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The electron microscope and biological advancement.

Extracts from this document...

Introduction

Toby Nicholson

The electron microscope and biological advancement

What is an electron microscope?

        An electron microscope does a similar job to an ordinary optical microscope that many people will have used before - it makes objects appear bigger. This is called magnification and lets one see details of very small objects, such as cell structures, which cannot be seen with the naked eye. In a normal optical microscope this is achieved by using higher-power lens that magnify the image more times.

However, there comes a point at which magnification of an optical microscope does not show more detail. This is to do with the physical nature of light. Light is made up of particles (called photons) that travel in a wave. We can only see that two objects are separate if light can pass between them. Light can pass between the letters on this page so you can see them. When objects are very close together light cannot pass through them and they appear as one object.

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Middle

The surface features of an object or "how it looks", its texture. There is a direct relation between these features and materials properties (hardness, reflectivity...etc.)

  • Morphology

The shape and size of the particles making up the object. This relates between their structures and materials properties (ductility, strength, reactivity...etc.) image02.png

  • Composition

The elements and compounds that the object is composed of and the relative amounts of them; direct relationship between composition and materials properties (melting point, reactivity, hardness...etc.)

  • Crystallographic Information

How the atoms are arranged in the object. We can deduce from this a relation between these arrangements and materials properties (conductivity, electrical properties, strength...etc.)

(www.unl.edu/CMRAcfem/em.htm, 13/10/02, University of Nebraska Lincoln)

        It is clear to seen the advantage of the electron microscope with the comparison of these two slidesimage03.pngimage04.png

What have electron microscopes done for biology?

Although the electron microscope has advanced many different areas of science, the particular area biology that has been most helped has been the understanding of cell ultra structure or microbiology.

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Conclusion

Conclusion

        In conclusion the electron microscope is a huge leap forward is microscopy as it has a mush larger resolving power, this has aided microbiologists greatly allowing them to see cell ultra structure as well as viruses and even analyse DNA. The principal part of what is known about cell ultra structure is thanks to the electron microscope. It allows for an understanding of all things small from insects, to bacteria, to DNA. I has also helped supported the theory of evolution and contributed to forensic science.

Bibliography

        Indge,B etal

        2000

        A New Introduction To Biology

        Hodder & Stoughton

        ISBN 0 304 78167X

        Iowa State University

mse.iastate.edu/microscopy/insects.html, 13/10/02

        University of Nebraska Lincoln

www.unl.edu/CMRAcfem/em.htm, 13/10/02

Roberts, B etal

1993

Biology Principles and Processes

Thomas Nelson and Sons Ltd

ISBN 0-17-448176-4

Encyclopedia Britannica CD-ROM Deluxe Edition

1994-2001

 New York State Police Forensic Department

www.troopers.state.ny.us/ForSc/ModFor/E-Micro.html, 14/10/02

...read more.

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