5.2 Mitosis and Cytokinesis

Cells divide during mitosis

5.2 Mitosis and Cytokinesis

During Mitosis, the DNA is coiled to prevent it from being tangled. We call the coiled DNA chromosomes. After mitosis, it uncoils so that it may be used by the cell.

DNA double

helixDNA andhistones

Chromatin SupercoiledDNA

5.2 Mitosis and Cytokinesis

• One half of a duplicated chromosome is a chromatid.

• Duplicate copies are called Sister chromatids. They are held together at the centromere.

• Telomeres are at the ends of the chromosomes. They protect DNA and do not include genes.

Condensed, duplicated chromosome

chromatid

telomere

centromere

telomere

Sister Chromatids

5.2 Mitosis and Cytokinesis

Parent cell

centrioles

spindle fibers

centrosome

nucleus withDNA

Interphase

Not a phase of Mitosis.

• Includes G1, S, G2

• DNA is checked for mistakes, duplicated, & checked again.

• Normal cell activity-life!• Interphase prepares

the cell for Cell division

nucleus

5.2 Mitosis and Cytokinesis

Prophase—Wind Up!

• Chromosomes condense • Spindle fibers form, Centrioles move to poles• Membrane around nucleus begins to dissolve

5.2 Mitosis and Cytokinesis

Metaphase—Line Up!

• chromosomes line up in the middle of the cell• Spindle Fibers attach to Centromere.• point are spindle fibers attached???

Centromere

Spindle fiber

Centriole

5.2 Mitosis and Cytokinesis

Anaphase-Separate!

• sister chromatids are pulled apart by the spindle fibers.

5.2 Mitosis and Cytokinesis

Telophase--Divide• Nucleus begins to form in each cell • chromosomes begin to uncoil

5.2 Mitosis and Cytokinesis

Cytokinesis

• Cytoplasm and organelles are divided between 2 daughter cells.

• DNA is uncoiled• In animal cells, the

membrane pinches closed.

• In plant cells, a cell plate forms (new cell wall) between the cells.