2. Properties of extremophiles

The concept of extremophilia, unlike that of resistance to extreme conditions, implies that the entire cellular machinery is adapted to extreme conditions, and that cells function optimally under these conditions. However, not every cell component necessarily functions optimally under the conditions of the external environment. Cells are able to control intracellular conditions to a certain extent, for parameters such as osmolarity. As a result, the intracellular pH of alkaliphilic strains will be lower than that of the external environment, and vice versa for acidophilic species. On the other hand, for certain parameters, such as temperature and pressure, the conditions of the external environment are imposed on the cells as a whole, including membranes, the internal environment and all cellular constituents. These cellular constituents must not only be stable under these conditions, but...