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PEP (phosphoenol pyruvate) group translocation, also known as the phosphotransferase system or PTS, is a distinct method used by bacteria for sugar uptake where the source of energy is from phosphoenolpyruvate (PEP). It is known to be a multicomponent system that always involves enzymes of the plasma membrane and those in the cytoplasm.
Cells with a defective G 2-M checkpoint will undergo apoptosis or death after cell division if they enter the M phase before repairing their DNA. [1] The defining biochemical feature of this checkpoint is the activation of M-phase cyclin-CDK complexes, which phosphorylate proteins that promote spindle assembly and bring the cell to metaphase. [2]
This protein functions as a regulator at the early steps of DNA replication. It localizes in the cell nucleus during cell cycle phase G1, but translocates to the cytoplasm at the start of S phase. The subcellular translocation of this protein during the cell cycle is regulated through its phosphorylation by cyclin-dependent kinases .
The cell cycle is a series of complex, ordered, sequential events that control how a single cell divides into two cells, and involves several different phases. The phases include the G1 and G2 phases, DNA replication or S phase, and the actual process of cell division, mitosis or M phase. [1]
[5] [6] After growth from the zygote to the adult, cell division by mitosis allows for continual construction and repair of the organism. [7] The human body experiences about 10 quadrillion cell divisions in a lifetime. [8] The primary concern of cell division is the maintenance of the original cell's genome.
S phase (Synthesis phase) is the phase of the cell cycle in which DNA is replicated, occurring between G 1 phase and G 2 phase. [1] Since accurate duplication of the genome is critical to successful cell division, the processes that occur during S-phase are tightly regulated and widely conserved.
Figure 1: Schematic of the cell cycle. outer ring: I = Interphase, M = Mitosis; inner ring: M = Mitosis, G 1 = Gap 1, G 2 = Gap 2, S = Synthesis; not in ring: G 0 = Gap 0/Resting. Replication timing refers to the order in which segments of DNA along the length of a chromosome are duplicated.
[1] [2] It stimulates the mitotic and meiotic phases of the cell cycle. MPF promotes the entrance into mitosis (the M phase) from the G 2 phase by phosphorylating multiple proteins needed during mitosis. MPF is activated at the end of G 2 by a phosphatase, which removes an inhibitory phosphate group added earlier.