The product of complete digestion of the plasmid shown below with EcoRI and HaeIII was
purified and used as a template in a reaction containing Klenow fragment of DNA
polymerase, dNTPs and [-32P]-dATP in a suitable reaction buffer. The product thus
obtained was purified and subjected to gel electrophoresis followed by autoradiography.
The number of bands that will appear on the X-ray film is _________
EcoRI
HaeIII
HaeIII
5 kb
3 kb
1 kb
EcoRI
HaeIII
5’-GAATTC-3’
3’-CTTAAG-5’
5’-GGCC-3’
3’-CCGG-5’
GATE 2018 Biotechnology
Official Answer Key:
2 to
Step-by-Step Solution & Explanation
### **Official Solution & Step-by-Step Derivation (GATE BT 2018 Q.64)**
**1. Governing Concept & Syllabus Classification**:
- **Section**: BT
- **Question Type**: **NAT** (22 Marks)
- **Core Topic**: Biochemistry, Microbiology & Molecular Biology
**2. Detailed Step-by-Step Analytical & Scientific Derivation**:
- **Mathematical & Quantitative Formulation**:
- Problem Statement: *"The product of complete digestion of the plasmid shown below with EcoRI and HaeIII was
purified and used as a template in a reaction containing Klenow fragment of DNA
polymerase, dNTPs and [-32P]-dATP in a suitable rea..."*
- 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**: **2 to**.
**3. Final Answer / Verification Summary**:
- **Official GATE Answer Key**: **2 to**
- **Scoring Criteria**: 22 Marks (Negative marking: -0.0 marks).
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