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Cellular Reproduction
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How Do Cells Receive Nutrients? Cell Membrane –The membrane allows in: Food Water Oxygen
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The Cell Membrane Selectively permeable – allows only certain materials to pass through. Diffusion – the movement of molecules from areas of higher concentration to areas of lower concentration Osmosis – the movement of molecules from areas of higher to areas of lower concentration through the cell membrane.
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The Cell Membrane Three types of solution Hypotonic Note: = Water = Concentration
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The Cell Membrane Three types of solution Isotonic Note: = Water = Concentration
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The Cell Membrane Three types of solution Hypertonic Note: = Water = Concentration
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The Cell Membrane Three types of solutions Hypotonic Isotonic Hypertonic The concentration of water outside of the cell is: Higher SameLower
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The Cell Membrane Three types of solutions Hypotonic Isotonic Hypertonic The concentration of dissolved substance outside of the cell is: LowerSameHigher
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The Cell Membrane Three types of solutions Hypotonic Isotonic Hypertonic The cell contents will: SwellStay the sameShrink
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The Cell Membrane The concentration (amount) of dissolved substance affects the movement of water into and out of the cell.
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The Cell Membrane Homeostasis – the ability of an organism to maintain a constant internal balance even when the conditions around it change. Examples: 1.Turgor Pressure – the force of the cell contents pushing against the cell wall
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The Cell Membrane 2.Passive Transport – the movement of substances through the cell membrane without using energy. 3.Active transport – the movement of molecules from areas of lower to higher concentration with the use of energy.
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The Cell Membrane Protein Molecules Lipid Molecules
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Surface Area to Volume Ratio Cell Diameter increases 10 times Surface Area increases 100 times Volume increases 1000 times
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Surface Area to Volume Ratio Double the cell size (2 times) –8 times more nutrients required –8 times more waste to excrete –Surface area increase only 4 times Cell starve to death or be poisoned
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Why is it important to have many small cells rather than one Larger cell? Larger cell has: –Difficulty in receiving enough nutrients and oxygen –Difficulty in removing wastes –One copy of DNA
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Cell Division Cell divides into two daughter cells
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Mitosis Process by which the nucleus of the cell is divided into two nuclei, each with the same number and kinds of chromosomes as the parent cell.
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Interphase G1 phase –Cellular Growth –Development S phase –DNA Replication –Protein synthesis G2 phase –Synthesis of organelles –Materials for cell division
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Interphase
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Chromosomes Contain the genetic information (DNA) that is passed from one generation of cells to the next.Contain the genetic information (DNA) that is passed from one generation of cells to the next.
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DNA Proteins (histones) Chromosomes
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Chromosome Structure Sister Chromatid Centromere DNA
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Number of Chromosomes OrganismChromosome Number Amoeba50 Carrot18 Cat32 Chimpanzee48 Dog78 Earthworm36 Goldfish94 HUMAN46 Lettuce18
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Prophase Appearance of chromosomes Nucleolus disappears Nuclear membrane breaks down Centrioles separate and migrate to opposite poles of cell Spindle fibers from the centrioles attach to the centromeres Chromatin coils up (shortens) into chromosomes Longest (50 - 60%)
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Prophase
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Metaphase Chromosomes line up across center (equator) of cell Spindle fibers from centromere to centrioles Shortest
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Metaphase Chromosome Centriole Spindle Fiber
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Anaphase Sister Chromatids split at Centromere Individual Chromosomes move toward poles Chromatid pairs from each chromosome separate from each other Chromatids are pulled apart by the shortening of the microtubules in the spindle fibers
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Anaphase
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Telophase Spindle fibers breakdown Chromosomes uncoil into Chromatin Nuclear envelope (membrane) reforms Nucleolus becomes visible Chromosome reach the ends of the cell The centrioles double The cytoplasm is divided Final Phase
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Telophase
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Mitosis in Whitefish and Onion
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Cytokinesis The process by which the cytoplasm divides, forming two new cells.
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Cytokinesis Animals –Cell membrane –pinches inward Plants –Cell plate
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Result of Mitosis Two cells that are identical to each other.
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Cell Theory Developed by Robert Hooke Came up with the name cells Encouraged other scientists to look for cells in their research Cell theory is made up of three main ideas:
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Cell Theory 1.All organisms are composed of one or more cells. –Most organisms are multicellular 2.Cells are the basic units of structure and function in organisms 3.All cell arise from existing cells –Cell theory states that a cell divides to form two identical cells
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Cancer
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“When Cell Division Goes Bad”
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Cancer Uncontrolled cell growth creating a malignant tumor
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Tumor A growth from a single mutated cell that has repeatedly undergone cell division
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Malignant A tumor that invades surrounding tissue and spreads to other parts of the body
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Benign A tumor that does not invade surrounding tissues and does not spread
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Metastasize The spread of cancer from the place of origin throughout the body –The cancer migrates and invades tissues
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Causes of Cancer Heredity -- Breast Cancer, Retinoblastoma Changes in enzymes production Carcinogens -- environmental agent –Tobacco (smoke and smokeless), saccharin, pesticides, herbicides, asbestos, benzene, water polution Radiation -- UV light, X-rays, nuclear bombs Viruses -- papillomavirus
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Types of Cancer Breast Lung Prostate Colon/Rectum Bladder Lymphoma
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Types of Cancer Uterus Skin (melanoma) Oral Cancer Leukemia Pancreas Ovary Testicular
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Treatments for Cancer Surgery -- the actual removal of the tumor and other infected areas Chemotherapy -- the use of a drug to selectively kill off cancer cells Radiation -- mutating the dividing cells to stop them from dividing
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Prevention Low fat diet High fiber diet Vitamins and minerals Daily Exercise Not using tobacco
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