What is the role of DNA ligase in making recombinant DNA?
Answer and explanation
Correct answer: A. It joins the sugar-phosphate backbones of the cut plasmid and the inserted gene
- Step 1: After the gene and plasmid are cut with the same restriction enzyme, the sticky ends pair by hydrogen bonds.
- Step 2: DNA ligase then forms phosphodiester bonds to seal the backbone.
Answer
It joins the sugar-phosphate backbones of the cut plasmid and the inserted gene.
Why not the others: It cuts the DNA at specific recognition sequences: describes restriction enzymes. It separates the two strands before copying: describes DNA helicase. It adds complementary nucleotides to a primer: describes DNA polymerase.
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