MITOSISMITOSIS

The Cell CycleThe Cell Cycle

Interphase: Interphase: in between stages of dividingin between stages of dividing G1—beginning cell growthG1—beginning cell growth S—DNA duplicates (makes a S—DNA duplicates (makes a

copy)copy) DNA is in the form of DNA is in the form of chromatinchromatin G2—cell undergoes it’s functionG2—cell undergoes it’s function

Purpose: Purpose: to replace dead or dying cellsto replace dead or dying cells to allow an organism to grow to allow an organism to grow

and develop and develop

MitosisMitosis

Mitosis animation:Mitosis animation: http://www.youtube.com/watch?v=2WwIKdyBN_s&feature=related

Mitosis:Mitosis:

What is it basically? What is it basically? DNA copies (chromosomes) are separated & DNA copies (chromosomes) are separated &

sorted into two sides of the cellsorted into two sides of the cell

the cell then splits in two and part of each the cell then splits in two and part of each parent is carried to the two new cells. parent is carried to the two new cells.

each ‘daughter’ cell is identical to the parent each ‘daughter’ cell is identical to the parent cellcell

results in cells such as internal organs, skin, results in cells such as internal organs, skin, bones, blood, etc. bones, blood, etc.

VocabularyVocabulary

InterphaseInterphase ProphaseProphase MetaphaseMetaphase Anaphase Anaphase TelophaseTelophase CytokinesisCytokinesis

Interphase Interphase occurs just before occurs just before Mitosis begins:Mitosis begins:

DNA is replicated along with organelles and other cellular components and the cell prepares for division.

http://www.bioweb.uncc.edu/1110Lab/notes/notes1/lab6.htm

An Electron An Electron Microscope Microscope Image of Image of

Duplicated Duplicated Pair of Pair of

ChromosomChromosomeses

MitosisMitosis Interphase Interphase

Animal cellAnimal cell Plant cellPlant cell

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

11stst step in Mitosis: step in Mitosis: Prophase (preparation phase)Prophase (preparation phase)

http://www.bioweb.uncc.edu/1110Lab/notes/notes1/lab6.htm

•the DNA recoils, and the chromosomes condense•the nuclear membrane disappears•mitotic spindles begin to form.

MitosisMitosis Prophase Prophase

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

Animal cellAnimal cell Plant cellPlant cell

22ndnd step in Mitosis: step in Mitosis:Metaphase (organizational Metaphase (organizational

phase)phase) spindle fibres spindle fibres

attach to the attach to the chromosomes at chromosomes at the centromerethe centromere

chromosomes chromosomes line up the line up the middle of the cellmiddle of the cell

http://www.bioweb.uncc.edu/1110Lab/notes/notes1/lab6.htm

MitosisMitosis Metaphase Metaphase

Animal cellAnimal cell Plant cellPlant cell

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

33rdrd step in Mitosis: step in Mitosis: Anaphase (separation phase)Anaphase (separation phase)

the the chromosomes chromosomes split at the split at the centromerecentromere

the ‘sister the ‘sister ‘chromatids are ‘chromatids are pulled by the pulled by the spindle fibers to spindle fibers to opposite poles of opposite poles of the cell. the cell.

http://www.bioweb.uncc.edu/1110Lab/notes/notes1/lab6.htm

MitosisMitosis Anaphase Anaphase

Animal cellAnimal cell Plant cellPlant cell

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

44thth step in Mitosis: step in Mitosis: TelophaseTelophase

the chromosomes, the the chromosomes, the cytoplasm and cytoplasm and organelles divide into 2 organelles divide into 2 portions. portions. 

this diagram shows the this diagram shows the end of telophase.end of telophase.

http://www.bioweb.uncc.edu/1110Lab/notes/notes1/lab6.htm

MitosisMitosis Telophase Telophase

Animal cellAnimal cell Plant cellPlant cell

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

After Mitosis:After Mitosis: CytokinesisCytokinesis

the actual splitting the actual splitting of the daughter of the daughter cells into two cells into two separate cells is separate cells is called called cytokinesiscytokinesis

occurs differently in occurs differently in

both plant and animalboth plant and animal

cells. cells.

(Cleavage in animals, (Cleavage in animals, cell wall in plantscell wall in plants))

Beginning of cytokinesis in a plant:

Beginning of cytokinesis in an animal:

http://www.bioweb.uncc.edu/1110Lab/notes/notes1/lab6.htm

WHICH STAGE ARE THESE CELLS WHICH STAGE ARE THESE CELLS IN?IN?

MitosisMitosis

Mitosis animations:Mitosis animations: http://www.youtube.com/watch?v=2WwIKdyBN_s&feature=related http://www.youtube.com/watch?v=VlN7K1-9QB0

MITOSIS ANIMATIONMITOSIS ANIMATION

Look at the next few slides in quick succession to see

an almost animated plant

mitosis sequence.