KEY CONCEPT A cell’s life consists of a repeating pattern of events called the cell cycle.

Cell Cycle Events include: Growth Carrying out is job DNA and organelle duplication Division

The Cell Cycle is divided into two main stages: Interphase and Cell Division .

INTERPHASE Purpose: Grow, Carry out Job, Prepare for Cell Division G1 - Cell growth, Do job Duplicate organelles S - DNA synthesis (copies DNA) G2 - Additional growth, Duplicate organelles Normal functions

2 Parts of Cell Division “M” Stage: 1. Mitosis 2. Cytokinesis

MITOSIS “Nuclear Divison” Purpose: Divides nucleus into 2 genetically identical nuclei 4 Stages of Mitosis: Prophase Metaphase Anaphase Telophase

CYTOKINESIS PURPOSE: Divide the cytoplasm to form two separate cells Animal Cell Plant Cell

The Final Product of the Cell Cycle…… 2 Daughter Cells that are genetically identical to the parent cell – same # of chromosomes with same DNA information         Start of Interphase End of Interphase/ End of Mitosis Beginning of Mitosis End of Cytokinesis

Reasons Cells Divide Growth Replacement Repair Maintain size limit (surface area to volume ratio)

Cell size is limited. Volume increases faster than surface area.

Cells divide at different rates. The rate of cell division varies with the need for those types of cells. Some cells are unlikely to divide (G0) Ex. Neurons (nerves).