Which of these is false about enzymes?

Options

A. Nucleic acid which behave as enzymes are called ribozymes
B. Enzymes only catalyse the reaction and do not initiate it.
C. All enzymes are subjected to degradation at a temperature of more than `40^@C`
D. A reaction producing 200 molecules of `H_2CO_3` increases to 600,000 molecule in the presence of carbonic anhydrase.

Answer

To determine which statement about enzymes is false, we will analyze each statement provided in the question.

### Step-by-Step Solution:

1. **Analyze the First Statement:**
- **Statement:** Nucleic acids that behave as enzymes are called ribozymes.
- **Analysis:** This statement is true. Ribozymes are RNA molecules that can catalyze biochemical reactions, similar to protein enzymes.

2. **Analyze the Second Statement:**
- **Statement:** Enzymes only catalyze the reaction and do not initiate it.
- **Analysis:** This statement is also true. Enzymes speed up reactions (catalyze) but do not initiate them. They lower the activation energy required for the reaction to occur.

3. **Analyze the Third Statement:**
- **Statement:** All enzymes are subjected to degradation at a temperature of more than 40 degrees Celsius.
- **Analysis:** This statement is false. While some enzymes may denature (lose their functional shape) at high temperatures, many enzymes, especially those from thermophilic organisms, can function at temperatures above 40 degrees Celsius. Therefore, not all enzymes degrade at this temperature.

4. **Analyze the Fourth Statement:**
- **Statement:** A reaction producing 200 molecules of H2CO3 increases to 6 lakh molecules in the presence of carbonic anhydrase.
- **Analysis:** This statement is true. Carbonic anhydrase is an enzyme that significantly increases the rate of conversion of carbon dioxide and water into carbonic acid, demonstrating the catalytic power of enzymes.

### Conclusion:
The false statement among the options is the third statement: "All enzymes are subjected to degradation at a temperature of more than 40 degrees Celsius."

### Final Answer:
The false statement about enzymes is: **"All enzymes are subjected to degradation at a temperature of more than 40 degrees Celsius."**

---