Division in meiosis I and II Division in meiosis I occurs in four phases: – Prophase I\ – Metaphase I – Anaphase I – Telophase I and cytokinesis Division in meiosis II occurs in four phases: – Prophase II – Metaphase II – Anaphase II – Telophase II and cytokinesis

Figure 13.7 Overview of meiosis: how meiosis reduces chromosome number Interphase Homologous pair of chromosomes in diploid parent cell Chromosomes replicate Homologous pair of replicated chromosomes Sister chromatids Diploid cell with replicated chromosomes Meiosis I Figure 13.7 Overview of meiosis: how meiosis reduces chromosome number 1 Homologous chromosomes separate Haploid cells with replicated chromosomes 2

Figure 13.7 Overview of meiosis: how meiosis reduces chromosome number Interphase Homologous pair of chromosomes in diploid parent cell Chromosomes replicate Homologous pair of replicated chromosomes Sister chromatids Diploid cell with replicated chromosomes Meiosis I Figure 13.7 Overview of meiosis: how meiosis reduces chromosome number 1 Homologous chromosomes separate Haploid cells with replicated chromosomes Meiosis II 2 Sister chromatids separate Haploid cells with unreplicated chromosomes 3

Figure 13.8 The meiotic division of an animal cell Prophase I Metaphase I Anaphase I Telophase I and Cytokinesis Prophase II Metaphase II Anaphase II Telophase II and Cytokinesis Centrosome (with centriole pair) Sister chromatids remain attached Centromere (with kinetochore) Sister chromatids Chiasmata Spindle Metaphase plate Sister chromatids separate Haploid daughter cells forming Homologous chromosomes Homologous chromosomes separate Cleavage furrow Fragments of nuclear envelope Microtubule attached to kinetochore Figure 13.8 The meiotic division of an animal cell 4

Prophase I Metaphase I Anaphase I Centrosome (with centriole pair) Fig. 13-8a Telophase I and Cytokinesis Prophase I Metaphase I Anaphase I Centrosome (with centriole pair) Sister chromatids remain attached Centromere (with kinetochore) Sister chromatids Chiasmata Spindle Metaphase plate Figure 13.8 The meiotic division of an animal cell Cleavage furrow Homologous chromosomes Homologous chromosomes separate Fragments of nuclear envelope Microtubule attached to kinetochore 5

Telophase II and Cytokinesis Fig. 13-8d Telophase II and Cytokinesis Prophase II Metaphase II Anaphase II Sister chromatids separate Haploid daughter cells forming Figure 13.8 The meiotic division of an animal cell 6