Interphase is the phase of the cell cycle that occurs before cell division, encompassing three distinct stages: G1 (Gap 1), S (Synthesis), and G2 (Gap 2). During interphase, the cell prepares for division and engages in various metabolic processes. Here’s a breakdown of what happens in each stage:
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G1 Phase (Gap 1):
- The cell grows in size and synthesizes various organelles and proteins.
- Metabolic activities increase as the cell carries out normal functions.
- The cell accumulates the necessary resources and energy required for DNA replication.
- At the end of G1, the cell checks its internal and external environment and can enter the G0 phase if conditions are not favorable for division.
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S Phase (Synthesis):
- DNA replication occurs, resulting in the duplication of each chromosome.
- Each chromosome, after replication, consists of two sister chromatids held together at the centromere.
- The cell also continues to synthesize proteins necessary for chromosome segregation during mitosis.
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G2 Phase (Gap 2):
- The cell continues to grow and produces proteins and organelles needed for mitosis.
- The cell undergoes a final check to ensure that DNA has been accurately replicated and any damage is repaired.
- The cell prepares for mitosis by producing the necessary structures, such as microtubules for spindle formation.
Overall, interphase is crucial for ensuring that the cell is fully prepared to divide, and it serves as a significant period of growth and preparation, rather than mere inactivity. It typically accounts for the majority of the cell cycle, often lasting hours to days.