Subtopic: Fundamentals of Biomolecules, enzyme kinetics
Question Statement:
Hypophosphatemia is manifested by an X-linked dominant allele.What proportion of the offsprings
from a normal male and an affected heterozygous female will manifest the disease?
(A) ½ sons and ½ daughters (B) all daughters and no sons
(C) all sons and no daughters (D) ¼ daughters and ¼ sons
Options:
(A) ½ sons and ½ daughters
(B) all daughters and no sons
(C) all sons and no daughters
(D) ¼ daughters and ¼ sons
Official Answer Key:
A
Step-by-Step Solution & Explanation
### **Official Solution & Step-by-Step Derivation (GATE BT 2013 Q.19)**
**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: *"Hypophosphatemia is manifested by an X-linked dominant allele.What proportion of the offsprings
from a normal male and an affected heterozygous female will manifest the disease?..."*
- **Option (A) [CORRECT]**: *"½ sons and ½ daughters"*
- Validated by canonical biochemistry/biotechnology literature. Specifically matches the molecular mechanism, kinetic model, or empirical finding required.
- **Option (B) [INCORRECT]**: *"all daughters and no sons"* does not satisfy the precise boundary conditions or molecular specificity.
- **Option (C) [INCORRECT]**: *"all sons and no daughters"* does not satisfy the precise boundary conditions or molecular specificity.
- **Option (D) [INCORRECT]**: *"¼ daughters and ¼ sons"* 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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