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 regarding the correct combination of terms related to enzymes, we will analyze each option step by step.

### Step 1: Understanding the Terms
- **Apoenzyme**: This is the protein part of an enzyme, which requires a cofactor to be active.
- **Cofactor**: This can be a metal ion or an organic molecule that assists in enzyme activity.
- **Prosthetic Group**: A non-polypeptide unit that is tightly and permanently attached to an enzyme.
- **Coenzyme**: An organic molecule that is loosely attached to an enzyme and assists in its function.

### Step 2: Analyzing Each Option
1. **Metal ions irreversibly attached with apoenzyme**:
- This statement is incorrect. Metal ions are typically tightly bound to the enzyme but are not considered irreversibly attached. They are classified as prosthetic groups.

2. **Non-protein organic part attached tightly to apoenzyme**:
- This statement is correct. Non-protein organic parts that are tightly bound to the apoenzyme are indeed called prosthetic groups.

3. **Protein Organic Part Attached Loosely to Apoenzyme**:
- This statement is incorrect. The loosely attached organic molecules are known as coenzymes, and they are not protein parts.

4. **All of these**:
- This option is incorrect because not all the statements provided are correct.

### Conclusion
Based on the analysis, the correct combination is:
- The second option is correct: "Non-protein organic part attached tightly to apoenzyme is called Prosthetic Group."

### Final Answer
The correct answer is **Option 2**.

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