Choose the correct answer from the options given below
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To remember cofactors easily, associate Manganese directly with water-splitting (OEC) in photosynthesis, Molybdenum with nitrogen fixation (diazotrophy), Copper with terminal oxidases, and Zinc with auxin (IAA) production.
Step 1: Understanding the Concept:
This question requires matching specific biochemical and physiological processes in plants with their corresponding essential inorganic micronutrient activators or cofactors. Step 2: Detailed Explanation:
Let us analyze each pair systematically:
(A). Photolysis of water: During the light reactions of photosynthesis, the split of water molecules to release oxygen, protons, and electrons occurs in Photosystem II. This reaction is catalyzed by the oxygen-evolving complex (OEC), which requires Manganese (\(Mn^{2+}\)) and Chlorine (\(Cl^-\)) ions as essential cofactors. Thus, (A) matches with (III).
(B). Diazotrophy: Diazotrophy refers to the process of biological nitrogen fixation performed by diazotrophs. The key enzyme, nitrogenase, contains iron-molybdenum (Fe-Mo) cofactors at its catalytic center. Molybdenum is critical for its operation. Thus, (B) matches with (IV).
(C). Cytochrome oxidase: This is the terminal enzyme of the mitochondrial electron transport chain. It contains iron (heme groups) and copper (\(Cu\)) centers that are crucial for transferring electrons to molecular oxygen. Thus, (C) matches with (II).
(D). Biosynthesis of IAA: Indole-3-acetic acid (IAA) is the primary natural auxin in plants. Zinc (\(Zn\)) is required as an activator for the enzyme tryptophan synthase, which catalyzes the synthesis of tryptophan—the direct chemical precursor for IAA biosynthesis. Thus, (D) matches with (I).
This gives the combination: (A) - (III), (B) - (IV), (C) - (II), (D) - (I). Step 2: Final Answer:
The correct option is (B).
