Cells must maintain an appropriate level of fluidity across their membranes. Hot temperatures lead to greater membrane fluidity. What might you then expect to find regarding the membrane composition of bacteria from very hot environments

Thermophilic bacterial are rich in large quantity of thermophilic lipids in the cell membranes. This components made the membrane to be impermeable at high temperature, and therefore a good adaptation for the hot environment.

At high temperature,proton permeability increase, sodium permeability also increases but to a ;lesser extent, but Lipid is independent of this temperature rise.

Hence, these organisms rely on the less permeable Na+ for the maintenance of high sodium motive force.it is the energy derived from this that the cell membrane needs to maintain stability, coupe  with the lipid content.

Explanation:

a "theory" a suggestion that is not 100 % accurate, or a figure. some people say its a theory because they of all the passed theory's about one subject. it depends sometimes theory might be accurate and sometimes they are.