Question

DNA ligase is an enzyme that catalyses the

• A. Splitting of DNA threads into small bits
• B. Joining of the fragments of DNA
• C. Denaturation of DNA
• D. Synthesis of DNA

Answer 1

The correct option is B Joining of the fragments of DNA

Restriction endonucleases recognize specific sequences within DNA and cut to it into small fragments. The specific sites are 4-6 bp long and are called as restriction sites. Each restriction endonuclease has a specific restriction site. Ligase enzyme joins two large molecules by forming a new chemical bond; for example, DNA ligase joins two DNA fragments together via phosphodiester bond between two nucleotides. Synthesis of DNA is carried out through DNA replication in which DNA polymerase enzyme add the deoxyribonucleotides to a primer in 5' to 3' direction. Here, parental strand serves as template. Denaturation of DNA is separation of the two parent strands which is accomplished by helicases. These enzymes unwind the DNA bidirectionally and create two potential replication forks. Correct answer is B.