Choose the true statement from the following

Options

A. Enzymes do not change the equilibrium of a reaction but are consumed in that reaction
B. Enzymes are active only in minute quantities and also at their optimum pH only
C. Enzymes increase the activation energy and speed up the rate of reaction
D. Enzymes are heat sensitive because they are proteins

Answer

To determine the true statement regarding enzymes, let's analyze the properties of enzymes step by step:

### 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 reactions to occur.

**Hint:** Remember that enzymes facilitate reactions without being consumed in the process.

### Step 2: Evaluate the Statements
1. **Enzymes change the equilibrium at the time of reaction.**
- This statement is false. Enzymes do not change the equilibrium of a reaction; they only speed up the rate at which equilibrium is reached.

2. **Enzymes are very larger in quantity.**
- This statement is misleading. Enzymes are typically present in small quantities relative to the substrates they act upon. They do not need to be in large amounts to be effective.

3. **Enzymes increase the activation energy.**
- This statement is also false. Enzymes actually lower the activation energy, making it easier for reactions to occur.

4. **Enzymes are heat sensitive.**
- This statement is true. Enzymes are proteins and their activity can be affected by temperature. High temperatures can denature enzymes, leading to a loss of function.

### Step 3: Conclusion
Based on the evaluation of the statements, the true statement is: **Enzymes are heat sensitive because they are made up of proteins.**

**Final Answer:** Option D: Enzymes are heat sensitive because they are made up of proteins.

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