History of Cell Biology

Chapter 4, Section 1Video: Brief History of Cells

Robert Hooke English scientist (1635)Used a light microscope

to study natureLooked at a thin slice of

cork from the bark of a cork oak tree“great many little boxes”Reminded him of cubicles

or “cells” where monks lived QuickTime™ and a

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Anton van Leeuwenhoek

Dutch trader (1632)1st to observe living

cellsAlgae: SpirogyraProtists: Vorticella

Animalcules (protists)Made microscope 10x

that which Hooke usedKnown to have made over

500 different microscopes

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Matthias Schleiden

German Botanist (1804)

Concluded that all plants were composed of cells

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Theodor Schwann

German zoologist (1812)

Friend of Schleiden

Concluded that all animals are composed of cells

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Rudolf Virchow1821 German

PhysicianConcluded that all

cells come from other cells

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Cell Theory1. All living organisms are

composed of one or more cells.2. Cells are the basic units of

structure and function in an organism.

3. Cells come from the reproduction of existing cells.

Compound Light Microscope

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Two lenses to magnify an image

Eyepiece (ocular lens): magnifies usually 10x

Objective lens: enlarges the image 4x, 10x, 40x

Stage: platform that supports the slide

Light Source: light bulb Either light reflected with a

mirror or an incandescent small lamp

http://science.exeter.edu/jekstrom/JPEG/ELODEA~1.JPE

Elodea - green algae

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Paramecium

• Specimen has to be thin enoughfor light to pass through• Can see living organisms.

Transmission Electron Microscope (TEM)

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Transmits a beam of e- through thinly sliced specimen

Magnetic lenses enlarge the image

Can magnify up to 200,000x

Black and whiteCan not view living

specimens

http://www.pbrc.hawaii.edu/bemf/taura4_med.jpg

Virus in a fish gill cell

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VENTRICULAR MUSCLE CELLS

Scanning Electron Microscope (SEM)

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Sprayed with a fine metal coating

Beam of e- over the specimen’s surface

Causes metal coating to emit a shower of e- Project onto a

fluorescent screen Three-dimensional Add color Magnify up to 100,000x

http://www.abc.net.au/science/slab/cells/img/cell.jpg

Pfiesteria-toxic dinoflagellates

http://www.physiol.usyd.edu.au/daved/teaching/images/rbc.jpg

Red Blood Cells

Scanning Tunneling Microscope

http://www.engr.unl.edu/erc/images/afm.jpg

Uses needle-like probe to measure differences in voltage caused by e-

Computer tracks the movement of the electrons

Gives 3D imageAdds color

http://www.chem.utoronto.ca/staff/DHIRANI/stm-np.jpg

Gold Nanoparticles