Question

There are special proteins that help to open up DNA double helix in front of the replication fork. What is the name of the protein?
A. DNA ligase
B. DNA gyrase
C. DNA polymerase I
D. None of the above

Answer 1

Hint: In DNA replication, the two strands of DNA are separated with the help of special proteins. The parent strand forms a new complementary strand, making DNA semi conservative in nature.

Complete Answer:
Now, let us analyze each option to find the correct answer.
- Option A: DNA Ligase is a special protein that is used for attaching two strands of DNA in Biotechnological processes. It helps in joining two strands or two parts of DNA together, so, option A is incorrect.
- Option B: DNA Gyrase is a special protein that helps in opening or unwinding of the double helical structure of the DNA by reducing tension. So, option B is correct.
- Option C: DNA polymerase I helps to fill gaps that arise in DNA strands during DNA replication, repair and recombination. So, option C is incorrect.
- Option D: Since only one of the options satisfies for the answer of the question, hence, option D is incorrect.

So, the correct option is option B) DNA Gyrase.

Note: DNA replication is a semi conservative process. The new DNA consists of a parent strand and a new strand. In eukaryotic cells, the DNA replication takes place during the S phase of the interphase. The number of chromosomes are equal throughout.

Steps involved in DNA Replication:
1. Replication fork formation
2. Primer Building
3. Elongation
4. Termination