The Cell Cycle 4 phases exist in the cell cycle for somatic (body) cells. – During cell reproduction the chromatin will condense into chromosomes. We have 22 pairs of somatic chromosomes and 2 sex chromosomes (46 total). – cells copy their DNA via mitosis All of the DNA copied is part of the organism's genome and are made of long strands named chromatin. – divide via cytokinesis to form daughter cells that are identical to the parent. After the cell has successfully replicated its chromosomes it undergoes cytokinesis (cell division) and the cleavage furrow (invagination of the surface of the cell) to form 2 identical cells.

Cell Cycle - Interphase G1 - cell is replicating proteins necessary for replication of DNA and cell division. – Signals cell death (apoptosis) if errors are found. – interphase begins S - DNA is replicated (synthesized) G2 - cell continues to grow and DNA is checked for errors and arranged. – 2 centrosomes have formed from one centrosome each centrosome consists of 2 centrioles – chromatin is still non-condensed – interphase is ended

M-Phase Prophase – Metaphase – Anaphase – Telophase Prophase – chromatin begins to tightly coil – nuclear envelope begins to disappear – nucleoli disappear – each chromosome is now a complex of sister chromatids – mitotic spindle begins to form – centrosomes move away fro each other Prometaphase – nuclear envelope fragments – microtubules move through the nuclear area through the center of the cell – each sister chromatid complex is now connected to a microtubules by the kinetochore region

M-Phase Metaphase – longest phase – centrosomes are now at opposite sides of the cell – chromosomes are located at the metaphase plate (center) – kinetochores of the sister chromatids are now attached to tubules of opposite centrosomes – microtubule complex is now called the spindle

M-Phase Anaphase – shortest phase – sister chromatids are pulled apart as the spindle fibers shorten – the separated chromosomes migrate toward the opposite poles – at the end of anaphase the polar regions of the cell have equivalent amounts and types of chromosomes Telophase – the 2 daughter cell nuclei begin to form – nuclear envelopes begin to form from the parent fragments – chromosomes become less condensed – mitosis is complete with the completion of the 2 nuclei regions Cytokinesis – the cell divides at the cleavage furrow shortly after Mitosis