Prophase+230

White fish cell Onion root cell

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Prophase is the first stage, or phase, of cell mitosis, and occurs before metaphase. In this stage, chromosomes, which are made of fibers of chromatin, become visible within the nucleus. In the chromosomes there are two sister chromatids, which are joined by a centromere. The nucleus disappears and it stops producing ribosomes. Toward the end of prophase, a spindle of microtubules and other proteins form between two centrioles. Then the centrioles migrate to opposite ends of the cell. Finally, at the end of prophase the nuclear envelope disappears. The word "prophase" originated in the late 1800s, with "pro-" meaning before. So it literally means "before phase." =====


 By: Ryan Q, Cassidy P, Erin H, Lauren B