Question

The organic compounds that are tightly attached to the protein part of an enzyme to make them catalytically active are called -------------------.

• A. prosthetic groups
• B. co-enzymes
• C. co-factors
• D. metal ions

Hint:

Organic helpers that remain tightly bound to the apoenzyme are called by a specific name.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept
A cofactor is a non-protein part that an enzyme needs to function. Cofactors can be prosthetic groups, coenzymes or metal ions.

Step 2: Distinguish
Prosthetic groups are organic compounds tightly bound to the protein part, such as haem in peroxidase and catalase. Coenzymes such as NAD are also organic but bind only loosely and temporarily.

Step 3: Conclusion
Metal ions are inorganic. So the tightly attached organic compounds are prosthetic groups.

Final Answer:
They are called prosthetic groups. \[ \boxed{\text{(A) }\text{prosthetic groups}} \]