Mitosis and MeiosisMitosis and Meiosis

By Andrew StoneBy Andrew StonePeriod: 2Period: 2

Life Science TopicLife Science TopicCompare sexual reproduction (offspring Compare sexual reproduction (offspring inherit half of their genes from each inherit half of their genes from each parent) with asexual reproduction parent) with asexual reproduction (offspring is an identical copy of the parent (offspring is an identical copy of the parent cell).cell).

What is Mitosis?What is Mitosis?The process by which one copy of a The process by which one copy of a parent cell’s DNA is copied into each of parent cell’s DNA is copied into each of the 2 identical daughter cells.the 2 identical daughter cells.

How it happens?How it happens?The parent cell’s chromosomes double The parent cell’s chromosomes double and then divide into each of the 2 identical and then divide into each of the 2 identical daughter cellsdaughter cells

Stages of MitosisStages of MitosisInterphase:Interphase:

Spends most of cell life Spends most of cell life in this phase.in this phase.

Cell prepare for division Cell prepare for division in this phase.in this phase.

ProphaseProphasechromatin condenses into chromosomes. chromatin condenses into chromosomes. The nuclear envelope breaks down The nuclear envelope breaks down spindles form at opposite ends of the cell. spindles form at opposite ends of the cell.

MetaphaseMetaphasethe spindle fully develops and the the spindle fully develops and the chromosomes align at the middle of chromosomes align at the middle of spindle fibersspindle fibers

AnaphaseAnaphaseIn anaphase, the paired chromosomes separate and In anaphase, the paired chromosomes separate and begin moving to opposite ends of the cell. Spindle fibers begin moving to opposite ends of the cell. Spindle fibers not connected to chromatids lengthen and elongate the not connected to chromatids lengthen and elongate the cell. At the end of anaphase, each pole contains a cell. At the end of anaphase, each pole contains a complete set of chromosomes. complete set of chromosomes.

TelophaseTelophaseThe cell continues to lengthen.The cell continues to lengthen.Nuclei begin to form at opposite ends.Nuclei begin to form at opposite ends.The nuclear envelopes of these nuclei are formedThe nuclear envelopes of these nuclei are formedNucleoli also reappear.Nucleoli also reappear.Chromatin fibers of chromosomes uncoil.Chromatin fibers of chromosomes uncoil.

CytokinesisCytokinesisDuring cytokinesis, the cytoplasm of a cell is During cytokinesis, the cytoplasm of a cell is physically divided to form two daughter cellsphysically divided to form two daughter cells

The binding of some molecules or organelles to The binding of some molecules or organelles to the chromosomes or spindle fibers ensures that the chromosomes or spindle fibers ensures that each daughter cell will receive a fair share of each daughter cell will receive a fair share of components.components.

Mitosis LinksMitosis LinksMitosis and CytokinesisMitosis and CytokinesisMeiosis AnimationMeiosis Animation

What is Meiosis?Not to be confused with mitosisThe process by which the number of chromosomes is reduced by half to form sex cells (sperm and egg)

Why?Sex cells have half the chromosomes that body cells have so that when the sperm and the egg combine in the zygote, the zygote will have the right number of chromosomes.

How?The double in the parent cell then the parent cell divides just like in mitosis except twice to produce 4 sex cells

Stages of MeiosisThe stages of meiosis are similar to those of mitosis except there are extra stages for the second division and in prophase some chromosomes swap genesThe next slide shows 2 diagrams of the mechanics of meiosis and the stages of meiosis

Meiosis Links

Interactive activity Meiosis Matching

Recommended Extra Activities

Read Read All about Mitosis and Meiosis All about Mitosis and Meiosis by by Elizabeth R. C. CreganElizabeth R. C. CreganAlso, try one of these fun activities…

Paraphased By Andrew StoneParaphased By Andrew Stone    1.Newspaper article1.Newspaper article – Write an article from the point of view of a person living during the discoveries of mitosis and – Write an article from the point of view of a person living during the discoveries of mitosis and meiosis. Answer the “who, what, when, where and why” questions. Your article must be supported by pictures with meiosis. Answer the “who, what, when, where and why” questions. Your article must be supported by pictures with captions. captions.   2. Poem or song2. Poem or song – Write an original poem or song explaining the steps of mitosis and meiosis. – Write an original poem or song explaining the steps of mitosis and meiosis.

3. Create a model of both mitosis and meiosis3. Create a model of both mitosis and meiosis – Demonstrate the steps of mitosis and meiosis by creating a model of – Demonstrate the steps of mitosis and meiosis by creating a model of these processes. The model must be accurate, demonstrate knowledge, and be a creative design. It must be 3D . these processes. The model must be accurate, demonstrate knowledge, and be a creative design. It must be 3D .   4. Write a children’s storybook4. Write a children’s storybook – Write an original story explaining the steps of mitosis and meiosis. The story must – Write an original story explaining the steps of mitosis and meiosis. The story must include all the parts of a story including characters, plot, dialogue, descriptions and illustrations. include all the parts of a story including characters, plot, dialogue, descriptions and illustrations.

5. Political cartoon5. Political cartoon – You must create a political cartoon strip showing the steps of mitosis and meiosis. The cartoon must – You must create a political cartoon strip showing the steps of mitosis and meiosis. The cartoon must include colored drawings and captions. include colored drawings and captions.   6. Animated FlipBook6. Animated FlipBook – You must create a flip book depicting mitosis and meiosis that will show the stages of each – You must create a flip book depicting mitosis and meiosis that will show the stages of each process when flipped. Each page must have a picture (colored), as well as a description of what is happening. At the end process when flipped. Each page must have a picture (colored), as well as a description of what is happening. At the end of the book, you must write a comparison and contrast of the two processes. of the book, you must write a comparison and contrast of the two processes.   Sources: Pebble Brook High School Web SiteSources: Pebble Brook High School Web Site

SourcesSources

Ask.About.com:BiologyAsk.About.com:BiologyEncyclopedia.comEncyclopedia.comPicsearchPicsearchYou Tube You Tube Cells AliveCells AliveClip Art Clip Art

THE END!THE END!