Mitosis Stages

Meiosis I

• Centrosomes with centriole pairs are present during interphase I
• Chiasmata and spindle formation occur in prophase I
• Microtubules attach to kinetochore during metaphase I, and chromosomes line up at the metaphase plate
• Sister chromatids remain attached during anaphase I
• Nuclear envelope and chromatin reform, and chromosomes duplicate during anaphase I
• Tetrad formation occurs through synapsis, where homologous chromosomes pair and exchange segments, and then separate
• Centromere has a kinetochore, and tetrads line up at the metaphase plate

Meiosis II

• Cells go from diploid to haploid during meiosis II
• Prophase II, metaphase II, anaphase II, and telophase II occur
• Two haploid cells form, with chromosomes still being double
• Sister chromatids finally separate during another round of cell division, resulting in four haploid daughter cells with single chromosomes
• Cleavage furrow forms during cytokinesis in animal cells
• Sister chromatids separate and haploid daughter cells form

Mitosis

Stages of Mitosis

• Prophase: Chromosomes condense and become visible, spindle fibers emerge from centrosomes, nuclear envelope breaks down, and nucleolus disappears
• Prometaphase: Chromosomes continue to condense, kinetochores appear at centromeres, mitotic spindles microtubules attach to kinetochores, and centrosomes move toward opposite poles
• Metaphase: Mitotic spindle is fully developed, centrosomes are at opposite poles, chromosomes are lined up at the metaphase plate, and each sister chromatid is attached to a spindle fiber originating from opposite poles
• Anaphase: Cohesion proteins binding sister chromatids break down, sister chromatids are pulled toward opposite poles, and non-kinetochore spindle fibers lengthen, elongating the cell
• Telophase: Chromosomes arrive at opposite poles, begin to decondense, nuclear envelope material surrounds each set of chromosomes, and the mitotic spindle breaks down
• Cytokinesis: Animal cells have a cleavage furrow separating daughter cells, while plant cells have a cell plate separating daughter cells