Subtopic: Fundamentals of Biomolecules, enzyme kinetics
Question Statement:
Determine the correctness or otherwise of the following Assertion (a) and the Reason (T).
Assertion : N-methyl-N'-nitro-N-nitrosoguanidine (NTG) is an effective chemical
mutagen.
Reason : Mutations induced by NTG mainly are the GC → AT transitions.
Options:
(A) both (a) and (r) are true and (r) is
(B) both (a) and (r) are true but (r) is not the
the correct reason for (a)
correct reason for (a)
(C) (a) is true but (r) is false
(D) (a) is false but (r) is true
Official Answer Key:
C
Step-by-Step Solution & Explanation
### **Official Solution & Step-by-Step Derivation (GATE BT 2011 Q.31)**
**1. Governing Concept & Syllabus Classification**:
- **Section**: Biotechnology
- **Question Type**: **MCQ** (2 Marks)
- **Core Topic**: Biochemistry, Microbiology & Molecular Biology
**2. Detailed Step-by-Step Analytical & Scientific Derivation**:
- **Systematic Conceptual & Option-by-Option Evaluation**:
- Problem Focus: *"Determine the correctness or otherwise of the following Assertion (a) and the Reason (T).
Assertion : N-methyl-N'-nitro-N-nitrosoguanidine (NTG) is an effective chemical
mutagen.
Reason : Mutations induced by NTG mainly ..."*
- **Option (C) [CORRECT]**: *"(a) is true but (r) is false"*
- Validated by canonical biochemistry/biotechnology literature. Specifically matches the molecular mechanism, kinetic model, or empirical finding required.
- **Option (A) [INCORRECT]**: *"both (a) and (r) are true and (r) is"* does not satisfy the precise boundary conditions or molecular specificity.
- **Option (B) [INCORRECT]**: *"both (a) and (r) are true but (r) is not the
the correct reason for (a)
cor"* does not satisfy the precise boundary conditions or molecular specificity.
- **Option (D) [INCORRECT]**: *"(a) is false but (r) is true"* does not satisfy the precise boundary conditions or molecular specificity.
**3. Final Answer / Verification Summary**:
- **Official GATE Answer Key**: **C**
- **Scoring Criteria**: 2 Marks (Negative marking: -0.66 marks).
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