Enzyme is similar to catalyst because it is:

Options

A. required in small quantity
B. proteinaceous
C. Specific to pH
D. specific to substrate

Answer

**Step-by-Step Solution:**

1. **Understanding Enzymes and Catalysts**:
- Both enzymes and catalysts are substances that speed up chemical reactions. Enzymes are biological catalysts, while catalysts can be inorganic or organic compounds.

2. **Requirement in Small Quantities**:
- Both enzymes and catalysts are effective in very small amounts. They do not get consumed in the reaction and can be reused multiple times. This is a key similarity.

3. **Functionality**:
- Enzymes and catalysts both facilitate reactions in both the forward and reverse directions. They lower the activation energy required for the reaction to proceed.

4. **Nature of Enzymes**:
- Enzymes are proteinaceous, meaning they are made up of proteins. This is a significant difference from many catalysts, which can be inorganic compounds.

5. **Specificity**:
- Enzymes are highly specific to their substrates (the molecules they act upon), meaning each enzyme typically catalyzes only one specific reaction. In contrast, many catalysts are not specific and can catalyze multiple reactions.

6. **Sensitivity to Conditions**:
- Enzymes are sensitive to environmental conditions such as pH and temperature, which can affect their activity. Catalysts, on the other hand, can often function over a wider range of conditions.

7. **Conclusion**:
- The primary similarity between enzymes and catalysts is that both are required in small quantities to speed up reactions. Other characteristics, such as being proteinaceous, specificity, and sensitivity to pH, highlight their differences.

**Final Answer**: Enzyme is similar to catalyst because it is required in small quantities to speed up reactions.

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