Mention the nature of the unit membrane of robertson
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According to Robertson, the unit membrane consisted of a bimolecular lipid leaflet sandwiched between outer and inner layers of protein organized in the pleated sheet configuration.
Such an arrangement was presumed to be basically the same in all cell membranes.
In the late 1950s, electron microscopy provided additional information about the structure of the plasma membrane.
J. D. Robertson was a pioneer in this area, showing that membranes fixed with osmium tetroxide revealed a characteristic tri-laminar appearance consisting of two parallel outer dark (osmiophilic) layers and a central light (osmiophobic) layer (Fig. 15-6).
The osmiophilic layers typically measured 20-25 Å (2.0-2.5nm) in thickness and the osmiophobic layers measured 25-35 Å (2.5-3.5 nm), yielding a total thickness of 65-85 Å (6.5-8.5 nm). This value compared favorably with the thickness predicted on the basis of chemical studies.
Such an arrangement was presumed to be basically the same in all cell membranes.
In the late 1950s, electron microscopy provided additional information about the structure of the plasma membrane.
J. D. Robertson was a pioneer in this area, showing that membranes fixed with osmium tetroxide revealed a characteristic tri-laminar appearance consisting of two parallel outer dark (osmiophilic) layers and a central light (osmiophobic) layer (Fig. 15-6).
The osmiophilic layers typically measured 20-25 Å (2.0-2.5nm) in thickness and the osmiophobic layers measured 25-35 Å (2.5-3.5 nm), yielding a total thickness of 65-85 Å (6.5-8.5 nm). This value compared favorably with the thickness predicted on the basis of chemical studies.
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