The Cell Cycle, Mitosis, and Cancer Glencoe Biology Chapter

The Cell Cycle: The “lifetime” of a cell growth period= INTERPHASE G1, S, G2 G1, G2: cell Grows S: DNA Synthesis (duplicates) INTERPHASE S (DNA synthesis) G1 Mitosis G2 Cytokinesis MITOTIC (M) PHASE

The Cell Cycle NUCLEAR DIVISION = MITOSIS the cell’s nucleus and genetic material DIVIDE. Prophase, Metaphase, Anaphase, and Telophase (PMAT) INTERPHASE S (DNA synthesis) G1 Mitosis G2 Cytokinesis MITOTIC (M) PHASE

The Cell Cycle CYTOKINESIS: The cytoplasm divides, creating a new cell M-PHASE: MITOSIS + CYTOKINESIS INTERPHASE S (DNA synthesis) G1 Mitosis G2 Cytokinesis MITOTIC (M) PHASE

So what does this have to do with cancer? The cell cycle has 3 main checkpoints If a cell receives a go-ahead signal at the G1 checkpoint, it will continue dividing If the cell does not receive the go- ahead signal, it will exit the cycle and not divide Tumors form due to out of control cell division cancer cells video discovery of cell cycle video G1 checkpoint Control system S G1 M G2 M checkpoint G2 checkpoint

What causes cancer? Cancer is caused by mutations, which creates abnormal cell growth. A mutation is a change to an organism’s genetic material. In our case, DNA. CARCINOGENS: Agents that cause cancer. Radiation UV radiation X rays Chemicals Alcohol Tobacco Drugs Infectious agents Viruses like HPV What causes mutations?(changes our DNA?) Agents of Mutations = “MUTAGENS”:

Genetic Material names: Chromatin: Chromatin = DNA that is long and tangled Chromatin coils up (during M phase) to form chromosomes CHROMOSOME CHROMATID CENTROMERE duplicated, coiled DNA, = chromosome

VOCABULARY ! Human chromosome number: 46 in body cells (diploid OR 2N) 23 in sex cells (haploid OR N) A picture of species’ full set of chromosomes is a KARYOTYPE

Why do cells need to divide? unicellular organisms: Asexual REPRODUCTION (only needs one parent; no genetic variation; mitosis) Multicellular organisms depend on cell division for: Growth Repair 2 Types of cell division: MITOSIS: MAKES SOMATIC/BODY CELLS/unicellular organisms (creates GENETICALLY IDENTICAL cells) MEIOSIS: MAKES SEX CELLS (GENETICALLY DIFFERENT CELLS). Sexual organisms. Creates genetic variation

INTERPHASE – BEFORE MITOSIS

1st stage of Mitosis: Prophase Chromatin coils up into visible chromosomes nucleus disappears Centrioles begins to separate

2nd Stage of Mitosis: Metaphase Spindle fibers pull the chromosomes to the middle (equator/metaphase plate) of the cell

3rd stage of Mitosis: Anaphase During Anaphase… Chromosomes are pulled apart forming chromatids. chromatids move towards opposite sides of the cell.

4th stage of Mitosis: Telophase chromatids uncoil, becoming chromatin nuclear envelope reforms Mitosis is COMPLETE!!!

Cytokinesis: last stage in the cell cycle cytoplasm divides into 2 new cells ANIMAL CELLS: The cell membrane will move inward and pinch apart PLANT CELLS: A new cell wall forms between the two new cells (CELL PLATE)

SUMMARY - MITOSIS Number of ROUNDS of cell divisions: 1 Number of daughter cells : 2 Genetically identical? Yes Chromosome #: Same as parent Where: Somatic cells (non-sex cells) When: Throughout life Role: Growth and repair