Explain why electron microscopes cannot be used to view the scructure of living cells?

Question

Explain why electron microsopes cannot be used to view the structure of living cells

Answer 1

Just to clarify some wrong things being said:

Transmission electron microscopes require a vacuum to function, as far as I know. This is typically detrimental to cells, but some bacteria have survived in vacuums. However, TEM requires some staining that's pretty toxic, and coupled with the fact that you're beaming 20+ kilovolt electron beam through the sample means that the cells won't live through the procedure.

TEM is transmission, that means you're not looking at scattered electrons, you're looking at what passes through the sample, which is why thick things are dark and thin things are light. TEM can be performed on whole cells or thin sections prepared with a microtome.

scanning electron microscopy is normally performed in a vacuum, but some recent advances have resulted in ambiant pressure/moisture sample holders. we looked into using it to look at the polysaccharide capsule of C. perfringens, but opted against it as it's prohibitively expensive.

Samples used in SEMs are usually coated with a thin layer of gold (sometimes I've seen platinum in protocols). However, contrary to popular belief this isn't done to make things more reflective of the electron beam.

For starters, in an SEM (or it's better cousin, field-emission SEM), the electron beam is considerably less energetic, we ran ours at 1 kEV. This means the electrons are much less likely to penetrate your sample. Second, the electrons accumulate in the sample and need to be discharged, or grounded. If you don't coat your sample, they don't efficiently discharge and you get "charging", which among other things makes your picture look like crap. The glold particles provide a path for grounding of the built up electrons.

SEMs can be used on intact bacterial cells, or intact whatever cells, or all sorts of inorganic samples. I can assure you that when people look at the surface characteristics of some sort of carbon polymer, it's NOT sputter coated to make it reflective :P

Anyhow, the vacuum and electron beam and being coated with a thin layer of gold in an partial vaccuum w/ argon displacing the atmospheric gasses will again conspire to kill your samples.

edit: atomic force microscopy can view living cells.

Answer 2

An electron microscope works by measuring the electrons bouncing off minuscule gold particules used to stain a cell. Much like an X-ray only works by measuring the rays bouncing off bones.

So you have to stain the cell with gold which effectively kills the cell but allows you to have very precise imaging.

Answer 3

With the scanning electron microscope the specimins must be very thin and are usually coated with a thin film of gold. Live specimens are to large and move around. The electron scans the surface of the specimen. The beam excites the electrons the samples surface. and you get a great view

Answer 4

the answer pretty much lies in your question itself.
only dead cells and the structures can be viewed as it applies the use of electrons in vaccum .. moreover to prepare a cell for viewing in an electron microscope the cell will be heat fixed and has to be processed to determine the minute details in it... so obviously the cell will be a dead one...

Answer 5

Because electron microscopes mostly see's non complex non organic matter are cell are to large and complex to be viewed on a electron microscope for example you can't tell whats in a house by just looking outside of it or even what its made out of you would tare the house and its contants apart peace by peace.

Answer 6

False because because the specimen would need to be in a vacuum. True 50X10=500 True because you can't look through a lens using a SEM. It's bouncing electrons off a specimen. I'm saying true.

Answer 7

The necessary vacuum tends to kill anything you put in the chamber. Also, the electron beam itself doesn't do them any good.

Answer 8

this is because the object under observation in this requires to be placed in vaccum, and hardly any living cell can sustain life in such condition.

Answer 9

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Science Nerds!!!!!