230 likes | 469 Views
Meiosis 2C or not 2C. What is meiosis?. A) A fancy dish served at Asian Fusion restaurants. B) The name of the newest singing sensation. C) The process by which haploid cells called gametes are formed. Why is meiosis important?. A) Just because it is.
E N D
What is meiosis? A) A fancy dish served at Asian Fusion restaurants. B) The name of the newest singing sensation. C) The process by which haploid cells called gametes are formed.
Why is meiosis important? A) Just because it is. B) It allows the chromosome number to be halved. C) Yo no se!
What is involved in meiosis? • A series of steps similar to mitosis. B) Haploid cells (gametes). • A lot of vowels. • Both A and B are correct.
What is a haploid cell? • A cell that is happy. • A sex cell—egg or sperm. • A cell that has half the number of chromosomes as a somatic (body) cell. • Both B and C are correct.
Meiosis: The Facts • Process resulting in formation of reproductive cells. • Occurs using similar steps as mitosis. • End product is 4 genetically different haploid cells. • Haploid cells are 1C. • Diploid cells are 2C. • Occurs in two stages—Meiosis I and Meiosis II. • Meiosis I – separates the tetrad resulting in TWO cells. • Meiosis II – separates the sister chromatids resulting FOURcells.
Meiosis – The Cast Homologous Chromosomes – (AKA Tetrad) • pairs of similar but not identical chromosomes. • They code for the same characteristic. • One is inherited from mother (pink) and other from father (blue).
Homologous Shoes? • Look at your shoes. • How can they compare to homologous chromosomes? • Sisters • Similar but not identical • (left and right shoes) • All shoes (in class) • No two pairs are identical • Unique pairs of chromosomes in the cells
Meosis – The Cast • Chromatin – packed genetic material • From oodle noodle to bow pasta!
Meiosis – The Cast Sister Chromatids = one complete chromosome • Chromatid • Centromere • Short-Arm of chromatid • Long-Arm of chromatid
Meiosis – The Cast • Tetrad –formed during meiosis I. • These are PAIR of sister chromatids. • Called a tetrad because there are FOUR chromatids present. • “Swapping” of genetic material between chromosomes occurs between tetrad.
A Tetrad of Shoes • Two pairs of shoes = one tetrad • Each pair of shoes = one chromosome. • Each pair = sister chromatids • Each individual shoe = one chromatid.
Meiosis -- Preview • Occurs in two stages. • Steps are very similar to mitosis. • 4 haploid cells are end product of meiosis II. • Meiosis I and Meiosis II are similar. • Exceptions: • DNA replication Does NOT occur in Meiosis II. • TWO cells produced after Meiosis I and FOUR cells after Meiosis II.
From Diploid to Haploid • Meiosis I – results in TWO cells b/c TETRAD has been separated. • Genetic information is “swapped” between maternal and paternal chromatids. This is called synapse.
From Diploid to Haploid • Meiosis II – results in FOURcells b/c sister chromatidshave been separated. • New cell are genetically differentdue to cross over.
Meiosis—Party Time! SQUARE DANCING!!
Turkey in the CELL SQUARE DANCE MOVES/TERMS Link arms – represents the centromere Synapse – bump hips “crossing over” Mosey – a cross between a skip and a gallop Metaphase plate – the equator of the cell (it is the middle of the room) Salute – wave and bow
Meiosis I – The Nitty Gritty • Prophase I – chromatin condense into chromosomes, tetrads form, spindles form • Metaphase I -- tetrads line up at the equator, spindles attach to centromere • Anaphase I – tetrads are pulled apart toward the poles by spindle fibers • Telophase I – cell splits completely producing two daughter cells with one complete chromosome (sister chromatids)
Meiosis II – The Scoop • Meiosis II – Repeats the steps as Meiosis I with HALF as many chromosomes • Prophase II – DNA does NOT replicate. • Metaphase II–Sister Chromatidsline up at the equator. • Anaphase II – Sister chromatidsare pulled toward the poles and separate. • Telophase II – Cell splits 4 haploid cells are formed, with 1 chromatid.
Thank You!! Ya’ll come back now! I hope you enjoyed the show and learned something.
Bibliography • Beyonce http://www.zimbio.com/picture/lihk6AfVkBL/Beyonce+Knowles • Homologous Chromosomes http://www.kdimages.com/discover/previews/916/90011467.JPG • Chromatin http://www.micro.magnet.fsu.edu/cells/nucleus/images/chromatinstructuresfigure1.jpg • Chromatid http://www.wpcontent.answcdn.com/wikipedia/commons/thumb/0/0b/chromosomes.ssvg/220px-Chromosome.sv • Tetrad http://www.synapses.co.uk/genetics/meiosis.html • Meiosis Phases http://1.bp.blogspot.com/-bRrXTfFkHTE/S1zINGEyw-I/AAAAAAACs/epEwg1sD.jpg • Meiosis vs Mitosis http://image.wistatutor.com/content/fundamental-unit-life/meiosis-and-mitosis-cell-division.jpeg • Meiosis Stain www.brown.edu/Courses/BIoo32/gentherp/meiosis.jpg • Waving Hands http://1.thumbs.canstock.com/canstock0046569.jpg