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feedback

Definition

Those elements of a control system or homeostatic mechanism linked by reciprocal influences, so that the source or input is continuously modified by a product of the process in order to maintain the necessary degree of constancy; a feedback loop may be of negative or positive effect, for example, as a method of biochemical pathway control, where a pathway of successive enzymes leads to the formation of an important metabolite. The amount of the metabolite present may control the activity of one of the early enzymes in the pathway; the metabolite influences and thus inhibits (negative) or increases (positive) the activity of an earlier enzyme.

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