Grade 10 science Nicole Klement 2011 Cell Division Mitosis Grade 10 science Nicole Klement 2011

Cells go through a cycle Most of their lives they are working at what ever job is their job: Ex: skin cells -protect, red blood cells- transport oxygen, nerve cells- transport signals etc There comes a point when they have to divide (usually when healing from trauma, when organism growth occurs, sometimes due to cancer) Division is a small portion of the cell cycle but we will be focussing on it in this particular lesson

Diagram of the cell cycle

Mitosis Mitosis is the process of cell division which produces two daughter cells from a single parent cell. The daughter cells are identical to one another and to the original parent cell.

MEMORIZE THIS MNEUMONIC!~~ Phases of Mitosis Interphase Prophase Metaphase Anaphase Telophase I P M A T MEMORIZE THIS MNEUMONIC!~~

Interphase The cell prepares for mitosis Chromosomes duplicate in the nucleus

Prophase Chromosomes shorten and thicken Membrane around the nucleus disappears The chromatin, diffuse in interphase, condenses into chromosomes. Each chromosome has duplicated and now consists of two sister chromatids.  

Metaphase Duplicated/ paired chromosomes line up in the middle of the nucleus

Anaphase Spindle fibres pull duplicated/paired chromosomes apart to the opposite end of the cell

Telophase Cell begins to pinch in two New nuclear membrane starts to form Cytokinesis -division of the cytoplasm into equal parts

Conclusion Each new cell ends up with the same amount of genetic material as the original cell. Both daughter cells are identical to the parent cells.

Discussion Question How many chromosomes would you expect to find in each daughter cell after mitosis? Predict what might happen to each daughter cell if all the chromosomes moved to only one side of the cell during anaphase. Why is it necessary to duplicate the nuclear material?

Diseases caused by faulty cell division (Mitosis or Meiosis) 1. Cancer Ex: The rate of cell division is usually strictly controlled. The division and thus growth of cancer cells is not controlled. They just go on dividing and growing, out of control. 2. Genetically based diseases & Syndromes Ex: Down Syndrome

Your Chromosomes A photograph showing the number, shapes and sizes of chromosomes in a cell. All pairs of chromosomes are homologus (identical in size and shape) except the sex chromosomes (23rd pair) One chromosome comes from the father (paternal) one chromosome comes from the mother (maternal

Down Syndrome Chromosomes (kariotype) Karyotype photograph of the entire set of chromosomes. 23 pairs for a total of 46 In Down Syndrome-trisomic for chromosome 21, carries an extra chromosome

Cancer Overactive mitosis (too much cell division too fast) can lead to the formation of a tumor – called neoplasia or “cancer”. The cells in our body need to reproduce through division, but when cell division gets out of control it starts causing problems . 16

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