Organisms that Function with Small Numbers of Molecules

Abstract

Escherichia coli and other bacteria are said to be the lowest forms of life in the biological world. Nevertheless, bacteria are magnificent organisms that can recognize the ambient environment, propagate ambient information into its body, and (in the case of most bacteria, at least…) possess the capacity to swim toward a more favorable environment; these are systems that no man-made machine could even hope to imitate. This complex machinery is constructed in an extremely small unit of space about a femtoliter. Because this organism is so small, its proteins function in far smaller numbers than seen in other organisms (on the order of about 100 protein molecules involving methylation and demethylation, and 1000 phosphorylated protein molecules work in a cell). Let us gain an understanding of the chemotaxis and motility of bacteria through the following conversation between a mother and her daughter.