Select the correct combination from the following .

Options

A. Metal ions irreversibly attached with apoenzyme - Activators .
B. Non-protein organic part attached tightly to the Apoenzyme - prosthetic group .
C. Protein organic part attached loosely to the apoenzyme - Coenzyme.
D. All of these .

Answer

To solve the question, we will analyze each of the given combinations related to enzymes and their components.

### Step-by-Step Solution:

1. **Understanding Apoenzyme**: An apoenzyme is the protein part of an enzyme that requires a cofactor to be active. Cofactors can be metal ions or organic molecules.

2. **Analyzing the First Combination**:
- The statement mentions "metal ions irreversibly attached with apoenzyme" and refers to it as an "activator".
- **Evaluation**: This is incorrect. Metal ions that are tightly bound to the apoenzyme are referred to as "prosthetic groups", not activators. Activators can be different types of molecules that enhance enzyme activity but are not necessarily tightly bound.

3. **Analyzing the Second Combination**:
- The statement refers to "non-protein organic part attached tightly to the apoenzyme" and calls it a "prosthetic group".
- **Evaluation**: This is correct. A prosthetic group is indeed a non-protein organic molecule that is tightly bound to the apoenzyme, contributing to the enzyme's function.

4. **Analyzing the Third Combination**:
- The statement mentions "protein organic part attached loosely to the apoenzyme" and labels it as a "coenzyme".
- **Evaluation**: This is incorrect. Coenzymes are organic molecules that are loosely associated with the apoenzyme and assist in enzyme activity, but they are not classified as protein organic parts.

5. **Analyzing the Fourth Combination**:
- The statement claims "all of these" combinations are correct.
- **Evaluation**: This is incorrect because not all the previous combinations are correct.

6. **Conclusion**:
- The only correct combination is the second one: "non-protein organic part attached tightly to the apoenzyme" is known as a "prosthetic group".

### Final Answer:
The correct combination is the second one: **Non-protein organic part attached tightly to the apoenzyme is known as a prosthetic group.**

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