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Introduction to Botany. Lecture 22 Questions and answers Mitosis, syngamy and meiosis Life cycles Introduction to Botany. Lecture 22 Alexey Shipunov Minot State University October 21, 2011 Shipunov BIOL 154.22 Questions and answers Mitosis, syngamy and meiosis Life cycles Outline 1 Questions and answers 2 Mitosis, syngamy and meiosis Syngamy 3 Life cycles General life cycle Shipunov BIOL 154.22 Questions and answers Mitosis, syngamy and meiosis Life cycles Outline 1 Questions and answers 2 Mitosis, syngamy and meiosis Syngamy 3 Life cycles General life cycle Shipunov BIOL 154.22 Questions and answers Mitosis, syngamy and meiosis Life cycles Outline 1 Questions and answers 2 Mitosis, syngamy and meiosis Syngamy 3 Life cycles General life cycle Shipunov BIOL 154.22 Segregation of homologs (which have being crossed over in metaphase I) versus pulling apart chromatids Questions and answers Mitosis, syngamy and meiosis Life cycles Previous final question: the answer What is the difference between anaphase I of meiosis and anaphase of mitosis? Shipunov BIOL 154.22 Questions and answers Mitosis, syngamy and meiosis Life cycles Previous final question: the answer What is the difference between anaphase I of meiosis and anaphase of mitosis? Segregation of homologs (which have being crossed over in metaphase I) versus pulling apart chromatids Shipunov BIOL 154.22 Questions and answers Mitosis, syngamy and meiosis Life cycles Unusual meiosis of evening primrose, Oenothera Shipunov BIOL 154.22 Questions and answers Mitosis, syngamy and meiosis Syngamy Life cycles Mitosis, syngamy and meiosis Syngamy Shipunov BIOL 154.22 Questions and answers Mitosis, syngamy and meiosis Syngamy Life cycles Definition of syngamy Fusion of two cells, where resulted cell will have two times more chromosomes Initial cells are gametes, resulted cell is a zygote Chromosome formula: X + X −! XX The goal of syngamy is the renovation of genetic material Syngamy changes genotype of cells Shipunov BIOL 154.22 Questions and answers Mitosis, syngamy and meiosis Syngamy Life cycles Types of syngamy (Y!) Shipunov BIOL 154.22 Questions and answers Mitosis, syngamy and meiosis Syngamy Life cycles Polyploids If for some reason, meiosis will not run correctly, one of resulted cells could receive double set of chromosomes (2n instead of n) If this cell goes to syngamy, resulted zygote will have 3n chromosomes Cells with > 2n chromosomes are polyploids Shipunov BIOL 154.22 Questions and answers Mitosis, syngamy and meiosis General life cycle Life cycles Life cycles General life cycle Shipunov BIOL 154.22 Questions and answers Mitosis, syngamy and meiosis General life cycle Life cycles Simple and general life cycles Terms covered: Mitosis, meiosis, syngamy Haplont, diplont, haploid, diploid Gamete mother cell, gametangium, gametes, male, female, spermatozoon, spermatium, oocyte Syngamy, isogamy, heterogamy, oogamy, zygote Spore mother cell, sporangium, spore Sexual reproduction, asexual reproduction, vegetative reproduction Shipunov BIOL 154.22 Questions and answers Mitosis, syngamy and meiosis General life cycle Life cycles Simple life cycle Shipunov BIOL 154.22 Questions and answers Mitosis, syngamy and meiosis General life cycle Life cycles General life cycle Shipunov BIOL 154.22 Why sexes arose in the evolutionary process? Questions and answers Mitosis, syngamy and meiosis General life cycle Life cycles Final question (2 points) Shipunov BIOL 154.22 Questions and answers Mitosis, syngamy and meiosis General life cycle Life cycles Final question (2 points) Why sexes arose in the evolutionary process? Shipunov BIOL 154.22 Questions and answers Mitosis, syngamy and meiosis General life cycle Life cycles For Further Reading J. E. Bidlack, Sh. H. Jansky. Stern’s introductory plant biology. 12th edition. McGraw-Hill, 2011. Chapter 12. Th. L. Rost, M. G. Barbour, C. R. Stocking, T. M. Murphy. Plant Biology. 2nd edition. Thomson Brooks/Cole, 2006. Chapter 12 (skip angiosperm life cycle!). Shipunov BIOL 154.22.
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