Subtopic: Fundamentals of Biomolecules, enzyme kinetics
Question Statement:
E. coli was grown in '5N medium for several generations. Cells were then transferred
to '4N medium, allowed to grow for 4 generations and DNA was isolated
immediately. The proportion of total DNA with intermediate density is
(round off to 2 decimal places).
Official Answer Key:
0.11 to 0.14
Step-by-Step Solution & Explanation
### **Official Solution & Step-by-Step Derivation (GATE BT 2020 Q.54)**
**1. Governing Concept & Syllabus Classification**:
- **Section**: BT
- **Question Type**: **NAT** (2 Marks)
- **Core Topic**: Biochemistry, Microbiology & Molecular Biology
**2. Detailed Step-by-Step Analytical & Scientific Derivation**:
- **Mathematical & Quantitative Formulation**:
- Problem Statement: *"E. coli was grown in '5N medium for several generations. Cells were then transferred
to '4N medium, allowed to grow for 4 generations and DNA was isolated
immediately. The proportion of total DNA with intermediate densit..."*
- Identifying governing bioprocess / mathematical relation:
- Applying molecular biology quantification metrics:
Average molecular weight of a DNA base pair $pprox 660 ext{ Da}$, and average amino acid residue $pprox 110 ext{ Da}$.
$\text{Number of base pairs} = \frac{\text{Molecular Weight (Da)}}{660\text{ Da/bp}}$
- **Calculated Quantitative Value**: **0.11 to 0.14**.
**3. Final Answer / Verification Summary**:
- **Official GATE Answer Key**: **0.11 to 0.14**
- **Scoring Criteria**: 2 Marks (Negative marking: -0.0 marks).
Practice This in Real CBT Exam Interface
Test yourself with the official TCS-iON palette, virtual calculator, and immediate performance analytics.