Cell Division

• Cell Division


  The division of a cell into two daughter cells with the same genetic material.
• MAIN PARTS OF THE CELL:

  1. Cell Membrane - protects the interior of cell
  2. Cytoplasm - A jelly like substance that functions like a cushion for the cell's genetic material. It provides the shape of the cell.
  3. Nucleus - the control center of cell. It holds the DNA which it holds the chromosomes
• STRUCTURES OF CELL DIVISION THAT ARE NEED FOR IT:

  • Centrioles - produces the spindle fibers
  • Nucleus - holds the DNA, the DNA holds the chromosomes
• IMPORTANCE OF CELL DIVISION:

  1. It is the producer of haploid cells for sex cells
  2. For growth
  3. Repair damaged or dead cells
  4. Reproduce and create identical copies of themselves
• TWO TYPES OF CELL DIVISION:

  • Mitosis - happens in the body
  • Meiosis - happens in the sex/reproductive cells
• Mitosis

  • 23 pair
  • 46 in total
  • Diploid cells
  • Ends with 2 daughter cells
• Meiosis

  • 23 pairs
  • 46 in total
  • Haploid
  • Ends with 4 daughter cells
• Cell Cycles


  the series of events that take place in a cell
• TWO MAIN STAGES OF THE CELL CYCLE:

  Interphase (The longest phase of the cell cycle in which a cell copies its DNA to prepare for mitosis) and Mitotic Phase (the cell divides its copied DNA and cytoplasm to make two new cells)
• G0 phase 


  The resting phase of the cell cycle
• Tumor


  uncontrolled growth of cell
• Cytokinesis


  When the cytoplasm divides
• Karyokinesis


  When the nucleus divides
• Centromeres 


  connects sister chromatids
• Mitosis

  • Prophase (Chromosomes condense and the nuclear envelop breakdown)
  • Metaphase (Chromosomes align at the middle of the cell)
  • Anaphase (centromeres divide)
  • Telophase (when the chromosomes move in opposite directions or the cytoplasm divides)
• Meiosis

  • Homologous pair - each chromosome in pair are identical to the other
  • XX - Female
  • XY - Male
  • Synapsis - pairing of homologous chromosomes forming a tetrad.
• Meiosis I

  • Prophase I (The chromosomes condense, and the nuclear envelope breaks down, crossing-over occurs)
  • Metaphase I (pairs of homologous chromosomes move at the middle of the cell)
  • Anaphase I (Homologous chromosomes move to the opposite poles of cells)
  • Telophase I (Chromosomes gather at the poles of the cells. The cytoplasm divides. Ends with 2 new cells)
• Meiosis II

  • Prophase II (A new spindle forms around the chromosomes)
  • Metaphase II (chromosomes line up at the equator of the middle of the cell)
  • Anaphase (Centromeres divide. Chromatids move to the opposite poles of the cells)
  • Telophase II (A new nuclear envelope forms around each set of chromosomes. The cytoplasm divides.)