The Cell Cycle Period of time from the beginning of 1 division to the next Some cells stop dividing after full development of an organism Heart; Brain Some cells are constantly dividing Skin; intestines Time for the cell cycle: 3o minutes to 2o hours in humans

The Cell Cycle - Interphase Period of time where cell performs “normal” activities except reproduction Inter = between; “resting phase” Cell spends most time in Interphase DNA & proteins seen as chromatin DNA controls cell activities Can be split into 3 phases: G1: Cell grows; does normal activities S: Synthesizes chromatin (amount is doubled) and organelles G2: Cell grows more; normal activities; prepares for mitosis

The Cell Cycle - Mitosis Nuclear division of the cell (dividing the nucleus) Can be split into 4 phases: PMAT Prophase: DNA condensed into chromosomes; nuclear envelope starts to breakdown Metaphase: centromeres line up at the equator of the cell Anaphase: chromosomes pulled apart to poles Telophase: nuclear envelope reforms; chromosomes at the poles

The Cell Cycle - Cytokinesis Division of the cytoplasm Forms 2 identical daughter cells In animal cells: cell membrane is pinched, making 2 cells with a complete set of chromosomes Pinched area is called a Cleavage Furrow In plant cells: vesicles create a line across the cell in the middle of the 2 nuclei This line is the Cell Plate

Mitosis Pictures Project Key: Centrioles Chromatin Chromosomes Spindle Fibers

Mitosis Pictures Project: Interphase G1 Interphase S-G2