Question

Given the following lipid compositions of membranes leaflets (A) and (B). Which would most likely be the inner leaflet? The outer leaflet?
A = 35% phosphatidylcholine; 15% gangliosides; 5% cholesterol; 45% other lipids
B = 20% phosphatidylcholine; 15% phosphatidylserine; 65% other lipids

Answer 1

A is most likely the outer leaflet and B is inner leaflet.

Reason : Outer leaflet majorly consists of Phosphatidylcholine and Gangliosides. Phosphatidylserine is not present in outer leaflet. In the given choices, only A contains Phosphatidylcholine and Gangliosides. The composition of outer leaflet is similar to A in most eukaryotic species.

Similarly, Inner Leaflet majorly consists of Phosphatidylcholine and phosphatidylserine. Phosphatidylserine is usually not found in Outer membrane. So in the given choices, the composition of inner leaflet is similar to B in most eukaryotic species.

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