derived from the diet and is synthesized in the liver.

What is an ester bond?

Esters are a functional group commonly encountered in organic chemistry. They are characterized by a carbon bound to three other atoms: a single bond to a carbon, a double bond to an oxygen, and a single bond to an oxygen. ... Ester names are derived from the parent alcohol and the parent acid.

Does cholesterol have glycerol?

Dietary cholesterol is absorbed through the wall of the intestine and is packaged, along with triglyceride (glycerol ester-linked to three fatty acid chains), in chylomicrons.

Is cholesterol ester polar or nonpolar?

Cholesterol is very non-polar, except for the hydroxyl group attached to the first ring.

Why is cholesterol polar?

Most of the cholesterol molecule in non-polar and therefore associations with the non-polar fatty acid tails of the phospholipids. However, the hydroxyl group (-OH) on cholesterol carries a negative charge and therefore associates with the polar environment of water either inside the cell or outside.

Is cholesterol a lipid?

Cholesterol is a type of blood fat, and blood fats are known as lipids. Cholesterol and other lipids are carried in the blood attached to proteins, forming tiny spheres, or "parcels" known as lipoproteins. So, lipoproteins are lipids plus proteins.