Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
CELL GROWTH AND DIVISION Divide and Conquer WHY AREN’T CELLS HUMONGOUS? Exchanging Materials The larger the cell the larger the production of waste and need for food. Limited DNA More isn’t created when cell grows Not enough “information” to go around SURFACE AREA TO VOLUME Volume of a cube – L x W x H (X3) Surface area of a cube – H x W x Sides = (6) X2 X3 increases faster then X2 (V increases faster than SA) Cells need large surface area and low volume Helps diffusion of food and waste in and out CELL CYCLE Cells divide to solve problem of becoming too big Two Parts 1. Interphase 2. Mitosis INTERPHASE Interphase – period of cell growth and DNA replication 3 stages 1. Gap “G” 1 – Period of cell growth, new organelles and proteins created 2. S – Chromosomes replicate 3. Gap “G” 2 – More organelles and molecules are created CHROMOSOMES Made of DNA Carries genetic information Every species has a specific amount of chromosomes Humans have 46 chromosomes in each cell MORE ABOUT CHROMOSOMES Most of the time – Chromosomes can’t be seen – called Chromatin When cell is ready to divide – they duplicate and condense https://www.youtube.com/watch?v=N5zFOScowqo MITOSIS (REMEMBER PMAT) 4 phases 1. Prophase 2. Metaphase 3. Anaphase 4. Telophase PROPHASE Nucleus disappears Spindle fibers form (made of microtubles) Chromosomes are already condensed and duplicated but still joined at centromere Each side are sister chromatid METAPHASE Chromosomes line up in the middle Spindle fibers attach to centromere ANAPHASE Sister chromatids separate Pulled apart by spindle fibers TELOPHASE AND CYTOKINESIS Nuclear envelope forms around chromosomes Chromosomes uncondense Cell membrane pinches in the middle until two cells form FINAL RESULTS 2 identical daughter cells are created Same amount of DNA as original Return to Interphase G1 Stage Cells that are done growing (nerve, heart, etc) enter stage called G0 – no new divisions MITOSIS VIDEO http://youtube.com/watch?v=VlN7K1-9QB0