The Cell Cycle & Cell Division

The Cell Cycle Most cells in an organism go through a cycle of growth, development, and division called the cell cycle. The cell cycle allows organisms : to grow and develop replace old or damaged cells produce new cells.

Phases Of The Cell Cycle There are two main phases of the cell cycle: Interphase Mitotic phase

Interphase Interphase is a period of growth and development for a cell. It makes up most of the cell cycle During interphase, The DNA of the cell is called chromatin

Interphase During interphase, cells go through three stages: 1. Rapid growth and replication of the organelles. (G1 stage)

Interphase 2. Replication of DNA . (S stage) The cell replicates its strands of chromatin Sister chromatids are the two identical strands of DNA that make up the duplicated chromosome. They are held together by a structure called a centromere.

Interphase 3. Growth and final preparation for cell division (G2 Stage

Mitotic Phase Mitosis- The process of cell division that results in 2 identical cells(daughter cells) with the same number of chromosomes. Only happens in body cells Sub-stages of Mitosis: Prophase Metaphase Anaphase Telophase Cytokinesis

Prophase Duplicated DNA condenses into chromosomes

Metaphase Chromosomes line up in the middle of the cell

Anaphase Sister chromatids in each duplicated chromosome separate and are pulled in opposite directions by the spindle fibers

Telophase Chromosomes begin to uncoil, and 2 new identical nuclei form

Cytokinesis Cytokinesis divides a cell’s cytoplasm forming a new cell membrane around each daughter cell. In animal cells , a furrow in the middle of the cell gets deeper until the cell membrane comes together to divide the cell.

Cytokinesis In plants, a cell plate grows outward toward a new cell wall until 2 new cells form

The cell cycle is important for : for reproduction in some organisms growth in multi-cellular organisms replacement of worn-out or damaged cells Repair of damaged tissues