Cell growth briefly at M phase when the nucleus and then the cell divide in two. The process of cell division, called cell cycle, has four major parts called phases. The first part, called G phase is marked by synthesis of various enzymes that are required for DNA replication. The second part of the cell cycle is the S phase, where DNA replication produces two identical sets of chromosomes. The third part is the G phase in which a significant protein synthesis occurs, mainly involving the production of microtubules that are required during the process of division, called mitosis. The fourth phase,
Pfu DNA polymerase Pfu DNA polymerase "Pfu" DNA polymerase is an enzyme found in the hyperthermophilic archaeon "Pyrococcus furiosus", where it functions to copy the organism's DNA during cell division. In the laboratory setting, "Pfu" is used to amplify DNA in the polymerase chain reaction (PCR), where the enzyme serves the central function of copying a new strand of DNA during each extension step. "Pfu" DNA polymerase has superior thermostability and proofreading properties compared to "Taq" DNA polymerase. Unlike "Taq" DNA polymerase, "Pfu" DNA polymerase possesses 3' to 5' exonuclease proofreading activity, meaning that as the DNA is assembled from the 5' end