G1 Phase
The G1 phase (Gap 1 phase) or post-mitotic phase is a period in the cell cycle during interphase, before the S phase. For many cells, this phase is the major period of cell growth during its lifespan. During this stage new organelles are being synthesized, so the cell requires both structural proteins and enzymes, resulting in a great amount of protein synthesis and a high rate of metabolism in the cell.
These subphases may be affected by limiting growth factors, nutrient supply, temperature, and additional inhibiting factors. A rapidly dividing human cell which divides every 24 hours spends 9 hours in G1 phase.
A cell may pause in the G1 phase before entering the S phase and enter a state of dormancy called the G0 phase. Most mammalian cells do this. In order to divide, the cell re-enters the cycle in S phase.
Read more about G1 Phase: Status of The Genome, Restriction Point
Famous quotes containing the word phase:
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—Susan Ferraro (20th century)