CONTRIBUTIONS TO THE CELL THEORY

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CONTRIBUTIONS TO THE CELL THEORY

• Timeline of scientists and their discoveries

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1) Anton von Leeuwenhoek

• 1600s
• Dutch businessman
• Invented 1st simple light microscope

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Anton von Leeuwenhoek (cont)

• Observed tiny organisms in pond water
• Organisms were nicknamed wee beasties

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2) ROBERT HOOKE

• 1665
• English physicist
• Observed flowers, insects, and plant tissue

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ROBERT HOOKE (cont)

• Observed thin slices of cork (oak tree)
• Coined the term cell based on the rooms in a
  monastary

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3) ROBERT BROWN

• 1833
• Observed plant cells under the microscope

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ROBERT BROWN (cont)

• Observed a dark structure inside each cell and
  coined the term nucleus

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4) MATTHIAS SCHLEIDEN

• 1838
• German botanist scientist who studies plants
• Concluded all plants are made up of cells

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5) THEODORE SCHWANN

• 1839
• German biologist
• Concluded all animals are made of cells

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6) RUDOLF VIRCHOW

• 1855
• German Physician
• Studied cell reproduction
• Concluded all cells arise from preexisting cells

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The cell theory

• 1. All living things are composed of cells
• 2. Cells are the basic unit of structure and
  function in living things.
• 3. All cells arise from preexisting cells.

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Introduction to Cells

• Chapter 6

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Levels of Organization

• All living organisms can be studied on many
  levels
• From smallest to largest they are
• Chemical (atoms molecules)
• Cells
• Tissues
• Organs
• Organ Systems
• Whole Organism

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Basic Structure of Cells

• All cells have a cell membrane and cytoplasm
• Cell Membrane thin, flexible barrier around cell
• Composed of lipids and proteins
• Cytoplasm jelly-like material inside the cell
• All cells contain organelles
• Organelles small structures that perform
  different functions within a cell

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Prokaryotic Cells

• Do NOT have a nucleus
• Instead a small ring of DNA is free-floating in
  center of cell
• Organelles do NOT have a membrane
• i.e. bacteria (very simple organisms)

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Eukaryotic Cells

• Contain a nucleus
• Organelles are membrane-bound
• Much more complex
• i.e. plants, animals, fungi

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