Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
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.
OBJECTION OF CELL THEORY (REASONS OF DISCARTION) (i) Living organism are composed of various types of cells and their product but members of monera & protista don't have
How are the male gametophytes and the male gametes formed in angiosperms? In the anthers of every stamen there are pollen sacs. Within the pollen sacs there are microspore moth
Explain about the Lignans? Lignans are diphenolic compounds formed by dilnerization of 2 cinnamic acid residues. Most lignans apparently pass through the GIT as fibre. Some lig
what is almentary canal
Coevolutionary relationships between parasites and their hosts can be more complicated than between predators and their prey. As in the case of prey-predator relationship, one can
Drawbacks of Lamellar model This model does not explain the elasticity of PM. Although this model says that PM is elastic but it also states that head of lipid molecules is
Periodicity (Phenology, Aspection) It refers to the study of seasonal changes in the community, that is, the periodic phenomena of organisms in relation to their climate. Peri
Normal 0 false false false EN-IN X-NONE X-NONE
What is normal bone physiology An insight into the normal bone physiology and its adaptation by modeling and remodelling process to functional stresses is also of importance. I
project
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd