The Cell Cycle http://www.nclark.net/MitosisRap.mp3

Cell Division: Key Terms Somatic cells (body cells) Gametes (reproductive cells): sperm and egg cells Genome: cell’s genetic information Chromosomes: DNA molecules Diploid (2n): 2 sets of chromosomes Haploid (1n): 1 set of chromosomes Chromatin: DNA-protein complex Chromatids: replicated strands of a chromosome Centromere: narrowing “waist” of sister chromatids

General info. ~ 10 trillion cells in body all from one cell by mitosis. Erythrocytes (RBC) made one million per second Cell division (mitosis) Single celled = more individuals Multi-celled = growth, differentiation and repair. 2 basic function Duplicate the cell Ensure daughter cell has complete copy DNA The basic steps are Duplicate the DNA Divide the chromosomes into two complete sets Divide the cell into two daughter cells Same for Prokaryotes and Eukaryotes http://highered.mcgraw-hill.com/sites/0073031216/student_view0/exercise13/mitosis_movie.html http://www.nationalgeographic.com/adventure/video/index.html

The Cell Cycle http://www.sinauer.com/cooper/4e/animations1601.html Cell Life Cycle. Stages of Cell Growth Interphase (90% of cycle) G1 phase: primary growth phase. Cell does its 'job'. S phase: DNA replication G2 phase: Chromosome condensation, cell organelle replication Mitotic phase M phase: mitosis (nuclear division) C phase: cytokinesis (cytoplasmic division) daughter cells form http://www.sinauer.com/cooper/4e/animations1601.html http://highered.mcgraw-hill.com/sites/0072437316/student_view0/chapter11/animations.html#

Mitosis Prophase Prometaphase Metaphase Anaphase Telophase http://www.johnkyrk.com/mitosis.html http://www.sumanasinc.com/webcontent/animations/content/mitosis.html

Prophase Pairs of Chromosomes (sister chromatids) visible Nucleoli disappear Mitotic spindle forms Centrosomes (centrioles) move

Prometaphase Nuclear membrane fragments Spindle fibers interaction with chromosomes Kinetochore develops

Metaphase Chromatid pairs meet in the Middle of the cell Centrosomes at opposite poles Kinetochores of sister chromatids attached to microtubules (spindle)

Anaphase Sister chromatids come Apart Chromosomes move to opposite poles Each pole now has a complete set of chromosomes

Telophase Cytokinesis occurs forming Two new cells Daughter nuclei form Nuclear envelopes arise Chromatin becomes less coiled Two new nuclei complete mitosis http://www.loci.wisc.edu/outreach/bioclips/CDBio.html

Cytokinesis Cytoplasmic division Animals: cleavage furrow Plants: cell plate http://biology.nebrwesleyan.edu/benham/mitosis/

http://www.nobelprize.org/educational/medicine/2001/cellcycle.html Cell Cycle regulation Growth factors Cyclins control the cell cycle , causing movement from G1 to S or G2 to M Cdk (cyclin dependent kinase) work with cyclins MPF (Maturation Promoting Factor) includes CdK and cyclins p53 blocks cell cycle if DNA is damaged. Density-dependent inhibition crowded cells stop dividing Anchorage dependence to divide cells must be attached to a substrate or tissue matrix http://www.sinauer.com/cooper/4e/animations1604.html

Cancer http://www.hhmi.org/biointeractive/media/angiogenesis-lg.mov Uncontrolled, rapid cell division Cancer cells: ignore cell cycle regulation signals break away and settle in other parts of the body (metastasis) don’t maintain function consume lots of resources Mutagens that change genes cause cancer (Carcinogens) Oncogenes turn on cell division normally silent if moved they become active Cancer cells are believed to be immortal. Tumor: benign (harmless) or malignant (harmful) http://www.metacafe.com/watch/1872431/3d_medical_animation_what_is_cancer/ http://www.hhmi.org/biointeractive/media/angiogenesis-lg.mov

Differentiation http://www.pbs.org/wgbh/nova/sciencenow/3209/04.html Specialization and division of labor. Pre-differentiation are stem cells Totipotency: ability of a cell to divide and produce all the differentiated cells in an organism Each cell has all the instructions (DNA) to produce a whole human Nearby cells and/or the external environment triggers differentiation Ensures efficiency in multicellular organisms Groups of cells differentiate to form tissues and organs http://www.cnn.com/SPECIALS/2001/stemcell/