1. The Cell Cycle & Cell Division

2. Cells have a life cycle Cells develop and grow
Somatic cells (body cells) of a multicellular organism perform specialized functions to keep the organism functioning
Life cycle of a cell is called the Cell Cycle
Interphase
Mitosis

3. The Cell Cycle

4. The Cell Cycle The sequence of growth and division of a cell.
~95% of cell cycle in interphase
Time when cell carries out its function
~5% of cell cycle in mitosis
Cell divides

5. Interphase The cell prepares for division
Cell carries out its “life” functions
Maintains homeostasis and carries out metabolic reactions
DNA replicated
Organelles replicated
Cell increases in size

6. Chromosomes Homologous Chromosomes Sister chromatids Centromere
Pair of chromosomes that have the same types of genes on them in the same locations
Sister chromatids
A duplicated chromosome
Created after DNA replication
Centromere
Holds sister chromatids together after DNA replication

7. Chromosomes
Before replication = 2 copies of each chromosome (homologous pair)
After replication = 4 copies of each chromosome (sister chromatids within a homologous pair)

8. Cell Division: Mitosis
Cells leave interphase and enter mitosis to…
Maintain size
Growth and repair
Asexual reproduce (unicellular organisms)

9. Mitosis can be divided into stages
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis

10. Prophase The cell prepares for nuclear division
DNA condenses into chromosomes
Nuclear membrane disappears

11. Metaphase Chromosomes line up on the metaphase plate
Chromosomes line up at the center of the cell
Spindle fibers attach to the chromosomes at the centromere

12. Anaphase The chromosomes divide and separate
Spindle fibers pull chromosomes apart by separating the sister chromatids of each homologous pair

13. Telophase The Nuclei Return
Chromosomes begin to uncoil
Nuclear membranes begin to form

14. Cytokinesis The cytoplasm divides
Cytoplasm divides and separates
Cleavage furrow pinches cell membrane between the two new nuclei
Happens at the same time as telophase
2 identical daughter cells are formed