Transmission electron microscopy, Biology

Transmission electron microscopy:

Around 1931-32 two German scientists. Knoll and Ruska. Invented transmission electron microscopy, and built the first transmission electron microscope (TEM) in 1938 .Hillier 1940 built a high resolution TEM. A strong beam of electrons, issued from tungsten filaments, passed through vacuum  and focussed by electromagnets, producing a radiation wavelength   of about 0.0005nm is used to  illuminate objects in this electrons  strike against a fluorescent screen, or directly fall onto a photographic film, producing an electron micrograph. A practical resolution of about 5 a and magnification of one to several hundred thousand have been achieved by this  microscopy, combined with modern cytological techniques, this microscopy has enabled scientists to know of many  finer details of cell structure down to the macromolecular level. This knowledge of ultra structure or sub microscopic structure of the cell has resulted into the establishment of Molexular Biology.

Knoll (1935) demonstrated the feasibility of scanning electron microscopy achieving a resolution of about 30 a for three dimensional study of surface topography of objects in considerable details. Von Adrienne (1938) built first scanning electron microscope (SEM) .It is smaller and simpler than TEM. Electrons used SEM does not pass through the object, but are simply scattered from the surface of the object.              

Posted Date: 9/26/2012 7:10:05 AM | Location : United States







Related Discussions:- Transmission electron microscopy, Assignment Help, Ask Question on Transmission electron microscopy, Get Answer, Expert's Help, Transmission electron microscopy Discussions

Write discussion on Transmission electron microscopy
Your posts are moderated
Related Questions
Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

Chloroplasts is the disk-like organelles with the double membrane found in eukaryotic plant cells; contain thylakoids and are the site of the photosynthesis. ATP is produced durin

Enrichment of soil Indirect provision of minerals to grazing livestock includes mineral fertilization of  pasture and altering soil pH, however this may not be always feasible

Explain Gluten-free diet Gluten-free diet : It is a diet recommended for the patients with gluten enteropathy. Gluten is present in wheat, rye, barley and oats. Thus, foods co

What is plant coleoptile? Why does the removal of the coleoptile extremity disallow plant growth? Coleoptile is first (one or more) aerial structure of the sprouting plant that

CHF complicating IE is primarily the result of valve destruction or distortion or rupture of chordae tendinae. Intracardiac fistulas, myocarditis, or coronary artery embolization m

Explain about the term demand. Demand: Potential customers (consumers, buyers or households) of a good or a service into a market, which normally a demand curve is utiliz

Describe about The implant surgeon The implant surgeon should have basic knowledge of the macroscopic and microscopic anatomy of the jaw bones with their associated neurovascul

Degradation of Ecosystem Ancient man was simple-minded food gatherer and hunter. He looked upon nature with awe and respect and in fact he worshipped it. But from the time he

Use of micro-organisms to control insect pests, pathogens or weeds constitutes biological control, and the biological agents employed are called biocontrol agents. Micro-organis