Substrate Definition in Chemistry and Other Sciences

The definition of "substrate" depends on the context in which the word is used, particularly in the sciences.

Definitions of Substrate

Substrate (chemistry): A substrate is the medium in which a chemical reaction takes place or the reagent in a reaction that provides a surface for absorption. For example, in the fermentation of yeast, the substrate the yeast acts upon is sugar to produce carbon dioxide.

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Reagent Definition and Examples

By Anne Marie Helmenstine, Ph.D.

In biochemistry, an enzyme substrate is the substance the enzyme acts upon.

Sometimes the word substrate is also used as a synonym for the reactant, which is the molecule consumed in a chemical reaction.

Substrate (biology): In biology, the substrate may be the surface on which an organism grows or is attached. For example, a microbiological medium may be considered a substrate.

The substrate may also be the material at the bottom of a habitat, such as gravel at the base of an aquarium.

Substrate may also refer to the surface on which an organism moves.

Substrate (materials science): In this context, a substrate is a base on which a process occurs. For example, if gold is electroplated over silver, the silver is the substrate.

Substrate (geology): In geology, substrate is underlying stratum.