In enzymatic reactions, which statement about substrates is true?

In enzymatic reactions, which statement about substrates is true?

• A. The reactant in an enzymatic reaction
• B. The product formed
• C. A catalyst that speeds up the reaction
• D. An enzyme's cofactor

Answer: (A)

Substrates are the molecules that bind to the enzyme’s active site and undergo chemical transformation during the reaction. They are the reactants in enzymatic steps, becoming products as the enzyme lowers the activation energy and facilitates the change. The product is what results after the reaction, not the molecule the enzyme acts on. A catalyst that speeds up the reaction is the enzyme itself, not the substrate, and a cofactor is a nonprotein component that helps some enzymes function, rather than being the substrate. So identifying the substrate as the reactant in an enzymatic reaction captures its role in the process.

Substrates are the molecules that bind to the enzyme’s active site and undergo chemical transformation during the reaction. They are the reactants in enzymatic steps, becoming products as the enzyme lowers the activation energy and facilitates the change. The product is what results after the reaction, not the molecule the enzyme acts on. A catalyst that speeds up the reaction is the enzyme itself, not the substrate, and a cofactor is a nonprotein component that helps some enzymes function, rather than being the substrate. So identifying the substrate as the reactant in an enzymatic reaction captures its role in the process.