1. Interactive notes: pgs 95-100
The Cell Life Cycle
Interactive notes: pgs

2. Cell Reproduction Cell aptosis due to damage & suicide genes
Cell death
Cell populations maintained by cell division
Cell Division
2 daughter cells
Half the size of the original
DNA replication
DNA is duplicated
Nucleus divides during mitosis

3. Interphase Most of a somatic cells life cycle
G1: Cell growth & duplication of organelles
S: DNA replication & histone synthesis
DNA replication: strands unwind, DNA polymerase binds to exposed bases, new pairs are added to each strand
G2: Protein Synthesis
G0: not preparing for division (skeletal muscle and mature neurons never divide; stem cells never enter G0 as they divide constantly)

5. The M phase: Mitosis Prophase:
centrioles move to opposite ends of cell
spindle fibers connect to the centromere
of the duplicate chromatids
Metaphase: chromosomes align along the middle of the cell
Anaphase: centromere splits and chromatids separate
Telophase: Nuclear membrane reforms, nuclei enlarge, chromosomes visible again
Cytokinesis: Separation of Daughter cells

7. Mitotic Rate & Energy Use
The rate at which cells divide
Requires ATP
Malnourishment will result in stunted growth
Long live cells have a slower rate of mitosis
Stem cells: maintain the population of rapidly lost cells (digestive tract, skin, etc) by dividing repeatedly
Each time it divides: one cell specializes (skin cell, digestive cell) and the other continues to divide

8. Regulation of Cell Life Cycle
M-phase promoting factor (MPF)
trigger for cell division
Within the cell
Growth factors
Extracellular
Stimulate the division of certain types of cells
Repressor Genes inhibit cell division
Telomeres on DNA get shorter each time a cell divides: when it is too short repressor genes active

9. Cell Division & Cancer
When cell division exceeds cell death a tissue grows
Tumor: mass caused by uncontrolled division of cells
Benign: stays within originated epithelial or connective tissue
Malignant: uncontrolled growth to other tissues

11. Cancer
Illness characterized by mutations that do not control cell division
Mutations are called oncogenes
Tumor of origin is the primary tumor
Spreading called invasion
When malignant cells form a secondary tumor this is called metastasis