Question:medium

Which enzyme acts as “molecular glue” to join DNA fragments?

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DNA ligase is essential in DNA replication (joining Okazaki fragments) and in genetic engineering for creating recombinant DNA molecules.
Updated On: Apr 22, 2026
  • DNA Polymerase
  • DNA Ligase
  • Helicase
  • Restriction Endonuclease
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The Correct Option is B

Solution and Explanation

Step 1: Understanding the Question:
The question identifies a specific enzyme based on its functional nickname in molecular biology and genetic engineering.
Step 2: Detailed Explanation:
In DNA replication and biotechnology, fragments of DNA need to be linked together covalently.
DNA Ligase facilitates the joining of DNA strands together by catalyzing the formation of a phosphodiester bond.
- It seals the "nicks" between Okazaki fragments on the lagging strand during replication.
- In recombinant DNA technology, it "glues" the gene of interest into a vector (like a plasmid).
In contrast:
- Helicase "unzips" DNA.
- Restriction Endonuclease "cuts" DNA (molecular scissors).
- DNA Polymerase "synthesizes" new strands.
Step 3: Final Answer:
The "molecular glue" is DNA Ligase.
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