- Slides: 15
Mitosis and Cell Division Chapter 8
Before division All cells must grow before thinking about replicating. If a cell does not increase in size, when it doubles the new little cells will not be large enough to survive. In cell division cells must rest, then enlarge in size before the DNA can replicate to get ready to double and split.
Mitosis Interphase – this is what happens between cell divisions. Often called the resting phase.
Mitosis Prophase – this is the 1 st stage of mitosis, when the cell doubles all of it’s important structures. Chromosomes shorten and coil and then double themselves. All organelles double as well and the cell gets much larger in size. The nuclear membrane disappears. Centromeres are visible and the spindle fibers begin to form. In animals cells the centrioles form, in plant cells the astors form.
Mitosis Metaphase - The chromosomes are now very easy to see. They line up at the center of the big cell in pairs. The spindle fibers attach to the centromeres of the chromosomes and fine lines are seen leading to the “poles” of the cell. All organelles now are on either the northern hemisphere or the southern hemisphere.
Mitosis Anaphase - At this point in the mitosis process the pairs of chromosomes pull apart to the poles (either side of the cell) All organelles move to one side or the other and begin to get ready for the cell to divide.
Mitosis Telephase - here the cell begins to “pinch-in” in the middle of the cell. This is the beginning of cytokinesis which is the division of the cytoplasm of the cell. All material moves to the center of the cell and the nuclear membrane re-appears and re-forms. A new cell membrane is closed all around the cell(s).
Mitosis Daughter cells - This is the last stage of mitosis and here the final stage shows two exact replicates of the first cell. All with the same DNA and the same organelles as the first. In plant cells the new cell wall is seen here as a complete line between two little cells.
Class work Draw and label the stages of mitosis and the cell cycle in color Read Pages 151 -158 Due Today! 100 points Interphase* Telephase Prophase Daughter Cells* Metaphase (cytokinesis) Anaphase