Cell CycleCell Cycle 3 Steps

Interphase

cell growth and development

Longest phase

Mitosis

cell reproduction creating 2 new nuclei

Cytokinesis

cell reproduction finishes

creating 2 new cells (DAUGHTER)

Importance of Cell Division

• Some cells get old and wear out

• New cells formed by the cell cycle replace old cells before they die– For example: every human is shedding old

skin cells. We loose about 40,000 cells every minute.

– Cells lining the stomach are replaced every week because your stomach is so acidic

• New cells formed by the cell cycle replace old cells before the cell dies.

Vocabulary Preview

• Cell Cycle• Interphase• Mitosis

– Prophase– Metaphase– Anaphase– Telephase

• Cytokinesis

• Homologous Chromosome

• Daughter Cell• Sister Chromatid• Centromere• Cell Plate

http://www.teachersdomain.org/asset/lsps07_int_devdance/

Length of a Cell Cycle• The length of a cell cycle is different for each type

of organism and every different type of cell (skin, heart, lung, etc…)

• When organisms are young and growing, the cell cycle repeats more quickly.– An example: A zebra fish grows from 1 cell to 256 cells in 15

minutes

Preview Cell Division

• http://iknow.net/player_window.html?url=media/cell_cycle_intro_auto.swf&width=360&height=285– Enlarge Screen for a bigger view

Phases of the Cell Cycle

RESULTS OF CELL DIVISION

•After Mitosis and Cell Division, the original cell, called the parent cell NO LONGER EXISTS•After the cell cycle (at the end of cytokinesis) 2 new identical cells (called Daughter cells) are created. They are genetically identical to the parent cell.

•Think Write Pair Share: What happened to the original parent cell?

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Interphase

• First Phase of the Cell Cycle

• Chromosomes (which is another name for the DNA) in the nucleus are like a bunch of spaghetti noodles.

• For each chromosome there is an identical chromosome. This identical pair is called homologous chromosomes.

• Humans have 23 pairs of homologous chromosomes.

Phase in Interphase• Interphase has three phases G1, S, and G2.

G1 Cells grow perform cell functions (do their job)

S Cells growperform cell functions (do their job)DNA is copied

G2 Cells growperform cell functions (do their job), all organelles are copied

Mitosis2nd part of the Cell Cycle

• Mitosis is a continuous process.

PMAT• It is made up of 4 phases

– Prophase– Metaphase– Anaphase– TelophasePREVIEW: http://highered.mcgraw-hill.com/sites/0073031216/student_view0/exercise13/mitosis_movie.html

Prophase

The first phase of mitosis is Prophase.

1) Chromosomes (DNA) twist (condense) into tight coils

2) Nucleus breaks apart

Metaphase

During Metaphase, all the chromosomes that are attached to the fibers move to the middle of the cell.

The pairs line up end to end, across the center of the cell.

“Meet in the middle”

AnaphaseDuring Anaphase, The chromosomes are pulled apart making 2 sister chromatids.

The sister chromatids are pulled to opposite sides of the cell

http://www.copernicusproject.ucr.edu/ssi/HSBiologyResources.htm

Telophase

During Telophase, a new nuclear membrane forms around the separated chromatids making 2 identical nuclei in 1 cell.

http://www.cellsalive.com/mitosis.htm

Cytokinesis

Cytokinesis

Viewing Cell DivisionCell Cycle, Animal Mitosis, & Plant Mitosis

Mitosis: http://www.iknow.net/player_window.html?url=media/prophase_video_auto.swf&width=360&height=285

Plant Cell Mitosis:

http://www.iknow.net/player_window.html?url=media/plant_mitosis_auto.swf&width=360&height=285

Microscopic:http://www.teachersdomain.org/asset/tdc02_vid_dnadivide/

Hand Drawn:http://www.layyous.com/Videoclips/mitosis.htm

Living Cell-Time lapse photography:http://www.phschool.com/science/biology_place/labbench/lab3/mitfilm.html

Writing to Learn

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