10% of the population in a town is HIV+. A new diagnostic kit for HIV detection is available; this
kit correctly identifies HIV+ individuals 95% of the time, and HIV− individuals 89% of the time. A
particular patient is tested using this kit and is found to be positive. The probability that the
individual is actually positive is _______
Options:
(A) inside the barrel
(B) at the amino side of the strands
(C) at the carboxy side of the strands
(D) at any arbitrary site
Official Answer Key:
C
Step-by-Step Solution & Explanation
### **Official Solution & Step-by-Step Derivation (GATE BT 2014 Q.65)**
**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: *"The active site in the alpha/beta barrel structures is usually located..."*
- **Option (C) [CORRECT]**: *"at the carboxy side of the strands"*
- Validated by canonical biochemistry/biotechnology literature. Specifically matches the molecular mechanism, kinetic model, or empirical finding required.
- **Option (A) [INCORRECT]**: *"inside the barrel"* does not satisfy the precise boundary conditions or molecular specificity.
- **Option (B) [INCORRECT]**: *"at the amino side of the strands"* does not satisfy the precise boundary conditions or molecular specificity.
- **Option (D) [INCORRECT]**: *"at any arbitrary site
END OF THE QUESTION PAPER
BT
9/9
BT ("* 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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