The reactant in an enzyme-catalysed reaction is called the

Options

A. hormone
B. substrate
C. cofactor
D. inhibitor

Answer

To answer the question, "The reactant in an enzyme-catalysed reaction is called the," we can follow these steps:

### Step 1: Understand the Role of Enzymes
Enzymes are biological catalysts that speed up chemical reactions in living organisms. They do this by lowering the activation energy required for the reaction to occur.

**Hint**: Remember that enzymes are proteins that facilitate biochemical reactions.

### Step 2: Identify the Reactants
In any chemical reaction, the substances that undergo change are known as reactants. In the context of enzyme-catalysed reactions, these reactants are the molecules that the enzyme acts upon.

**Hint**: Think about what happens to the molecules before they are transformed by the enzyme.

### Step 3: Define the Specific Term
The specific term used to describe the reactants in an enzyme-catalysed reaction is "substrate." The substrate is the substance that binds to the enzyme's active site and is transformed into products.

**Hint**: Recall that the substrate is the starting material in the reaction that the enzyme modifies.

### Final Answer
The reactant in an enzyme-catalysed reaction is called the **substrate**.