What is the work of DNA polymerase?
The main function of DNA polymerase is to synthesize DNA from deoxyribonucleotides, the building blocks of DNA. The DNA copies are created by the pairing of nucleotides to bases present on each strand of the original DNA molecule.
What is the advantage of the proofreading function of DNA polymerase?
What is the advantage of the proofreading function of DNA polymerase? DNA polymerase can repair most mutations as they occur during DNA replication. Select the mitotic stage or interphase shown by the cell shown below. A cell with 10 chromosomes undergoes mitosis and cell division.
Does topoisomerase cut DNA?
In other words, DNA topoisomerase type I enzyme cleaves only one strand of DNA. To summarize, type II cleaves both strands of DNA, that results in a double-stranded break. Topoisomerases can either relieve negative supercoils, both positive and negative supercoils, or induce positive and negative supercoiling in DNA.
Is DNA gyrase the same as topoisomerase?
DNA gyrase, or simply gyrase, is an enzyme within the class of topoisomerase and is a subclass of Type II topoisomerases that reduces topological strain in an ATP dependent manner while double-stranded DNA is being unwound by elongating RNA-polymerase or by helicase in front of the progressing replication fork.
What is the role of topoisomerases?
Topoisomerase I is a ubiquitous enzyme whose function in vivo is to relieve the torsional strain in DNA, specifically to remove positive supercoils generated in front of the replication fork and to relieve negative supercoils occurring downstream of RNA polymerase during transcription.
What enzyme prevents Supercoiling?
What keeps DNA from Supercoiling?
Unwinding of the helix during DNA replication (by the action of helicase) results in supercoiling of the DNA ahead of the replication fork. If the supercoiling is not relieved, it will physically prevent the movement of helicase.
Why is negative supercoiling important?
Negative supercoiling has an important biological function of facilitating local- and global-strand separation of DNA molecules such as these occurring during transcription and replication, respectively (7–9). Strand separation relaxes the torsional stress in negatively supercoiled DNA (10).