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. - PowerPoint PPT Presentation
Section 2: Discovering Cells
Section 2: Discovering CellsI. First Sightings of CellsRobert
Hooke:English scientist and inventor1663 observed a thin slice of
cork
Coined the term cells
Robert Hooke1665, he published Micrographia
Described his microscope, cells, Astronomy, and Paleontology
Robert Hookes Microscope
Anton van LeewenhoekConstructed simple microscopesObserved pond
water and called the organisms, animalculesAnimalcules mean little
animals
Anabaena (Cyanobacteria)DiatomsMatthias Schleiden1838, he
concluded that all plants are made of cells
Theodor Schwann1839, concluded that all animals are made of
cells
Rudolf Virchow1855, proposed the idea that cells come from
existing cells
II. Cell TheoryCell Theory combines the observations and
statements of these scientists:Matthias SchleidenTheodor
SchwannRudolf VirchowAnton van Leewenhoek
SpirogyraCell TheoryCell 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.
III. MicroscopesMicroscope: an instrument that makes small
objects look larger
Microscope uses lenses to make objects look larger.
Daily Question 2/19Name 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.1. MagnificationMagnification: bending of the light to
make the objects look largerConvex lens: center of the lens bulges
outward
MagnificationCompound MicroscopesHave multiple lenses to greatly
increase the magnification
Eye PieceObjective lensMagnificationTotal Magnification = (Eye
Piece Magnification) x (Objective Lens Magnification)
Example:Eye Piece = 10xObjective Lens = 40x
Total Magnification = (10) x (40)
Total Magnification = 400x2. ResolutionResolution: the sharpness
of the image
Low ResolutionHigh ResolutionElectron MicroscopesDeveloped in
the 1930s, it produces higher resolution than light microscopesUses
a beam of electrons instead of visible light
Scanning Electron Microscope
3-D Image of a dust mite 120 nanometers long!Scanning Electron
MicroscopeWords Bank for MicroscopeStageRevolving
NosepieceBaseStage ClipsArmIlluminatorEyepieceCoarse Adjustment
KnobObjective LensesDiaphragm
Fine Adjustment KnobInclined Head
