Bacterial Membranes as Polyfunctional Systems
As they learned more about the physiology of bacteria, research workers were struck by the remarkable variety of functions performed by the membranes. Electron transfer in the respiratory chain, transformation of energy during photosynthesis, nitrogen fixation, the transport of ions and metabolites, and the synthesis of components of the cell wall, as well as of other substances, all take place in the membranes. The membrane apparatus of the bacterial cell is also concerned with such complex physiological processes as division, sporulation, and cyst formation. All functions which are distributed in plant and animal cells among specialized membrane structures (Nass, 1969; Broda, 1970) are connected in bacteria with the cytoplasmic membrane and the system of internal membranes. The main difficulty hindering our understanding of the way in which bacterial membranes function stems from the absence of morphological differentiation and the impossibility of ascribing a particular function to a particular structure of the membrane. However, this does not mean that membranes themselves do not include areas which have undergone specialization for the performance of particular functions, although there is yet very little evidence in this respect. At present, we must regard the functions of the bacterial cell membranes as a whole. It is not yet possible to determine experimentally the precise localization of these functions.
KeywordsRespiratory Chain Cytoplasmic Membrane Bacterial Membrane Teichoic Acid Internal Membrane
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