Substrates are what?

Substrates are what?

• A. Reactants (correct)
• B. Products
• C. Catalysts
• D. Inhibitors

Answer: (A)

Substrates are the starting materials of an enzyme-catalyzed reaction; these are the molecules that bind to the enzyme’s active site and are transformed into products. In other words, substrates are the reactants that undergo chemical change during the reaction. For example, lactose is the substrate for the enzyme lactase, which converts it into glucose and galactose. They are not products—the molecules formed after the reaction—nor are they catalysts, which speed up reactions without being consumed, or inhibitors, which decrease enzyme activity by binding to the enzyme.

Substrates are the starting materials of an enzyme-catalyzed reaction; these are the molecules that bind to the enzyme’s active site and are transformed into products. In other words, substrates are the reactants that undergo chemical change during the reaction. For example, lactose is the substrate for the enzyme lactase, which converts it into glucose and galactose. They are not products—the molecules formed after the reaction—nor are they catalysts, which speed up reactions without being consumed, or inhibitors, which decrease enzyme activity by binding to the enzyme.