how does temperature affect the permeability of the plasma membranesWatch this thread
TBH I have not considered this b4, so pls bear with me but I will need to conjecture/hypothesize.
My first thought would be that the unit membrane is said to be "fluid-mosaic", which immediately tells us that the glycoproteins and the proteins [at least the non-integral ones] can move about a little; I would extend this well-established interpretation of the nomenclature and say that this flexibility would allow permeability, in conjunction with the fact that the phospholipid bilayer will be more fluid [almost melts] at a higher temp [as lipids in general do cos of relatively low melting point], thus permitting substances to pass through it more easily.
I could be completely wrong tho -
how does it affect the proteins which then make the membrane more permeable?
In high temperature the cell membrane becomes more fluid. This gives a bigger chance for some materials to get in or out through the spaces made between the phospholipid molecules as a result of this increased fluidity. There are likely other issues arising from temperature, but this is a good one.