5 2 Mitosis and Cytokinesis KEY CONCEPT Cells

5. 2 Mitosis and Cytokinesis KEY CONCEPT Cells divide during mitosis and cytokinesis.

5. 2 Mitosis and Cytokinesis Chromosomes condense at the start of mitosis. • • • A chromosome is one long continuous thread of DNA wraps around proteins (histones) that condense it. DNA and histones form chromatin. Sister chromatids are held together at the centromere. One half of a duplicated chromosome is a chromatid. DNA double helix DNA and histones Chroma tin Supercoiled DNA

5. 2 Mitosis and Cytokinesis chromatid • Telomeres protect DNA and do not include genes. telomere centromere telomere Condensed, duplicated chromosome

5. 2 Mitosis and Cytokinesis Mitosis and cytokinesis produce two genetically identical daughter cells. Parent cell • Interphase prepares the cell to divide. • During interphase, the DNA is duplicated • The cell grows • Organelles duplicate. centrioles spindle fibers centrosome nucleus with DNA

5. 2 Mitosis and Cytokinesis • Mitosis divides the cell’s nucleus in four phases. – During prophase, chromosomes condense and spindle fibers form.

5. 2 Mitosis and Cytokinesis • Mitosis divides the cell’s nucleus in four phases. – During metaphase, chromosomes line up in the middle of the cell.

5. 2 Mitosis and Cytokinesis • Mitosis divides the cell’s nucleus in four phases. – During anaphase, sister chromatids separate to opposite sides of the cell. Cytokinesis begins.

5. 2 Mitosis and Cytokinesis • Mitosis divides the cell’s nucleus in four phases. – During telophase, the new nuclei form and chromosomes begin to uncoil.

5. 2 Mitosis and Cytokinesis • Cytokinesis divides the cytoplasm into 2 daughter cells. • Cytokinesis differs in animal and plant cells. – In animal cells, the membrane pinches closed. – In plant cells, a cell plate forms.

5. 2 Mitosis and Cytokinesis • http: //www. youtube. com/watch? v=Q 6 uc. KWIIFmg