Question

The plasma membrane is a structure common to all cell types and important in providing the cell with selective permeability. Identify one way that certain organisms can change the construction of their plasma membrane given changing environmental conditions (beside  biochemistry)

Answer 1

Modifications in membrane lipid composition play a major role in the adaptation of diverse organisms to specific environments and physiological circumstances.Acyl chain and molecular species restructuring in phospholipids are the most ubiquitous adaptations to environmental insult, on implicating this to membrane temperature, pressure, water activity, pH and salinity of membrane changes.

role of lipids in fine tuning membrane function are:

Signal transduction-In some cases, it is clear that the enzymes of lipid metabolism respond directly to variations in the physical environment in an apparently adaptive manner. It seems unlikely, however, that such direct effects can explain the totality of the adaptive capacity of organisms, especially given the evidence for the induction of desaturase synthesis in cold adaptation .

Adaptation thresholds-Interspecific comparisons of the Na+/K(+)-ATPase of fish collected at different depths indicate that species must be separated in depth by a distance corresponding to a pressure difference of 20 MPa before pressure adaptation is evident. A pressure of 20 MPa corresponds approximately to the maximum depth from which deep sea animals survive being brought to the surface. Assuming a dT/dP value of 0.23 , a 20 MPa change in pressure corresponds to a 5 degrees C change in temperature, which agrees well with the minimal temperature change required to elicit changes in the lipid composition of plasma membranes in kidney tissue of thermally-acclimating trout.Collectively, these observations suggest that the minimally effective stimuli for both temperature and pressure adaptation are similar.