Mitosis

Mitosis

Mitosis is a process of cell division

Goal = production of 2 daughter cells.

The daughter cells are identical to one another and to the original parent cell.

Cells divide for growth or Cells divide for growth or repair. repair.

Before each division, the Before each division, the cell makes an identical copy cell makes an identical copy of each chromosomeof each chromosome

During mitosis, each of the During mitosis, each of the two new cells receives a two new cells receives a complete set of 46 complete set of 46 chromosomes.chromosomes.

Identical meaning it has the Identical meaning it has the same info.same info.

Stages

InterphaseInterphase ProphaseProphase PromatophasePromatophase MetaphaseMetaphase Anaphase Anaphase TelophaseTelophase

Interphase

Preparing with mitosisPreparing with mitosis The cell is engaged in The cell is engaged in

metabolic activitymetabolic activity Nucleolus may be Nucleolus may be

visible.visible. The cell may contain The cell may contain

a pair of centriolesa pair of centrioles

Prophase Chromatin in the nucleus begins Chromatin in the nucleus begins

to condense and becomes visible to condense and becomes visible Each chromosome has duplicated has duplicated Consists of two sister chromatids. Consists of two sister chromatids. The nucleolus/nuclear envelope The nucleolus/nuclear envelope

disappears.disappears. Centrioles begin moving to Centrioles begin moving to

opposite ends of the cell and opposite ends of the cell and fibers extend from the fibers extend from the centromeres. centromeres.

Some fibers cross the cell to form Some fibers cross the cell to form the mitotic spindle. the mitotic spindle.

Prometaphase

Proteins attach to the Proteins attach to the centromeres creating centromeres creating the kinetochores.the kinetochores.

Microtubules attach at Microtubules attach at the kinetochoresthe kinetochores

Chromosomes begin Chromosomes begin moving. moving.

Metaphase• Spindle fibers align the Spindle fibers align the

chromosomes along the middle of chromosomes along the middle of the cell nucleus (metaphase the cell nucleus (metaphase plate/equitorial). plate/equitorial).

• This organization helps to ensure This organization helps to ensure that in the next phase, when the that in the next phase, when the chromosomes are separated, each chromosomes are separated, each new nucleus will receive one new nucleus will receive one copy of each chromosome.copy of each chromosome.

• Held in place by microtubules Held in place by microtubules attached to the mitotic spindle. attached to the mitotic spindle.    

Anaphase

• The paired chromosomes The paired chromosomes separate at the kinetochores separate at the kinetochores and move to opposite sides and move to opposite sides of the cell.of the cell.

• The centromeres divide. The centromeres divide. • Sister chromatids separate Sister chromatids separate

and move toward the and move toward the corresponding poles. corresponding poles.    

Telophase Chromatids (daughter Chromatids (daughter

chromosomes) arrive at chromosomes) arrive at opposite poles of cellopposite poles of cell

New membranes form New membranes form around the daughter nuclei. around the daughter nuclei.

The chromosomes disperseThe chromosomes disperse No longer visible under the No longer visible under the

light microscope. light microscope. Microtubules disappear. Microtubules disappear. The condensed chromatin The condensed chromatin

expandsexpands Nuclear envelope Nuclear envelope

reappears. reappears.

Cytokinesis

Results when a fiber Results when a fiber ring composed of a ring composed of a protein called actin protein called actin around the center of the around the center of the cell contracts pinching cell contracts pinching the cell into two the cell into two daughter cells, each daughter cells, each with one nucleus. with one nucleus.

Mitosis in general

Summary

Mitosis vs Meiosis