Search results
Results from the WOW.Com Content Network
During S-phase, the cell converts pre-RCs into active replication forks to initiate DNA replication. [4] This process depends on the kinase activity of Cdc7 and various S-phase CDKs, both of which are upregulated upon S-phase entry. [4] Activation of the pre-RC is a closely regulated and highly sequential process.
File:DNA_replication_en.svg licensed with PD-user 2009-06-01T14:09:19Z Bibi Saint-Pol 691x336 (113021 Bytes) {{Information |Description= {{en|DNA replication or DNA synthesis is the process of copying a double-stranded DNA molecule. This process is paramount to all life as we know it.}} |Source=Own work |Date= 2007-01-24 |Author= [
The eukaryotic cell cycle consists of four distinct phases: G 1 phase, S phase (synthesis), G 2 phase (collectively known as interphase) and M phase (mitosis and cytokinesis). M phase is itself composed of two tightly coupled processes: mitosis, in which the cell's nucleus divides, and cytokinesis, in which the cell's cytoplasm and cell membrane divides forming two daughter cells.
Mitosis is preceded by the S phase of interphase (during which DNA replication occurs) and is followed by telophase and cytokinesis, which divide the cytoplasm, organelles, and cell membrane of one cell into two new cells containing roughly equal shares of these cellular components. [2]
The process of duplicating DNA is called DNA replication, and it takes place by first unwinding the duplex DNA molecule, starting at many locations called DNA replication origins, followed by an unzipping process that unwinds the DNA as it is being copied. However, replication does not start at all the different origins at once.
Within eukaryotes, DNA replication is controlled within the context of the cell cycle. As the cell grows and divides, it progresses through stages in the cell cycle; DNA replication takes place during the S phase (synthesis phase). The progress of the eukaryotic cell through the cycle is controlled by cell cycle checkpoints.
S-phase: During cell replication when DNA is replicated, and is initiated by the S-phase-promoting factor(SPF) cyclin complexes. [2] The DNA replication takes place, due to the increase in SPF during the switching from G1 to S phase in the cell cycle. [2] SPF is also used to inhibit double replication of chromosomes in the cell cycle, which is ...
At the same time, during S phase all cells must duplicate their DNA very precisely, a process termed DNA replication. Once DNA replication has finished, in eukaryotes the DNA molecule is compacted and condensed, to form the mitotic chromosomes, each one constituted by two sister chromatids, which stay held together by the establishment of ...