What is the Difference Between Ergosterol and Cholesterol?

Ergosterol and cholesterol are both sterols found in eukaryotic organisms, but they have distinct differences in their structure, function, and distribution. The main differences between ergosterol and cholesterol are:

1. Origin and distribution: Ergosterol is the major sterol found in the plasma membranes of yeast and fungi, while cholesterol is the major sterol found in the plasma membrane of animals.
2. Structure: Ergosterol has an additional double bond in a ring of the steroid nucleus and a double bond and an extra methyl group in the alkyl side chain. Cholesterol does not have an additional double bond in a ring of the steroid nucleus, a double bond, or an extra methyl group on the alkyl side chain.
3. Condensing effects: Ergosterol has a weaker condensing effect on fully saturated lipids compared to cholesterol. Ergosterol slightly thins POPC and DOPC bilayers, while cholesterol has a significant thickening effect on all lipids. Moreover, ergosterol positions itself closer to the bilayer/water interface, unlike cholesterol.

In summary, ergosterol and cholesterol are two different sterols found in eukaryotes with distinct structures, functions, and distribution. Ergosterol is primarily found in yeast and fungi, while cholesterol is found in animal cells. Their differences in structure lead to varying effects on membrane properties, such as condensing effects and positioning within the bilayer.

Comparative Table: Ergosterol vs Cholesterol

Here is a table comparing the differences between ergosterol and cholesterol:

Ergosterol is the major sterol found in the plasma membrane of yeast and fungi, while cholesterol is the major sterol found in the plasma membrane of animals. Ergosterol has an additional double bond in a ring of the steroid nucleus and a double bond and an extra methyl group on the alkyl side chain, whereas cholesterol does not have these features. Ergosterol has a less significant condensing effect on membrane thickness compared to cholesterol.