Biomolecules, enzyme kinetics

### **Step-by-Step Solution & Mathematical Derivation (GATE BT 2013 Q.24)** **1. Governing Concept & Definition**: - **Topic**: Bioinformatics & Sequence Alignment Percentage Identity - Percentage sequence identity is defined as: $\% \text{Identity} = \frac{\text{Number of Identical Positions}}{\text{Length of Alignment (including gaps)}} \times 100\%$ **2. Detailed Step-by-Step Calculation**: - **Given Alignment**: - Alignment length $= 6$ positions (or matching length) - Identical matching residues $= 4$ out of $6$: $\% \text{Identity} = \frac{4}{6} \times 100\% = \frac{2}{3} \times 100\% \approx 66.67\%$ **3. Final Answer**: - **Calculated Value**: **66.7%** - **Official GATE Accepted Range**: **66.5 to 66.7**