Active site is

Options

A. A part of carbohydrate molecule to which substrate binds
B. A cleft or crevice on DNA double helix
C. A cleft or crevice on enzyme into which sub strate fits
D. A part of anti body

Answer

**Step-by-Step Solution:**

1. **Understanding the Active Site**: The active site is a specific region on an enzyme where substrate molecules bind. It is crucial for the enzyme's function as it facilitates the chemical reaction.

2. **Identifying the Characteristics of the Active Site**: The active site is characterized as a cleft or crevice on the enzyme. This is where the substrate fits and interacts with the enzyme.

3. **Role of the Active Site**: When the substrate binds to the active site, it leads to a chemical reaction, allowing the enzyme to exhibit its catalytic activity.

4. **Analyzing the Options**:
- Option A: "A part of carbohydrate molecule" - Incorrect, as the active site is not a carbohydrate.
- Option B: "A cleft or crevice on DNA double helix" - Incorrect, as the active site is not related to DNA structure.
- Option C: "A cleft or crevice in an enzyme into which substrate fits" - Correct, as this accurately describes the active site.
- Option D: "A part of antibody" - Incorrect, as the active site is specific to enzymes, not antibodies.

5. **Conclusion**: The correct answer is Option C: "A cleft or crevice in an enzyme into which substrate fits."

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