Mitosis is a crucial process for cell division, allowing one cell to divide and produce two identical daughter cells. The stages of mitosis are prophase, metaphase, anaphase, and telophase, each with distinct characteristics.
Prophase: In this first stage, the chromatin condenses into tightly coiled chromosomes, becoming visible under a microscope. Each chromosome is made up of two sister chromatids held together at the centromere. The nucleolus disappears, and the spindle apparatus begins to form, with spindle fibers extending from the centrosomes, which move to opposite poles of the cell. The cell begins to take on an oval shape as it prepares for division.
Metaphase: During metaphase, the chromosomes align at the cell’s equatorial plane, known as the metaphase plate. The spindle fibers attach to the centromeres of the chromosomes. This alignment is crucial for ensuring that each daughter cell will receive an identical set of chromosomes. At this point, the cell appears oval, with visibly lined-up chromosomes in the middle.
Anaphase: Anaphase is marked by the separation of sister chromatids as the spindle fibers shorten, pulling them towards opposite poles of the cell. The cell elongates during this phase, beginning to take on a more elongated shape as the chromatids move away from each other. This ensures that each new daughter cell will contain the same genetic material.
Telophase: In the final stage, telophase, the chromatids reach the poles and begin to de-condense back into less visible chromatin. Nuclear membranes start to form around each set of chromosomes, leading to the re-establishment of two distinct nuclei within the cell. The spindle apparatus disassembles, and the cell continues to elongate as it prepares for cytokinesis, which is the final separation into two daughter cells. The process leaves the cell looking nearly split in two, with two well-defined nuclei appearing.
Overall, mitosis ensures the accurate distribution of genetic material during cell division, and each stage plays a crucial role in the successful completion of this process.