The amino acid sequence of a peptide is Phe-Leu-Ile-Met-Ser-Leu. The number of codons that encode the amino acids present in this peptide is given below:
Phe: 2 codons; Leu: 6 codons; Ile: 3 codons; Met: 1 codon; Ser: 4 codons.
The number of unique DNA sequences that can encode this peptide is ________.
Official Answer Key:
864 to 864
Step-by-Step Solution & Explanation
### **Official Solution & Step-by-Step Derivation (GATE BT 2020 Q.57)**
**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 amino acid sequence of a peptide is Phe-Leu-Ile-Met-Ser-Leu. The number of codons that encode the amino acids present in this peptide is given below:
Phe: 2 codons; Leu: 6 codons; Ile: 3 codons; Met: 1 codon; Ser: 4 ..."*
- 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**: **864 to 864**.
**3. Final Answer / Verification Summary**:
- **Official GATE Answer Key**: **864 to 864**
- **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.