Question

What enzyme unzips DNA and breaks the hydrogen bond?

Answer 1

Hint: DNA is a double-stranded helix in which the two strands are joined together by the hydrogen bond. The first step in DNA replication is breaking the hydrogen bond so that the copy of each strand can be made. DNA replication is an important step of cell division.

Complete answer:
DNA is the genetic material contained in the nucleus of the eukaryotic cell. The first step of cell division is the replication of DNA.

To answer this question, we must know the structure and replication of DNA. The DNA is a double helix. Each stand contains complementary bases. The complementary bases are joined by the hydrogen bond.

The DNA replication takes place by the following steps-
1. The unzipping of the double helix and separation of the two strands- In this process, the two strands of the DNA uncoil and then the hydrogen bond between the strands. The Y shaped DNA strand is formed due to the unzipping of the DNA. This process takes place with the help of an enzyme called helicase. The two strands separate and act as a template for synthesising new strands.

2. The priming of the template- A short segment of the RNA acts as a primer that helps in the elongation of the strand. The DNA polymerase starts adding nucleotide from 5’ to 3’ end.
3. Assembly of the new segment- The proofreading activity is performed by the exonuclease and the two strands are joined by the ligase.

Thus, the correct answer is helicase.

Note: DNA replication is a process in which there are several check gates that help in proofreading and ensure error-free replication. DNA replication is important for the growth, development and repair of the organism. It is also an important part of the inheritance.