Question

 

Compare and contrast these aspects below of electron microscopy with standard light imaging. (diffs/similarities)

a. Lens system (purpose and mechanism)
b. Information that can be concluded from acquired images apart from structure
c. Sample preparation (fixed, mounting for imaging)

Answer 1

light microscopy vs electron microscope

Lens: Both of the lenses are used to magnify the image of a specimen. In light microscopy the lens is glass made. visible light is used in the light microscope which can easily pass through the glass. A series of glass lenses help in focusing the object and magnify them. weather in electron microscopy the lens is not glass made but the it is elsctro magnetic lens. Since instead of light, electron beam is used in the elcotron microsope to develop the magnify image so glass made lens is not functional here. electrons are charged particles so electromagnetic field used in this lens stabilize the particles to generate the iimage. except this part, both of the lenses function in a similar way

light of electron source first falls on the object/specimen--------pass through the condenser it come to the objective lens-----then after passing through the projector lens the magnified image is generated to the eye (in light microscopy) or in the fluroscent screen (electron microscope).

b. Information of the acquired Image:

Similarities- In both cases the acquired image is magnified and so the details of the specimen could be studied..

Dissimilarities: The magnification of the electron microscope is much more than the lighit microscope so much more details of the specimen could be studied with electron microscope. In light microscope colour of the specimen is seen but in electron microscope black and white image is genetrated. In light microscope study of living organism is possible whereas its not possible in electron microscope. As the magnifiction is 10,00,000 x in electron microscope and 1000x in light microscope so ulltrastructure image could be obtain with a greater resolving power by electron microscope.

Sample prepartion:

There is a big difference in the sample preparation. In light microscope only mounting is enough to study a specimen (fixation process is need only if nessary). After mounting the specimen (mounting agent vary along with the specimen) on a glass slide its simply can be placed into the microscope.

sample preparation in electron microscope is a complex process. first sample is fixed with fixative (such as formaldehyde). The fixation process stebilize the structure which is necessary for image development. After ther dehydration of the sample is required in the alcohol series. The dried sample then needs to be mount on the metal stab using with a doubble sider of carbon tape for better conductivity. It also coated with the glod particles to stop the charge formation in the specimen.

Magnified image can been seen by naked eyes in the light microscope or phototograph can be taken with camera. But in electron microscope image is always is always generated in the fluroscent screen (electron cant be seen on naked eyes).