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Cell Theory

Cell Theory. Chapter 3 Biology Mr. Gilbertson. Hooke’s microscope. THE CELL. SMALLEST UNIT THAT CAN CARRY ON ALL PROCESSES OF LIFE UNICELLULAR - ONE CELL MULTICELLULAR - MANY CELLS. THE CELL THEORY. ALL LIVING THINGS ARE COMPOSED OF ONE OR MORE CELLS

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Cell Theory

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  1. Cell Theory Chapter 3 Biology Mr. Gilbertson Hooke’s microscope

  2. THE CELL • SMALLEST UNIT THAT CAN CARRY ON ALL PROCESSES OF LIFE • UNICELLULAR - ONE CELL • MULTICELLULAR - MANY CELLS

  3. THE CELL THEORY • ALL LIVING THINGS ARE COMPOSED OF ONE OR MORE CELLS • CELLS ARE ORGANISMS’ BASIC UNITS OF STRUCTURE AND FUNCTION • CELLS COME ONLY FROM OTHER CELLS BY REPRODUCTION

  4. People Who Contributed to the Cell Theory • Robert Hooke – credited with the discovery and naming of cells • Felix Dujardin – discovered the living fluid in a cell called “protoplasm” • Matthais Schleiden – German botanist who first proposed all plants and all plant parts are made of cells. Co-founder of cell theory • Theodor Schwann – German zoologist who proposed that all animals and all animal parts are made of cells. Co-founder of the cell theory. • Rudolf Virchow - published an influential theory that cells arose from each other in a continuous series of generations.

  5. The modern tenets of the Cell Theory include:  • All known living things are made up of cells. • The cell is structural & functional unit of all living things. • All cells come from pre-existing cells by division. (Spontaneous Generation does not occur). • Cells contains hereditary information which is passed from cell to cell during cell division. • All cells are basically the same in chemical composition. • All energy flow (metabolism & biochemistry) of life occurs within cells.    

  6. CELL DIVERSITY • SIZE • RANGE FROM 2M LONG TO .2 MICROMETERS IN DIAMETER • MOST ARE BETWEEN 20 TO 50 MICROMETERS IN DIAMETER • SIZE IS LIMITED BY THE SURFACE AREA TO VOLUME RATIO (AS SIZE INCREASES THE VOLUME INCREASES FASTER THAN THE SURFACE AREA) see page 55 • SHAPE • MOST ARE ROUGHLY CUBOIDAL OR SPHERICAL • TRISKADECKAHEDRON (13 FLAT SIDES) VERY COMMON • DIVERSITY OF SHAPE IS RELATED TO CELL FUNCTION • INTERNAL ORGANIZATION • PROKARYOTES - SIMPLE CELLS WITH NO NUCLEUS OR MEMBRANE BOUND ORGANELLES • EUKARYOTES - COMPLEX CELLS WHICH HAVE MANY MEMBRANE BOUND ORGANELLES

  7. LYMPHOCYTES

  8. ERYTHROCYTES

  9. CARDIAC MUSCLE

  10. NERVE CELLS

  11. ELODEA

  12. Common Features of Cells • Cell membrane – surrounds and encloses cell separates interior of the cell from the environment. • Cytoplasm – cell sap (fluid in which organelles are found. • Cytoskeleton – microscopic fibers which hold organelles in place and allow movement. • Ribosomes – protein factories • DNA – hereditary material.

  13. PROKARYOTE CELL

  14. Prokaryote • Bacteria are the best known and most studied form of prokaryotic organisms, • Discovery of a second group of prokaryotes, called archaea, has provided evidence of a third cellular domainof life and new insights into the origin of life itself. • Are unicellular organisms • Each cell in the colony is identical and capable of independent existence. • Are capable of inhabiting almost every place on the Earth, from the deep ocean, to the edges of hot springs, to just about every surface of our bodies.

  15. Prokaryotes Characteristics: • No nuclear membrane (genetic material dispersed throughout cytoplasm) • No membrane-bound organelles • Simple internal structure • Most primitive type of cell (appeared about four billion years ago

  16. EUKARYOTE ANIMAL CELL

  17. Evolution of Eukaryotes • Eukaryotes are generally more advanced than prokaryotes. There are many unicellular organisms which are eukaryotic, but all cells in multicellular organisms are eukaryotic. • It is hypothesized that a primitive bacterium once surrounded its food after releasing its digestive enzymes. The membrane folded inward and pinched off, creating the first digestive membrane-bound organelle. • This bacterium was engulfed by another and they developed a symbiotic relationship (endosymbiosis) • The engulfed bacterium evolved and became the mitochondria in present-day cells.

  18. Eukaryote Cells Characteristics: • Nuclear membrane surrounding genetic material • Numerous membrane-bound organelles • Complex internal structure • Appeared approximately one billion years ago Examples: • Paramecium • Dinoflagellates • Homo sapiens • All multicellular organisms

  19. EUKARYOTIC PLANT CELL

  20. PARTS OF A CELL • THREE MAIN COMPONENTS • CELL MEMBRANE -WHICH SURROUNDS AND SEPARATES THE CELL FROM ITS ENVIRONMENT • CYTOPLASM - LIES WITHIN THE MEMBRANE AND CONTAINS WATER, SALTS, AND SURROUNDS ORGANELLES • NUCLEUS - CONTAINS DNA AND DIRECTS CELL ACTIVITIES

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