Meiosis I Meiosis I results in 2 haploid

Meiosis I • Meiosis I results in 2 haploid daughter cells

Meiosis II Meiosis • Each of the haploid daughter cells from meiosis I divide again to make 4 haploid cells.

Comparing Mitosis and Meiosis • The processes of mitosis and meiosis are very similar, but with some important differences: Mitosis l l l Includes only 1 cycle of cell division Occurs in body cells (somatic cells) No crossing over of chromosomes Results in two genetically identical diploid cells Metaphase: 1 duplicated chromosome per spindle fiber Meiosis l l l Includes 2 cycles of cell division (meiosis I and meiosis II) Occurs only in sex cells (gametes) Chromosomes cross over in Prophase I Results in four genetically different haploid cells Metaphase I: 2 duplicated chromosomes per spindle fiber

Interphase • DNA replication occurs • DNA is in chromatin form (unwound, like spaghetti)

Prophase I • DNA condenses to form chromosomes • Homologous chromosomes pair up to form tetrads • Crossing over takes place

Metaphase I • Homologous pairs line up along center of cell • 1 homologous chromosome and its duplicate are attached to each spindle fiber

Anaphase I • Homologous pairs separate, move to opposite ends of the cell

Telophase I • Nuclear membrane reappears • Spindle fibers disappear

Cytokinesis • Cytoplasm of the two cells separate • Meiosis I results in 2 haploid cells that are genetically different

Prophase II • The 2 haploid cells from Meiosis I will divide again

Metaphase II • Chromosomes (set of sister chromatids) line up along the center of the cell • 1 sister chromatid attaches to each spindle fiber

Anaphase II • Centromeres split, sister chromatids are pulled apart

Telophase II and Cytokinesis • Cytoplasm divides, resulting in 4 genetically different haploid cells