NEETBotanyBiomolecules (B)
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): In the enzyme peroxidase, haem is classified as a metal ion cofactor rather than a prosthetic group. Reason (R): Haem is an organic compound that is tightly bound to the apoenzyme, unlike metal ion cofactors which are inorganic. In the light of the above statements, choose the most appropriate answ
Options
- ABoth (A) and (R) are true and (R) is the correct explanation of (A)
- BBoth (A) and (R) are true but (R) is not the correct explanation of (A)
- C(A) is true but (R) is false
- D(A) is false but (R) is true
Correct answer
D. (A) is false but (R) is true
Step-by-step solution
Assertion (A) is false. According to NCERT, in enzymes like peroxidase and catalase, haem is classified as a prosthetic group, not a metal ion cofactor, even though it contains an iron atom. Reason (R) is true. Prosthetic groups are defined as organic compounds that are tightly bound to the apoenzyme. Haem fits this definition perfectly. In contrast, metal ion cofactors (like zinc in carboxypeptidase) are inorganic ions that form coordination bonds. Therefore, (A) is false but (R) is true. Answer: (A) is false but