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Meiosis

Meiosis. Figure 13.2. 0.5 mm. Parent. Bud. (b) Redwoods. (a) Hydra. Figure 12.7a. Prometaphase. G 2 of Interphase. Prophase. Fragments of nuclear envelope. Centrosomes (with centriole pairs). Early mitotic spindle. Nonkinetochore microtubules. Chromatin (duplicated). Aster.

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Meiosis

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  1. Meiosis

  2. Figure 13.2 0.5 mm Parent Bud (b) Redwoods (a) Hydra

  3. Figure 12.7a Prometaphase G2 of Interphase Prophase Fragments of nuclearenvelope Centrosomes(with centriole pairs) Early mitoticspindle Nonkinetochoremicrotubules Chromatin(duplicated) Aster Centromere Plasmamembrane Kinetochore Nucleolus Kinetochoremicrotubule Chromosome, consistingof two sister chromatids Nuclearenvelope

  4. Figure 12.7b Metaphase Anaphase Telophase and Cytokinesis Nucleolusforming Metaphase plate Cleavagefurrow Nuclearenvelopeforming Spindle Centrosome atone spindle pole Daughterchromosomes

  5. Figure 13.3a

  6. Figure 13.3b 5 m Pair of homologousduplicated chromosomes Centromere Sisterchromatids Metaphasechromosome

  7. Figure 13.3c 5 m

  8. Figure 13.4 Key Key Maternal set ofchromosomes (n 3) 2n 6 Paternal set ofchromosomes (n 3) Sister chromatidsof one duplicatedchromosome Centromere Two nonsisterchromatids ina homologous pair Pair of homologouschromosomes (one from each set)

  9. Key Haploid (n) Figure 13.6a Diploid (2n) Gametes n n n MEIOSIS FERTILIZATION Zygote 2n 2n Diploidmulticellularorganism Mitosis (a) Animals

  10. Key Haploid (n) Figure 13.6b Diploid (2n) Haploid multi-cellular organism(gametophyte) Mitosis Mitosis n n n n n Spores Gametes MEIOSIS FERTILIZATION 2n 2n Diploidmulticellularorganism(sporophyte) Zygote Mitosis (b) Plants and some algae

  11. Key Haploid (n) Figure 13.6c Diploid (2n) Haploid unicellular ormulticellular organism Mitosis n Mitosis n n n n Gametes MEIOSIS FERTILIZATION 2n Zygote (c) Most fungi and some protists

  12. Figure 13.6 Key Haploid (n) Haploid unicellular ormulticellular organism Haploid multi-cellular organism(gametophyte) Diploid (2n) Gametes n n Mitosis Mitosis Mitosis Mitosis n n n n n n n n Spores n MEIOSIS FERTILIZATION n Gametes n Gametes MEIOSIS FERTILIZATION FERTILIZATION MEIOSIS Zygote 2n 2n 2n 2n Diploidmulticellularorganism(sporophyte) Zygote 2n Diploidmulticellularorganism Mitosis Mitosis Zygote (a) Animals (b) Plants and some algae (c) Most fungi and some protists

  13. 2 1 Interphase Figure 13.7-3 Pair of homologouschromosomes indiploid parent cell Chromosomesduplicate Duplicated pairof homologouschromosomes Sisterchromatids Diploid cell withduplicatedchromosomes Meiosis I Homologouschromosomes separate Haploid cells withduplicated chromosomes Meiosis II Sister chromatidsseparate Haploid cells with unduplicated chromosomes

  14. Figure 13.8a Telophase I andCytokinesis Anaphase I Metaphase I Prophase I Centrosome(with centriole pair) Sister chromatidsremain attached Chiasmata Sisterchromatids Centromere(with kinetochore) Spindle Metaphaseplate Cleavagefurrow Homologouschromosomesseparate Fragmentsof nuclearenvelope Homologouschromosomes Microtubuleattached tokinetochore Each pair of homologous chromosomes separates. Two haploid cells form; each chromosomestill consists of two sister chromatids. Chromosomes line upby homologous pairs. Duplicated homologouschromosomes (red and blue)pair and exchange segments;2n 6 in this example.

  15. Figure 13.8b Telophase II andCytokinesis Metaphase II Prophase II Anaphase II During another round of cell division, the sister chromatids finally separate;four haploid daughter cells result, containing unduplicated chromosomes. Haploid daughtercells forming Sister chromatidsseparate

  16. Human gametogenesis Oogenesis Spermatogenesis Figure 46.UN01 Primaryspermatocyte Primaryoocyte 2n 2n Polar body n Secondaryspermatocytes Secondaryoocyte n n n Spermatids n n n n Sperm n n n n Polar body n Fertilized egg n

  17. MEIOSIS MITOSIS Figure 13.9a Parent cell MEIOSIS I Chiasma Prophase Prophase I Chromosomeduplication Chromosomeduplication Duplicatedchromosome Homologouschromosome pair 2n 6 Metaphase I Metaphase Anaphase I TelophaseI AnaphaseTelophase Daughter cells ofmeiosis I Haploidn 3 MEIOSIS II 2n 2n Daughter cellsof mitosis n n n n Daughter cells of meiosis II

  18. Figure 13.9b SUMMARY Property Mitosis Meiosis DNAreplication Number ofdivisions Synapsis ofhomologouschromosomes Number of daughter cellsand geneticcomposition Role in the animal body

  19. Figure 13.10-1 Possibility 2 Possibility 1 Two equally probablearrangements ofchromosomes atmetaphase I

  20. Figure 13.10-2 Possibility 2 Possibility 1 Two equally probablearrangements ofchromosomes atmetaphase I Metaphase II

  21. Figure 13.10-3 Possibility 2 Possibility 1 Two equally probablearrangements ofchromosomes atmetaphase I Metaphase II Daughtercells Combination 1 Combination 2 Combination 3 Combination 4

  22. Prophase Iof meiosis Nonsister chromatidsheld togetherduring synapsis Figure 13.11-1 Pair of homologs

  23. Prophase Iof meiosis Nonsister chromatidsheld togetherduring synapsis Figure 13.11-2 Pair of homologs Chiasma Centromere TEM

  24. Prophase Iof meiosis Nonsister chromatidsheld togetherduring synapsis Figure 13.11-3 Pair of homologs Chiasma Centromere TEM Anaphase I

  25. Prophase Iof meiosis Nonsister chromatidsheld togetherduring synapsis Figure 13.11-4 Pair of homologs Chiasma Centromere TEM Anaphase I Anaphase II

  26. Prophase Iof meiosis Nonsister chromatidsheld togetherduring synapsis Figure 13.11-5 Pair of homologs Chiasma Centromere TEM Anaphase I Anaphase II Daughtercells Recombinant chromosomes

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