How Cells Divide Chapter 10

Cell Cycle “The sequence of growth and division in a cell”. There are two periods in the cell cycle: Interphase Mitosis

Eukaryotic Cell Cycle Interphase G1 S G2 M (mitosis) C (cytokinesis) Subdivided into 5 phases C (cytokinesis) Separation of 2 new cells Interphase

Interphase

M phase Mitosis is divided into 5 phases: 1. Prophase 2. Prometaphase 4. Anaphase 5. Telophase

Prophase

Prometaphase

Metaphase

Anaphase

Telophase

C Y T O K I N E S s

Interphase Prophase Prometaphase Metaphase Anaphase Telophase

Mitosis Mitosis is responsible for the growth, development and repair of cells. Growth factors –”chemicals that stimulate the division and differentiation of cells”. Differentiation - when new cells take on special shapes or special functions (muscle cells)

Control of the Cell Cycle Current view integrates 2 concepts Cell cycle has two irreversible points Replication of genetic material Separation of the sister chromatids Cell cycle can be put on hold at specific points called checkpoints Process is checked for accuracy and can be halted if there are errors Allows cell to respond to internal and external signals

3 Checkpoints G1/S checkpoint G2/M checkpoint Late metaphase (spindle) checkpoint

Tumors Occur when the cells lose control of the cell cycle, allowing the cells to grow uncontrollably. Tumors - can be benign can be malignant

Cancer Cells that gain abnormal size, shape or abilities. Ability to break free from the original tumor and invade healthy tissues, turning them into cancer cells.