What life is


No life without enzymes

In biological processes like photosynthesis that converts sunlight energy into sugar and respiration that converts sugar into useful cellular energy to sustain life, proteins have evolved that catalyze chemical reactions in very specific and very efficient ways. These proteins are called enzymes. Enzymes interact with reactants converting them into products. This conversion step may need input of energy to proceed or it can release energy to do work. Enzymes are the catalysts that control every biological process of life, with one exception; RNA molecules control and make proteins.

Many enzymes are membrane proteins. This means they are part of the natural barrier that separates the content of a cell from its surroundings. They control transport of molecules in and out of cells, receive and produce signals that cells use to communicate with each other, even if they are physically distant, convert light energy into chemical, and chemical energy into work, and they catalyze synthesis and degradation of many cellular structures making sure that old parts are replaced by new ones, or that invading microorganisms are destroyed before they can destroy the cell.

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 Copyright © 1999-2011 Lukas K. Buehler