Cell Cycle Mitosis Regulation Internal and external factors

Cell Cycle Mitosis

• Regulation • Internal and external factors regulate cell division. • Cancer is the uncontrolled growth and division of cells. • Cancer cells can kill an organism by crowding out normal cells, resulting in the loss of tissue function.

Cancer cell normal cell bloodstream metastasize Benign Malignant

• Causes of Cancer • Internal Factors – Inheritance – Mutations Skin Cancer • External Factors » Carcinogens are substances that are known to produce and promote the development of cancer. – Radiation – Chemical – Viruses

Why do cells divide? ? SA to volume ratio. . . 3 2 1 SA= 6 SA= 24 SA= 54 VOL= 1 VOL= 8 VOL= 27 Ratio= 6: 1 Ratio= 24: 8 or 3: 1 Ratio: 54: 27 or 2: 1 Less SA: VOL Therefore … can’t get too big … MUST DIVIDE Mitosis Lessss SA: VOL

Chromosomes vs. DNA

Chromatin All the DNA/proteins in nucleus … condenses to form chromosomes during Mitosis Chromatid Sister chromatid Chromosomes Condensed chromatin. . Either 2 sister chromatids or 1 chromatid Nucleus Sister chromatid

Cell Cycle Mitosis se (cell grows) Cell Div. e has p a t me p inesis pha Cytok se a ph lo te ana phase e as h rp te In ha p ro se phase (getting’ ready) phase (DNA replicates)

Interphase DNA replicates Metaphase • Centrioles opp. sides • chromos. line up at middle Mitosis Prophase • Chromosomes condense … attached at centromere • Spindle apparatus begins to form Anaphase Telophase Cytokinesis Cell Division Interphase Cytokinesis New nuclear membranes form 2 daughter cells. . Identical to each other and parent cell

v e R w ie Mitosis