Question

What is the function of the DNA ligase?

• A. It catalyses the formation of phosphodiester bonds between two DNA fragments
• B. It catalyses hydrogen bond formation between two DNA strands
• C. It is used to synthesise complementary DNA strand on DNA template
• D. All of these

Answer 1

The correct option is A It catalyses the formation of phosphodiester bonds between two DNA fragments

DNA ligase is an enzyme which catalyses the formation of phosphodiester bonds between two nucleotides. It is used as a biotechnology tool to join two separate DNA molecules having blunt or sticky ends.


Hydrogen bonds are formed between two DNA strands if the two nitrogenous bases are complementary to each other. Adenine pairs with thymine and guanine pairs with cytosine.

DNA polymerase is involved in polymerisation of DNA by adding deoxyribonucleotides. Hence, it is used to synthesise complementary DNA strand on DNA template.