The CELL CYCLE AND MITOSIS!

Interphase Longest stage in the cell cycle The stage in which cells carry out the functions necessary for survival: Growth and preparation DNA replication Continued growth and replication

Mitosis Usually the shortest stage The stage in which the contents of the cell’s nucleus divides into two equal parts The phases of mitosis: Prophase Metaphase Anaphase Telophase

Prophase Chromosomes condense Spindle fibres form Chromosomes attach to the spindle fibres at their centromeres Nucleolus and nuclear membrane disappear

Metaphase Spindle fibres pull the X-shaped chromosomes into a single line across the middle of the cell (equator)

Anaphase Spindle fibres begin to contract and shorten Centromere pulls apart Chromosomes move to opposite poles of the cell

Telophase One complete set of chromosomes is at each pole of the cell Spindle fibres begin to disappear Nuclear membrane and nucleolus forms in each cell Cell is ready to divide

Cytokinesis Seperates the two nuclei and cell contents into two daughter cells.

Checkpoints in the Cell Cycle Cells will not divide: Not enough nutrients DNA has not replicated DNA is damaged

Cancer If a mutation occurs in the checkpoint protein gene, cell cycle control will be lost. A damaged cell may divide uncontrollably. Cancer is the result of uncontrolled cell growth. How cancer grows