PROKARYOTIC CELLSEUKARYOTIC CELLS No nucleus. No membrane bound organelles. (ex. mitochondria, vacuole, chloroplast) A.) Cell division takes place in 2 steps: 1.) DNA is copied. 2.) Cell splits by binary fission. Contain a nucleus and organelles. Have a cell cycle. Repeating sequence of growth and division.
5 Stages G1 First growth phase S Synthesis phase G2 Second growth phase Mitosis Cell division Cytokinesis Division of cytoplasm
This is when the cell is preparing to divide. The LONGEST phase of the cell. cycle 90% of the cell’s life is spent in Interphase G1 – first growth phase: The cell doubles in size and the organelles double. S – synthesis phase: the DNA that makes up the chromatin is copied (DNA replication) this is the longest phase of interphase. G2 – second growth phase: Growth and preparation for mitosis.
Mitosis The nucleus of a cell is divided into two nuclei with the same number of chromosomes. Consists of 4 phases Prophase Metaphase Anaphase Telophase
Chromosome Single piece of coiled DNA. Replicated Chromosome A single piece of DNA that has been copied through DNA replication. Sister Chromatids 2 identical strands of DNA. Non-Replicated Chromosome Single strand of DNA before it is copied. Spindle Fibers Fibers that extend from the centrioles and help to pull apart chromosomes. Centrioles Organelles that aid in pulling apart replicated chromosomes. Centromere Structure that holds the replicated chromosomes together.
Longest phase of MITOSIS Chromatin coils and forms chromosomes Nuclear envelope breaks down Spindle fibers form and stretch from one end of the cell to the other They attach to the centrioles They help to pull the cell apart
Chromosomes line up in the middle of the cell.
Centromere of each chromosome splits. Two sister chromatids separate and move to opposite poles. Each chromatid becomes separate (non-replicated) chromosome in each daughter cell.
Last stage of Mitosis. Chromosomes at each pole uncoil and become chromatin. Nuclear envelope reforms. Spindle fibers break down.
NOT part of mitosis. The cytoplasm divides into two cells. Cell membrane reforms. In plant cells the cell wall reforms.
Video 1 Click the image to play the video segment. Video 1 Animal Cell Mitosis