what’s the point??? asexual reproduction…. three reasons why cells reproduce by asexual...

What’s the point???What’s the point???

Asexual Reproduction…Asexual Reproduction…

Three reasons why cells reproduce by asexual reproduction: 1. Growth 2. Repair 3. ReplacementCell that reproduce by asexual reproduction reproduce constantly. Skin cancer - the abnormal growth of skin cells - most often develops on skin exposed to the sun.

Two Basic Types of Cells – Quick ReviewTwo Basic Types of Cells – Quick Review

Prokaryote

Eukaryote

Asexual Reproduction in Asexual Reproduction in Prokaryotes = Binary FissionProkaryotes = Binary Fission

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Asexual ReproductionEukaryotes = Mitosis

Adapted, In part, from Mrs. Camp

7th Grade Life Science

Cell Life Cycle - Overviewhttp://www.cellsalive.com/mitosis.htm

• Interphase

• Prophase (mitosis)

• Metaphase (m)

• Anaphase (m)

• Telophase (m) & Cytokinesis

http://www.biology.arizona.edu/Cell_bio/tutorials/cell_cycle/mitosis_movie.html

Interphase occurs before mitosis begins

• Chromosomes are copied (# doubles)• Chromosomes appear as threadlike coils

(chromatin) at the start, but each chromosome and its copy(sister chromosome) change to sister chromatids at end of this phase

CELL MEMBRANENucleus

Cytoplasm

InterphaseInterphase

Animal Cell Plant Cell

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

Prophase 1st step in Mitosis

• Mitosis begins (cell begins to divide)• Centrioles (or poles) appear, divide and begin to move to opposite end of the cell. • Spindle fibers form between the poles.• Chromosomes(Chromatin)begin to coil around a spindle shaped protein and become ChromatidsNuclear membrane begins to break apart

CentriolesSister chromatids

Spindle fibers

Chromatids - ProfilesChromatids - Profiles

ProphaseProphase

Animal Cell Plant Cell

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

Spindle fibers

Centrioles

Metaphase 2nd step in Mitosis

• Chromatids (or pairs of chromosomes) attach to the spindle fibers.

Centrioles

Spindle fibers

MetaphaseMetaphase

Animal Cell Plant Cell

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

Anaphase 3rd step in Mitosis

• Chromatids (or pairs of chromosomes) separate and begin to move to opposite ends of the cell.

Centrioles

Spindle fibers

AnaphaseAnaphase

Animal Cell Plant Cell

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

Telophase 4th step in Mitosis

• Two new nuclei form. • Chromosomes appear as chromatin (threads

rather than rods).• Mitosis ends.

NucleiNuclei

Chromatin

TelophaseTelophase

Animal Cell Plant Cell

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

Cytokinesisoccurs after mitosis

• Cell membrane moves inward to create two daughter cells – each with its own nucleus with identical chromosomes.

Animal Mitosis -- Review

Interphase

Prophase

Metaphase

Anaphase

Telophase

Interphase

Plant Mitosis -- ReviewInterphase

Prophase

Metaphase

Anaphase

Telophase

Interphase

How much time is in each phase?How much time is in each phase?

The Most Time is in the INTERPHASE The Most Time is in the INTERPHASE – (G1, S & G2)– (G1, S & G2)

Time to Play (or Make a Play)Time to Play (or Make a Play)

ROLESChromosomes (4)

(later Chromatids – must have belts)

Centrioles (2)Nuclear Membrane

(6)Cell Membrane (16)Golgi Body (2)Mitochondria (2)

Action PartReplicate and divide

Pull apart the sister chromatids

Dissolve and reappear

Divide along equator of cell

Move into your new homes

Cell CycleCell Cycle

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The Cell CycleThe Cell Cycle

25

- Cell Division

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Mitosis AnimationMitosis Animation

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

http://www.biology.arizona.edu/Cell_bio/tutorials/cell_cycle/mitosis_movie.html

Song Challenge…Song Challenge…

SONG TIME: http://www.teachertube.com/viewVideo.php?video_id=81750

What differs between plant cell What differs between plant cell and animal cell mitosis?and animal cell mitosis?

How are mitosis and binary fission How are mitosis and binary fission different?different?

Meiosis KM 30

Asexual Reproduction – So Cool!Asexual Reproduction – So Cool!Common Types:1. Splitting2. Budding3. Parthenogenesis4. Fragmentation◦Almost all single-celled

organisms reproduce asexually.

◦Some multicellular organisms can reproduce asexually too, produce clones (offspring genetically identical to parent).

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3

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ReferencesReferences

3. GIF of binary fission is from: http://www.slic2.wsu.edu:82/hurlbert/micro101/pages/Chap2.html#two_bact_groups

2. http://library.thinkquest.org/12413/karyotes.html

1.http://74.125.113.132/search?q=cache:PKemMRTlT_kJ:sciencespot.net/Media/mitosisPPT.ppt+mitosis+powerpoint&cd=1&hl=en&ct=clnk&gl=us&client=firefox-a

4.http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookmito.html