CELL DIVISION!!

There are two types of cell division.

Mitosis – when an organism is growing, repairing or replacing cells

EX: skin cells replacing dead skin cells

Meiosis – division of reproductive cells

Meiosis or Mitosis?

A) A snake sheds its skin.B) My dog just had puppies.C) You grew four inches in the last 2 years.

MITOSIS

Mitosis Cycle

• Interphase

• Prophase

• Metaphase

• Anaphase

• Telophase

• Cytokinesis

http://www.youtube.com/watch?v=NR0mdDJMHIQ&feature=related

Interphase

• The cell prepares to divide by copying its DNA

Interphase

Animal Cell Plant Cell

Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

Prophase

• The chromatin in the nucleus condenses and forms chromosomes.

• Centrioles appear at the poles of the cell.

• The nuclear envelope breaks down.

Prophase

Animal Cell Plant Cell

Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

Metaphase

• The centrioles attach spindle fibers to the centers of each chromatid (a pair of chromosomes)

• The chromatids are being pulled in both directions, so they end up lined up across the center of the cell.

Metaphase

Animal Cell Plant Cell

Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

Anaphase 3rd step in Mitosis

• The chromatids split up; half moving toward one pole and the other half moving toward the other pole.

• The cell begins to stretch.

Anaphase

Animal Cell Plant Cell

Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

Telophase

• Two new nuclear envelopes form.

• The chromatids loosen up and appear as chromatin again

Cytokinesis

• The cell membrane pinches into two ‘daughter cells’ that are exactly the same as the ‘parent cell.’

Animal Mitosis -- Review

Interphase

                                              

              

Prophase

                                             

               

Metaphase

                                              

              

Anaphase

                                             

               

Telophase

                                              

              

Interphase

                                             

               

Plant Mitosis -- ReviewInterphase

                                                        

    

Prophase

                                                       

     

Metaphase

                                                        

    

Anaphase

                                                       

     

Telophase

                                                        

    

Interphase

                                                       

     

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Cell Cycle