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Section 2: Discovering Cells

Section 2: Discovering Cells. I. First Sightings of Cells. Robert Hooke: English scientist and inventor 1663 observed a thin slice of cork Coined the term “cells”. Robert Hooke. 1665, he published Micrographia Described his microscope, “cells”, Astronomy, and Paleontology.

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Section 2: Discovering Cells

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  1. Section 2: Discovering Cells

  2. I. First Sightings of Cells • Robert Hooke: • English scientist and inventor • 1663 observed a thin slice of cork • Coined the term “cells”

  3. Robert Hooke • 1665, he published Micrographia • Described his microscope, “cells”, Astronomy, and Paleontology

  4. Robert Hooke’s Microscope

  5. Anton van Leewenhoek Diatoms Anabaena (Cyanobacteria) • Constructed simple microscopes • Observed pond water and called the organisms, “animalcules” • Animalcules mean little animals

  6. Matthias Schleiden 1838, he concluded that all plants are made of cells

  7. Theodor Schwann 1839, concluded that all animals are made of cells

  8. Rudolf Virchow • 1855, proposed the idea that cells come from existing cells

  9. II. Cell Theory Spirogyra • Cell Theory combines the observations and statements of these scientists: • Matthias Schleiden • Theodor Schwann • Rudolf Virchow • Anton van Leewenhoek

  10. Cell Theory Cell Theory States: All living things are composed of cells. Cells are the basic unit of structure and function in living things. All cells are produced from other cells.

  11. III. Microscopes • Microscope: an instrument that makes small objects look larger • Microscope uses lenses to make objects look larger.

  12. Daily Question 2/19 • Name at least 3 parts of the cell. • Name at least one part of the cell theory. • Do not look it up or ask your neighbors.

  13. 1. Magnification • Magnification: bending of the light to make the objects look larger • Convex lens: center of the lens bulges outward

  14. Magnification Eye Piece Objective lens • Compound Microscopes • Have multiple lenses to greatly increase the magnification

  15. Magnification Total Magnification = (Eye Piece Magnification) x (Objective Lens Magnification) Example: Eye Piece = 10x Objective Lens = 40x Total Magnification = (10) x (40) Total Magnification = 400x

  16. 2. Resolution Low Resolution High Resolution Resolution: the sharpness of the image

  17. Electron Microscopes • Developed in the 1930s, it produces higher resolution than light microscopes • Uses a beam of electrons instead of visible light

  18. Scanning Electron Microscope 3-D Image of a dust mite 120 nanometers long! Scanning Electron Microscope

  19. Words Bank for Microscope Stage Revolving Nosepiece Base Stage Clips Arm Illuminator Eyepiece Coarse Adjustment Knob Objective Lenses Diaphragm Fine Adjustment Knob Inclined Head

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