Reproduction 2 Types If both parents replicated cells using mitosis a child would receive 46 chromosomes from dad amp 46 from mom given a grand total of 92 Way too many Soif dad could give 23 23 from mom 46 Bingo ID: 770765
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Reproduction!!! 2 Types
If both parents replicated cells using mitosis, a child would receive 46 chromosomes from dad & 46 from mom given a grand total of…? 92! (Way too many) So…if dad could give 23 + 23 from mom = 46! (Bingo !)
Examples of Asexua l!!!! Binary Fission Budding Fragmentation
Better when the environment is not favorable or becomes unstable
Meiosis
Meiosis Def: 2 successive cell divisions that produce gametes What does that mean? Successive one right after the otherGametes a haploid reproductive cell, either an egg or a sperm Haploid containing only 1 of every chromosomes (n)Diploid containing 2 of every chromosome (2n)
Some More Vocabulary Body Cells AKA somatic cells Ex skins cells, nerve cells, blood cells Diploid 46 chromosomes (23 pairs ) Sex Cells AKA germ cells Ex egg & spermHaploid 23 chromosomes (all single ) Q: A mutation in which type of cell would be worse?
Chromosome Number in Mitosis
Meiosis = 2 Mitosis P 1 M 1 A 1 T1 P2M2 A2T2 With a few slight differences!
Prophase I Metaphase I Anaphase I Telophase I Meiosis = 1 st Division Prophase 1 Crossing Over Metaphase 1 chromosomes line up randomly 2 by 2 forming a tetrad (4 across) Anaphase 1 homologous chromosomes are pulled to opposite poles ( sister chromatids do not separate!)
Crossing Over
Single Chromosomes line up Sister Chromatids are pulled apart Prophase 2 Metaphase 2 Anaphase 2 Telophase 2 Meiosis II 2nd Division
Mitosis vs. Meiosis Cells divide twice ! (Mitosis divide only once) End result is 4 different cells instead of 2 genetically identical cells! Chromosome number is cut in half! 2n (diploid) n (haploid) = Meiosis 2n 2n = MitosisCrossing Over!
The purpose of meiosis is…? To produce gametes which are necessary for sexual reproduction.Allows for new mixtures of combinations called genetic recombination VARIATION!