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.
Q. Properties of foods? various properties of foods, under which the quality attributes of foods were introduced to you in terms of food quality and its categories as appearanc
A red blood cell has an internal salt concentration of 150mM. The cell is placed in a beaker of 500mM salt. (a) Assuming that the cell membrane is permeable to water but not to
Some animals, such as cows, normally make only one offspring from each mating. If a cow showed a dominant phenotype, why would a typical testcross be a complex way to verify the ge
Explain the Prevalence of Iodine Deficiency Disorders? We can determine the prevalence of IDD by conducting population surveys. Most of the population surveys are based on clin
Q. How does the CD4 counting act to monitor the HIV infection? What is another laboratory method to follow up the disease? The CD4 counting test is complete from a blood sample
FUNCTION S - (a) It is antagonistic to glucagon. Insulin decreases the level of glucose in the blood. It acts by increasing the rate at which glucose is transported out of the
What is osteoblast The osteoblast is the key for the development of new bone. It is essential that a large number of osteoblasts accumulate on the implant surface(contact osteo
Q. What are the major structures of the human eye? The major structures of the human eye are the iris, the cornea, the pupil, the ciliary muscles, the crystalline lens and the
Food Which can be Taken in Plenty and Food to be Avoided Lastly, in the context of changing the diet, we should know the foods to be avoided and the food to be taken in plenty
Q. How to investigate aortic stenosis by Exercise Testing? Exercise testing is relatively contraindicated in patients with aortic stenosis. Its diagnostic accuracy to pick up a
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