Interphase is a crucial phase of the cell cycle that occurs before cell division (mitosis or meiosis) and is typically divided into three sub-phases: G1 (Gap 1), S (Synthesis), and G2 (Gap 2). During interphase, the cell undergoes various activities essential for growth, preparation for division, and overall maintenance. Here's a breakdown of what happens in each sub-phase:
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G1 Phase (Gap 1):
- Cell Growth: The cell increases in size and synthesizes proteins and organelles.
- Metabolism: Cellular metabolism is active, with the cell carrying out its normal functions.
- Response to Environmental Signals: The cell monitors environmental conditions and may receive signals to divide.
- Preparation for DNA Replication: The cell begins to prepare the necessary components for DNA replication.
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S Phase (Synthesis):
- DNA Replication: The cell replicates its DNA, resulting in two complete sets of chromosomes, each consisting of sister chromatids.
- Centrosome Duplication: The centrosome, an organelle that helps organize microtubules during cell division, is also duplicated.
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G2 Phase (Gap 2):
- Further Growth: The cell continues to grow and produce proteins necessary for mitosis.
- DNA Repair: The cell checks and repairs any errors in DNA replication to ensure genetic integrity.
- Preparation for Mitosis: The cell begins to reorganize its contents in preparation for the upcoming mitotic phase.
Throughout interphase, the cell is active in carrying out its functions, and it is during this time that it prepares for division. Interphase can take a significant amount of time compared to the actual division process, and it accounts for the majority of the cell cycle.