Prosthetic Groups in Enzyme Function — NEET Biology
✅ Asked in NEET 2025Which one of the following enzymes contains ‘Haem’ as the prosthetic group?
Which one of the following enzymes contains ‘Haem’ as the prosthetic group?
Answer & NCERT explanation
Correct answer: B — Catalase
Catalase contains haem as its prosthetic group, which gives it the ability to break down hydrogen peroxide into water and oxygen. The iron in the haem group is essential for catalase activity. Other enzymes listed have different prosthetic groups - succinate dehydrogenase has FAD, RuBisCO has no prosthetic group, carbonic anhydrase has zinc.
Read more NCERT concept on the PYQ
Prosthetic groups are organic compounds and are distinguished from other cofactors in that they are tightly bound to the apoenzyme. For example, in peroxidase and catalase, which catalyze the breakdown of hydrogen peroxide to water and oxygen, haem is the prosthetic group and it is a part of the active site of the enzyme.
NTA tests whether students know that prosthetic groups like haem are tightly bound to enzymes and form part of the active site. A common mistake is confusing prosthetic groups with cofactors—remember that prosthetic groups are permanently attached, while cofactors are loosely associated. In catalase and peroxidase, haem acts as the prosthetic group that directly participates in breaking down H₂O₂ into water and oxygen. To answer correctly, recall that prosthetic groups are organic, integral parts of the enzyme structure essential for catalytic activity, not just accessory molecules.
What does NCERT say about Prosthetic groups are organic?
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