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Cell Division. By: Amber Tharpe. Activation. Humans make 2 trillion new cells per day. Cell Cycle. 2 main parts Interphase- Cell is normal Mitosis- Cell is dividing Cytokinesis- occurs at the end of mitosis. Mitosis. Divides DNA into 2 nuclei Makes 2 daughter cells with a diploid number
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Cell Division By: Amber Tharpe
Activation • Humans make 2 trillion new cells per day
Cell Cycle • 2 main parts • Interphase- Cell is normal • Mitosis- Cell is dividing • Cytokinesis- occurs at the end of mitosis
Mitosis • Divides DNA into 2 nuclei • Makes 2 daughter cells with a diploid number • Used for growth and repair • Also used in some asexual reproduction
4 stages (P-M-A-T) Prophase Metaphase Anaphase Telophase
Stages of Mitosis (P-M-A-T) Prophase Early Prophase Interphase http://micro.magnet.fsu.edu/micro/gallery/mitosis/mitosis.html Metaphase Early Anaphase Telophase Anaphase
Prophase DNA condenses Nuclear envelope dissolves Spindle fibers start to form
Metaphase Chromosomes align in the middle of the cell (equator) Spindle fibers attach to the chromosomes to move them
Anaphase Chromosomes separate to opposite poles Spindle fibers split chromosomes in half
Telophase • 2 nuclear envelopes form around the separated DNA • Spindle fibers dissolve • In animal cells • Cell membrane pinches in • In plant cells • Cell plate forms which later becomes 2 cell walls
Cytokinesis Cytoplasm and organelles divide 2 cells form
http://www.classzone.com/cz/books/bio_07/get_chapter_group.htm?cin=2&rg=animated_biology&at=animated_biology&var=animated_biologyhttp://www.classzone.com/cz/books/bio_07/get_chapter_group.htm?cin=2&rg=animated_biology&at=animated_biology&var=animated_biology
Animation of Stages of Mitosis http://biology.about.com/library/blmitosisanim.htm
Asexual Reproduction 1 parent Offspring is identical to parent Less genetic diversity
Binary Fission Asexual reproduction for bacteria DNA is copied in 1 cell The cell divides into 2 cells with the same DNA
http://www.classzone.com/cz/books/bio_07/get_chapter_group.htm?cin=2&rg=animated_biology&at=animated_biology&var=animated_biologyhttp://www.classzone.com/cz/books/bio_07/get_chapter_group.htm?cin=2&rg=animated_biology&at=animated_biology&var=animated_biology
Chromosome Long thread of DNA containing many genes X- shaped
Somatic cells Body cells All cells not involved in reproduction Diploid cells (2N) Contains 2 copies of each chromosome In humans 46 chromosomes Made by mitosis
Gametes Sex cells Egg (female) or sperm (male) Haploid cells (1N) Contains 1 copy of each chromosome In humans 23 chromosomes Made by meiosis Used in sexual reproduction
Sex Chromosomes Chromosome pair 23 for gender Either X or Y XX is female XY is male
Sexual Reproduction Offspring are a mixture of both parents Occurs by meiosis then fertilization Meiosis Formation of gametes Makes haploid cells from diploid cells Fertilization The actual fusion of the 2 gametes First cell is called a zygote
Meiosis Process of making gametes for sexual reproduction Events that occur during meiosis allows for greater genetic diversity
Meiosis Meiosis I Makes 2 unique diploid cells Prophase I – Telophase I Interphase without duplicating DNA Meiosis II Makes 4 unique haploid cells Prophase II – Telophase II
Crossing Over Occurs in Prophase I Homologous chromosomes line up and sections of the chromosomes overlap and become incorporated into the other Allows for genetic diversity
Independent Assortment Occurs in Metaphase I Independent Assortment Allows for genetic variation When homologous chromosomes line up in the middle, some chromosomes from the mother and father line up on either side
Telophase II Produces 4 haploid cells with unique combinations of chromosomes Females produce 1 ovum (egg) and 3 polar bodies Males produce 4 sperm cells