Mitosis and meiosis

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

Mitosis: If a cell wants to make a duplicate of itself, it first must copy its DNA (part of a chromosome). The copies then must be separated & sorted into two sides of the cell. The cell then splits in two. Part of each parent is carried to the two new cells. Results in cells such as internal organs, skin, bones, blood, etc.

Meiosis: As in mitosis, if a cell wants to make a duplicate of itself, it first must copy its DNA (part of a chromosome). Results in reproductive cells (sperm, eggs, etc). Part of each parent is carried to the four new cells. Meiosis has evolved to solve a problem. The problem is this: some organisms have sex with other organisms – that is, they combine their genes together (creating genetic diversity). Why would this be a problem?

This may you remember these terms: MIT osis takes the cell and M akes I t T wo (diploid) M e iosis has to do with s e x From the cell’s point of view: m IT osis results in I dentical T wins m E io S is results in E gg and S perm (haploid) Clyde Freeman Herreid – Dept. of Biological Sciences: Buffalo State Univ. of New York

Mitosis: Meiosis: Each resulting cell still has chromosomes from mom & dad

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

Vocabulary Diploid Haploid Interphase Prophase Metaphase Anaphase Telophase Cytokinesis

Interphase occurs just before 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

Mitosis Interphase Animal cell Plant cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

1 st step in Mitosis: Prophase (preparation phase) http://www.bioweb.uncc.edu/1110Lab/notes/notes1/lab6.htm The DNA recoils, and the chromosomes condense; the nuclear membrane disappears, and the mitotic spindles begin to form.

Mitosis Prophase Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm Animal cell Plant cell

2 nd step in Mitosis: metaphase (organizational phase) The chromosomes line up the middle of the cell with the help of spindle fibers attached to the centromere of each replicated chromosome. http://www.bioweb.uncc.edu/1110Lab/notes/notes1/lab6.htm

Mitosis Metaphase Animal cell Plant cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

3 rd step in Mitosis: Anaphase (separation phase) The chromosomes split in the middle and the sister chromatids are pulled by the spindle fibers to opposite poles of the cell. http://www.bioweb.uncc.edu/1110Lab/notes/notes1/lab6.htm

Mitosis Anaphase Animal cell Plant cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

4 th step in Mitosis: Telophase The chromosomes, along with the cytoplasm and its organelles and membranes are divided into 2 portions. This diagram shows the end of telophase. http://www.bioweb.uncc.edu/1110Lab/notes/notes1/lab6.htm

Mitosis Telophase Animal cell Plant cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

After Mitosis: Cytokinesis The actual splitting of the daughter cells into two separate cells is called cytokinesis and occurs differently in both plant and animal Cells. Beginning of cytokinesis in a plant: Beginning of cytokinesis in an animal: http://www.bioweb.uncc.edu/1110Lab/notes/notes1/lab6.htm

I nterphase P rophase M etaphase A naphase T elophase C ytokinesis I P ray M ore A t T he C hurch Julie Camp’s mitosis power point - http://sciencespot.net/Pages/classbio.html#Anchor-mitosis IPMATC

Meiosis Meiosis animation: http://www.youtube.com/watch?v=D1_-mQS_FZ0&NR=1

Vocabulary Diploid Haploid Germ cell Somatic cell Interphase Prophase Metaphase Anaphase Telophase Cytokinesis

Meiosis Interphase Meiosis is preceded by interphase. The chromosomes have not yet condensed. http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

Meiosis Interphase The chromosomes have replicated, and the chromatin begins to condense. http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

Meiosis Prophase I The chromosomes are completely condensed. In meiosis (unlike mitosis), the homologous chromosomes pair with one another http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

Meiosis Metaphase I The nuclear membrane dissolves and the homologous chromosomes attach to the spindle fibers. They are preparing to go to opposite poles. http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

Meiosis Anaphase I The chromosomes move to opposite ends of the cell. http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

Meiosis Telophase I & Cytokinesis The cell begins to divide into two daughter cells. It is important to understand that each daughter cell can get any combination of maternal and paternal chromosomes. http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

Meiosis Prophase II The cell has divided into two daughter cells. http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

Meiosis Metaphase II As in Meiosis I, the chromosomes line up on the spindle fibers. http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

Meiosis Anaphase II The two cells each begin to divide. As in Meiosis I, the chromosomes move to opposite ends of each cell. http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

Telophase II & Cytokinesis With the formation of four cells, meiosis is over. Each of these prospective germ cells carries half the number of chromosomes of somatic cells. http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

Yvonne Norman G410 (Life Sciences for Middle School Educators) Senior – Portland State University February 2009

Mitosis and meiosis

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