Transmission electron microscopy, Biology

Assignment Help:

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.              


Related Discussions:- Transmission electron microscopy

What is a homologue, Single chromosome of a pair is known as homologue.In H...

Single chromosome of a pair is known as homologue.In Homologous pair two identical chromosomes are there. Each one chromosome in a Homologous pair is known as Homologue.

Cell cycle, what is the process of cell cycle?

what is the process of cell cycle?

How would a glycosidic bond present, A glycosidic bond would be present in:...

A glycosidic bond would be present in: Select one: a. acetone. b. methyl-alpha-D-glucose. c. 2-deoxy-beta-D-ribose. d. glucose-6-phosphate. e. fructose-1, 6-bisphosp

Define clostridium perfringens-associated gastroenteritis, Q. Define Clostr...

Q. Define Clostridium perfringens-associated gastroenteritis? Clostridium perfringens-associated gastroenteritis is a food borne disease which is frequently reported and is

Preprocedure care, BRONCHOSCOPY: Bronchoscopy is the passage of lighte...

BRONCHOSCOPY: Bronchoscopy is the passage of lighted bronchoscope into the bronchial tree. Bronchoscopy may be performed with  rigid steel of flexible fiberoptic instruments.

Sausage classification - meat products, S a u s a g e classification ...

S a u s a g e classification Classification                                      Examples Cooked-smoked                               Frankfurters, Bologna, Mortadel

Transparency - aquatic habitats, Transparency - Aquatic Habitats Trans...

Transparency - Aquatic Habitats Transparency affects the extent of light penetration. It is indirectly related to turbidity. Suspended particulate matters such as clay, silt a

Saturated fatty acids required for dyslipidemia, Q. Saturated Fatty Acids r...

Q. Saturated Fatty Acids required for dyslipidemia? Saturated Fatty Acids (SFA): These are found mostly in animal fats as white marble-like solid at room temperature. Red meats

Phylum platyhelmenthiese, show heading wise characteristics of phylum platy...

show heading wise characteristics of phylum platyhelmenthiese

Receptors - ear, EA R It is phono receptor as respond to sound...

EA R It is phono receptor as respond to sound waves. It is teloreceptor as receive stimuli from far distance. It is stato-acousting organ as concerned with b

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

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!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd