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Sam’s Puppy. Body cell reproduction involves producing new daughter cells for growth of tissues as well as repair and replacement of old cells.

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Sam’s Puppy

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Sam’s Puppy

  • Body cell reproduction involves producing new daughter cells for growth of tissues as well as repair and replacement of old cells.

  • Most living body cells eventually divide into two cells through a process called mitosis. This can happen because food and nutrients are broken down and become building blocks for new living materials like the new cells produced during cell division.


LT #5 I can Describe howcells multiply.


Why do cells divide?

  • Weeds can grow pretty fast. In fact, the stems and roots of a fast-growing plant seem to get longer over night. Where do the new stem and root parts come from?

    • They are made when existing cells divide to form new cells. This process is called cell division.


Why do cells divide?

  • Eventually cells need to duplicate. There are two types of cell division, mitosis (growth) and meiosis (reproduction).

  • Mitosis allows organisms to grow larger, and also helps organisms replace injured cells. GROWTH!


Mitosis

  • The big idea to remember is that mitosis is the simple duplication of a cell and all of its parts.

  • It duplicates its DNA and the two new cells (daughter cells: cells resulting from the replication and division of a single parent cell) have the same pieces and genetic code.


Two identical copies come from one original. Start with one; get two that are the same. Get the idea?


Mitosis

  • Before a eukaryotic cell (a cell with an organized nucleus) divides, the genetic material in the nucleus of the cell copies itself.

  • When the cell divides, the nuclear material splits in half so that each daughter cellgets genetic material that is the same as that of the parent cell.


Mitosis

  • The dividing of the nuclear material is known as mitosis.

  • In the last stage of cell division, the cytoplasm divides as well.

  • There are now two complete cells where there used to be one.


Science Alert!

  • The terms mitosis and cell division are sometimes used interchangeably.

  • BUT…mitosis really refers only to the dividing of the nuclear material.

  • While…cell divisionis the complete process of copying and dividing the whole cell.


Cell Division Phases

  • Beyond the idea that two identical cells are created, there are predictable stages or phases in the cell division process.

  • These steps ensure that the new daughter cells are the same as the cell from which they formed.


Cell Division

  • There are 5 basic phases in the life-cycle of a cell.

    • Interphase

    • Prophase

    • Metaphase

    • Anaphase

    • Telophase


Cell Division

  • The following mnemonic devices can help you remember the phases of cell division.

    • I prefer milk and tea.

    • I propose meeting at ten.

    • In Poland men are tall.

  • CAN YOU COME UP WITH YOUR OWN mnemonic device?


  • Cell Division/Mitosis

    • Interphase

      • The stage before cell division starts.

      • As a cell prepares to divide, each chromosome in the nucleus makes an exact copy of itself.

      • Chromosomes: a structure made of DNA that contains the genetic info used to direct cell activity and make new cells


    Cell Division/Mitosis

    • Prophase

      • The nucleus prepares for cell division.

      • The genetic material shortens and thickens.

      • The chromosome copies are held together at their centers, so they form a sort of “X.”


    Cell Division/Mitosis

    • Metaphase

      • The two copies of each chromosome line up in the center of the cell.


    Cell Division/Mitosis

    • Anaphase

      • The copies separate.

      • One complete set of chromosomes is pulled to one side of the cell.

      • The other complete set is pulled to the other side of the cell.


    Cell Division

    • Telophase

      • Final stage of cell division

      • The cytoplasm pinches in at the center of the cell, dividing the cell in half.

      • When cell division is complete, two new daughter cells are formed.

      • The daughter cells are identical to the parent cell.


    Two identical copies come from one original. Start with one; get two that are the same. Get the idea?


    Mitosis Rap Time!


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