16.1 Cell Growth And Division How do plants and animals grow?

Cell Division and Growth We constantly produce new cells and old ones die out. This process helps us to grow and maintain health. Tissues that don’t go through cellular division are nerve cells and muscle cells.

Cell Cycle

Mitosis Mitosis is the process in which the nucleus divides into two identical nuclei. First, the nucleus of the cell divides, and then the cytoplasm divides. There are four stages in the process of Mitosis

1. Prophase Chromosomes have duplicated Two small structures called centrioles form (not in plants). Thread like fibers begin to stretch over the cell.

2. Metaphase Duplicated chromosomes line up in the center. Chromosomes are structures in the nucleus that contains hereditary material. Each centromere attaches to each spindle fiber.

3. Anaphase Each centromere divides into a chromatid. They separate and move to different ends.

4. Telophase Final stage Spindle fibers disappear. Nuclear membrane forms around the new nucleus. Cell plate forms in plants.

Results of Mitosis Division of the nucleus Produces two new nuclei that are identical to each other and the old nucleus. Each cell in your body except sex cells have 46 chromosomes.

Reproduction Reproduction is the process by which organisms produce others of the same kind. There are two types: Sexual and Asexual Asexual Reproduction Eukaryotes: Mitosis

Asexual Reproduction Fission – when a prokaryote divides to create two identical organisms. ex. Cutting a worm in half. Budding – when a new organism grows out from the parent. Regeneration – a new organism forms from part of another. ex. Starfish