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Microscopes & Cell theory. Microscope development:. Hans and Zacharis Janssen: 1590 –simple microscope; 2 lens in a tube Anton van Leeuwenhoek : early 1660’s- used microscope to observe nature & recorded it. Describe the properties of microscopes. Microscope: magnifies images

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Microscope development
Microscope development:

  • Hans and Zacharis Janssen: 1590 –simple microscope; 2 lens in a tube

  • Anton van Leeuwenhoek: early 1660’s- used microscope to observe nature & recorded it.


Describe the properties of microscopes
Describe the properties of microscopes.

  • Microscope: magnifies images

  • Magnification: increase in size

  • Resolution: increase in detail

  • Two types:

  • Light microscopes

  • Electron microscopes


Light microscopes
Light Microscopes

  • Magnifies objects using light

  • Simple microscopes: have only one lens (magnifying glass)

  • Compound light microscope: has two lenses


Using the microscope
Using the microscope:

  • Find total magnification: multiply power of eyepiece (usually 10X) x power of objective lens

  • When focusing: always start with LOW POWER objective

  • Move nosepiece all the way down and focus slowly UPWARD using the coarse adjustment


Electron microscopes
Electron Microscopes

  • 1940’s, uses electron beams instead of light

  • Allows more detail, but specimens are usually killed in the staining process

  • Two types:

  • TEM: beam goes through specimen

  • SEM: scans surface only


Parts of a microscope
Parts of a microscope

  • Ocular lens: lens near eye

  • Eyepiece: holds ocular lens

  • Objective lens: lens near specimen

  • a. high power lens: longer, usually 40 X

  • b. low power lens: shorter, usually 10 X

  • Nosepiece: holds objective lenses

  • Stage: platform supporting specimen

  • Diaphragm: regulates amount of light

  • Fine adjustment/coarse adjustment: used to focus on object

  • Arm: supports microscope

  • Illuminator: light source


How did the Cell Theory come about?

  • Robert Hooke discovered cells in 1665

  • Examined a wine cork(tree)

  • looked like his monastery cell so he named them “cells”


Schwann

Schleiden



The cell theory
The Cell Theory cells

  • All organisms are made up of cells

  • Cell is the basic unit of organization

  • Cells come from pre-existing cells


Stem cell research
Stem Cell Research cells

Website-stem cell animation

http://www.sumanasinc.com/webcontent/anisamples/stemcells.html


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