The Cell Cycle and Mitosis
Think of the cell cycle as a three-stage journey that dividing cells must complete. First comes interphase, which is actually three phases rolled into one: G1 phase (cell growth and making more organelles), S phase (DNA replication), and G2 phase (more growth and protein synthesis). Then the cell moves through mitosis (nuclear division) and finally cytokinesis (splitting the cytoplasm).
Mitosis is absolutely crucial because it produces two daughter cells that are genetically identical to the parent cell. Before division begins, DNA replicates during S phase, creating sister chromatids joined at the centromere. This ensures each new cell gets an exact copy of the original DNA.
The beauty of mitosis lies in its precision - it's essential for growth (making you bigger), repair (healing injuries), and reproduction in some organisms. When this controlled process goes wrong due to mutations, it can lead to tumours or cancers.
Quick Tip: To calculate time spent in each phase, count cells in that stage, work out the percentage, then multiply by total cycle time!
