Section 4: Bioprocess Engineering and Process Biotechnology
Mass transfer in bioprocesses (kLa)
Subtopic: Fundamentals of Mass transfer in bioprocesses (kLa)
Question Statement:
The possible number of Sall restriction sites in a 9 kb double-stranded DNA,
with all four bases occurring in equal proportion (rounded off to the nearest
integer)
is
Official Answer Key:
2
Step-by-Step Solution & Explanation
### **Official Solution & Step-by-Step Derivation (GATE BT 2021 Q.64)**
**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: *"The possible number of Sall restriction sites in a 9 kb double-stranded DNA,
with all four bases occurring in equal proportion (rounded off to the nearest
integer)
is..."*
- 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 $pprox 110 ext{ Da}$.
$\text{Number of base pairs} = \frac{\text{Molecular Weight (Da)}}{660\text{ Da/bp}}$
- **Official Answer Key Interval**: Evaluated numerical range is **2.0 to 2.0** (Target value: **2.0 to 2.0**).
**3. Final Answer / Verification Summary**:
- **Official GATE Answer Key**: **2.0 to 2.0**
- **Scoring Criteria**: 2 Marks (Negative marking: -0.0 marks).
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