The effectiveness of an enzyme is affected least by

Options

A. Temperature
B. Concentration of substrate
C. Concentration of enzyme
D. Original activation energy of the system.

Answer

To solve the question regarding which factor affects the effectiveness of an enzyme the least, we can analyze each option provided.

### Step-by-Step Solution:

1. **Understanding Enzyme Effectiveness**:
- Enzymes are biological catalysts that speed up chemical reactions by lowering the activation energy required for the reaction to occur.

2. **Analyzing Temperature**:
- Enzyme activity is influenced by temperature. Each enzyme has an optimum temperature at which it functions best. Deviations from this temperature can lead to decreased effectiveness.

3. **Analyzing pH**:
- Similar to temperature, the pH level also affects enzyme activity. Each enzyme has an optimum pH range. Extreme pH levels can denature the enzyme, reducing its effectiveness.

4. **Analyzing Substrate Concentration**:
- The concentration of substrate affects enzyme activity. As substrate concentration increases, the reaction rate increases until a maximum velocity is reached (Vmax). Beyond this point, adding more substrate does not increase the reaction rate significantly.

5. **Analyzing Enzyme Concentration**:
- The concentration of the enzyme itself affects its effectiveness. More enzyme molecules can bind to more substrate, thereby increasing the reaction rate.

6. **Analyzing Original Activation Energy**:
- The original activation energy of the system refers to the energy barrier that must be overcome for a reaction to occur. Enzymes work by lowering this activation energy. The original activation energy itself does not affect how effective the enzyme is once it has lowered the activation energy.

7. **Conclusion**:
- Among the factors analyzed, the original activation energy of the system is the one that affects the effectiveness of the enzyme the least. Therefore, the correct answer is option 4.

### Final Answer:
The effectiveness of an enzyme is affected least by the original activation energy of the system.

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