Section 3: Genetics, Cellular and Molecular Biology
Recombinant DNA technology
Subtopic: Fundamentals of Recombinant DNA technology
Question Statement:
Match the enzyme (Column I) with its corresponding function (Column II).
Column I Column II
P. Primase 1. RNA dependent RNA synthesis
Q. Reverse transcriptase 2. DNA dependent DNA synthesis
R. RNA Replicase 3. RNA dependent DNA synthesis
S. DNA Polymerase III 4. DNA dependent RNA synthesis
Options:
(A) P-4; Q-1; R-3; S-2
(B) P-2; Q-1; R-3; S-4
(C) P-3; Q-4; R-2; S-1
(D) P-4; Q-3; R-1; S-2
Official Answer Key:
D
Step-by-Step Solution & Explanation
### **Official Solution & Concept Analysis (GATE BT 2024 Q.38)**
**1. Governing Concept**:
- **Topic**: Molecular Biology & DNA/RNA Enzymology
- Enzymes and their catalytic functions:
- **P. Primase** $\rightarrow$ DNA-dependent RNA polymerase synthesizing short RNA primers for DNA replication $\rightarrow$ **4**
- **Q. Telomerase** $\rightarrow$ Specialized reverse transcriptase containing an intrinsic RNA template (**RNA-dependent DNA polymerase**) extending chromosome ends $\rightarrow$ **3**
- **R. Reverse Transcriptase** $\rightarrow$ Uses an RNA template to synthesize complementary cDNA (**RNA-dependent DNA polymerase**) $\rightarrow$ **1**
- **S. DNA Polymerase I** $\rightarrow$ Possesses $5' \rightarrow 3'$ exonuclease, $3' \rightarrow 5'$ proofreading, and DNA-dependent DNA synthesis activities $\rightarrow$ **2**
**2. Option Analysis**:
- **Option (A) is INCORRECT**: Misidentifies DNA Polymerase I function.
- **Option (B) is INCORRECT**: Primase is not an RNA-dependent polymerase.
- **Option (C) is INCORRECT**: Misassigns telomerase to primase.
- **Option (D) [P-4; Q-3; R-1; S-2] is CORRECT**: Perfectly matches all nucleic acid enzyme categories.
**3. Final Answer**:
- **Correct Choice**: **D**
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