Centromere and independent assortment occurs which is

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centromere and independent assortment occurs (which is random alignment of chromosomes) Anaphase 1: homologous chromosomes separate and move to opposite poles of cell and sister chromatids are still together (centromere doesn’t split so two sister chromatids from each homologous pair moves to each pole of cell -chromosome number is reduced from 2n (diploid) to n (haploid) Telophase1:homologous chromosomes begin to uncoil -spindle fibres disappear -cytokinesis happens forming nucleur membrane around each group of homologous chromosomes, two cells form (technically they’re haploid b/c they have 46 chromatids but 23 chromosomes) *No replication between Meiosis and Meiosis 2 MEIOSIS 2 (similar to mitosis) Prophase 2: centrosomes duplicate, nuclear membrane disappears, spindle fibres form Metaphase 2: haploid number of chromosomes lie up at the equator and spindle fibres attach to kinetocores on centromeres -2 chromosomes in each, 2 new haploid cells Anaphase 2: sister chromatids pulled apart at centromers by spindle fibers (happening in both new haploid cells) -now starts to form 4 new haploid cells (each haploid cell has 2 sister chromatids forming one chromosome) Telephase 2: nuclear membrane forms around 4 new haploid cells each with half number of chromosomes from the parent cell synapsis the aligning of homologous chromosomes during prophase 1 homologous chromosomes chromosomes that contain the same sequence of genes as another chromosome
What creates genetic diversity? Prophase 1-crossing over and Metaphase 1-independent assortment Oogenesis: the process of producing female gametes (eggs) in mammals and starts with ovam (female gamete, plural ova) Oogonia reproduce by mitosis after birth, begin meiosis 1 but stop at prophase 1, and at puberty meiosis 1 will continue to release one cell each month Process: -Start with diploid oogonium (oogonia) undergo mitosis before birth -Remaining oogonia that don’t die undergo meiosis and become primary oocytes -Primary oocytes pause during prophase 1 after replicating but before meiois 1 they stay rested until their menstrual cycles begin -When girl hit puberty p.o resume meiois from where they left off and finish meiois 1, (they stop at metaphase 2 unless they are fertilized) then divides chromosomes equally but there is unequal division of cytoplasm -At cytokinesis almost all cytoplasm remains in one of the two daughter cells which becomes the secondary oocyte -The other daughter cell with half the chromosomes but little cytoplasm is called polar body and since its not functional it’ll eventually degenerate and die -S.o (has 2 copies of each chromosome) and become a fully functional ovum must undergo meosis 2 and division in uneven again (where half chromosome going to small degenerate polar bear) -The other half is gone to the ovum (half chromosome and almost all of cytoplasm) creating an egg
Spermatogenesis: the process of producing male gametes (sperm) in mammals-doesn’t start until puberty Process: -Starts with diploid cell called spermatogonium (plural spermatogonia)

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