Cell reproduction requires a cell to divide into 2 exact replicas. It has to re-organize its nucleus and cytoplasmic structure. Why do cells divide? • Replacement of worn out or injured cells (repairing wounds, replacing skin post sun burn peels, liver damage d/t alcohol) • Growth of the organism requires new cells • Reproduction Mitosis is the process by which the body makes new cells for replacement or growth. (Meiosis is the procedure for reproduction). In Mitosis, the cell will 1 st double its DNA, then divide into 2 new cells, resulting in a complete set of genes (chromosomes) passed on to the daughter cells (new cells). Mitosis is divided into 5 stages: (Students follow along on pg. 29-lab manual) 1. Interphase: In between cycles. DNA is copying. Chromosomes (which are a threadlike structure in the cell’s nucleus made of DNA) must be replicated. Before interphase you have 1 copy of each chromosome, after replication you have 2 chromatids held together by a centromere. The 2 chromatids are still
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