Subtopic: Fundamentals of Biomolecules, enzyme kinetics
Question Statement:
In mismatch correction repair, the parental DNA strand is distinguished from the daughter strand by
(A) acetylation (B) phosphorylation (C) methylation (D) glycosylation
Options:
(A) acetylation
(B) phosphorylation
(C) methylation
(D) glycosylation
Official Answer Key:
C
Step-by-Step Solution & Explanation
### **Official Solution & Step-by-Step Derivation (GATE BT 2012 Q.1)**
**1. Governing Concept & Syllabus Classification**:
- **Section**: BT
- **Question Type**: **MCQ** (1 Mark)
- **Core Topic**: Quantitative & Analytical Aptitude
**2. Detailed Step-by-Step Analytical & Scientific Derivation**:
- **Systematic Conceptual & Option-by-Option Evaluation**:
- Problem Focus: *"In mismatch correction repair, the parental DNA strand is distinguished from the daughter strand by..."*
- **Option (C) [CORRECT]**: *"methylation"*
- Validated by canonical biochemistry/biotechnology literature. Specifically matches the molecular mechanism, kinetic model, or empirical finding required.
- **Option (A) [INCORRECT]**: *"acetylation"* does not satisfy the precise boundary conditions or molecular specificity.
- **Option (B) [INCORRECT]**: *"phosphorylation"* does not satisfy the precise boundary conditions or molecular specificity.
- **Option (D) [INCORRECT]**: *"glycosylation"* does not satisfy the precise boundary conditions or molecular specificity.
**3. Final Answer / Verification Summary**:
- **Official GATE Answer Key**: **C**
- **Scoring Criteria**: 1 Mark (Negative marking: -0.33 marks).
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