I. MITOSIS A. Cell Division: 1. Needed for normal growth, repair, & development 2. Occurs in somatic cells (body cells) 3. Daughter cells have an exact copy of DNA of parent cell 4. Each parent cell produces 2 daughter cells

B. Why Do Cells Divide? 1. Volume Limit: a) food intake b) waste removal 2. Volume to Surface Area Ratio -Volume increases much more rapidly than surface area as the cell grows in size Will do lab on Volume to Surface Area ratio. Cells can only take in food/get rid of waste at the surface of cells. If the volume to surface area ratio is too big, cells cannot take in enough food or get rid of all the waste. Pause to do examples with cube dimensions, SA, vol, ratio

II. Cell Cycle

A. Interphase 1. Not part of Mitosis 2. 90 % time here 3. Carries out metabolic processes: Making new molecules & organelles Normal growth/development Cell prepare for division 4. DNA replication 5. Chromosomes are not distinguishable (chromatin) 6. Prepares for cell division Chromosomes contain the DNA/genetic material. Called chromatin when not consolidated

1. G1 phase (normal growth) 2. S phase (synthesis) 7. Cell Cycle: 1. G1 phase (normal growth) 2. S phase (synthesis) 3. G2: prepares to divide 4. Mitosis/Cytokineses G1 and G2 the cell grows and functions normally DNA replicates in S phase

Mitosis Begins Cell Cycle Continues

B. Prophase 1. First stage of mitosis 2. Chromosomes appear (shorten & thicken = sister chromatids) 3. Centrioles, spindle fibers appear 4. Nuclear membrane dissolves Sister chromatids contain two copies of identical DNA (replicated during S phase)

C. Metaphase 1. Chromosomes line up at the equator Spindle fibers attach to each chromosome at the centromere, the center portion holding the sister chromatids together

D. Anaphase 1. Chromosomes separate and migrate to the opposite ends of the cell 1 copy of DNA to each end of the cell

E. Telophase 1. Reorganization spindle fibers disappear b) nuclear membrane forms 2. Chromosomes lengthen & disappear 3. Cytoplasm splits (cytokinesis) into two daughter cells Cell Plate forms for plant cells Chromosomes turn back into chromatin

F. Significance 1. TWO Daughter cells 2. Identical DNA to parent cell 3. Healing Growth Mitosis Animation Mitosis Animation has music but no narration, lasts about 1 minute

G. Cell Cycle From Individual Daughter cell  complete cell division Two Parts: a. Interphase: G1, S, G2 b. Mitosis/Cytokinesis Reminder: Cell Cycle is Interphase + Mitosis. Mitosis does not include interphase, it is just the process of cell division