bio

Homeoviscous adaptation

An organism retuning the lipid composition of its cell membranes to preserve the fluidity it needs as temperature or pressure changes. Both cold and high pressure compress the oily interior of a lipid bilayer toward a gel-like state — disastrous for anything that has to diffuse or be pumped across it. The answer is to build membranes with a higher proportion of kinked cis-unsaturated fatty acids, which pack badly on purpose, and that bad packing is what preserves fluidity. A deep-sea organism carries membranes tuned to its habitat depth, the way an instrument is tuned to a room.