Presentation on theme: "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."— Presentation transcript:
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) A series of steps similar to mitosis. B) Haploid cells (gametes). C) A lot of vowels. D) Both A and B are correct.
What is a haploid cell? A) A cell that is happy. B) A sex cellegg or sperm. C) A cell that has half the number of chromosomes as a somatic (body) cell. D) 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 stagesMeiosis I and Meiosis II. Meiosis I – separates the tetrad resulting in TWO cells. Meiosis II – separates the sister chromatids resulting FOUR cells.
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 1) Chromatid 2) Centromere 3) Short-Arm of chromatid 4) 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 FOUR cells b/c sister chromatids have been separated. New cell are genetically different due to cross over.
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 Chromatids line up at the equator. Anaphase II – Sister chromatids are pulled toward the poles and separate. Telophase II – Cell splits 4 haploid cells are formed, with 1 chromatid.