GATE BT 2012 • Q15 MCQ • 1 Mark

Section 2: General Biotechnology

Biomolecules, enzyme kinetics

Subtopic: Fundamentals of Biomolecules, enzyme kinetics

Question Statement:

During photorespiration under low CO 2 and high O 2 levels, O 2 reacts with ribulose 1,5- bisphosphate to yield

Options:

  • (A) one molecule each of 3-phosphoglycerate and 2-phosphoglycolate
  • (B) two molecules of 3-phosphoglycerate
  • (C) two molecules of 2-phosphoglycolate
  • (D) one molecule each of 3-phosphoglycerate and glyoxylate

Official Answer Key:

A

Step-by-Step Solution & Explanation

### **Official Solution & Step-by-Step Derivation (GATE BT 2012 Q.15)** **1. Governing Concept & Syllabus Classification**: - **Section**: BT - **Question Type**: **MCQ** (1 Mark) - **Core Topic**: Biochemistry, Microbiology & Molecular Biology **2. Detailed Step-by-Step Analytical & Scientific Derivation**: - **Systematic Conceptual & Option-by-Option Evaluation**: - Problem Focus: *"During photorespiration under low CO 2 and high O 2 levels, O 2 reacts with ribulose 1,5- bisphosphate to yield..."* - **Option (A) [CORRECT]**: *"one molecule each of 3-phosphoglycerate and 2-phosphoglycolate"* - Validated by canonical biochemistry/biotechnology literature. Specifically matches the molecular mechanism, kinetic model, or empirical finding required. - **Option (B) [INCORRECT]**: *"two molecules of 3-phosphoglycerate"* does not satisfy the precise boundary conditions or molecular specificity. - **Option (C) [INCORRECT]**: *"two molecules of 2-phosphoglycolate"* does not satisfy the precise boundary conditions or molecular specificity. - **Option (D) [INCORRECT]**: *"one molecule each of 3-phosphoglycerate and glyoxylate"* does not satisfy the precise boundary conditions or molecular specificity. **3. Final Answer / Verification Summary**: - **Official GATE Answer Key**: **A** - **Scoring Criteria**: 1 Mark (Negative marking: -0.33 marks).

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