Question

To study the details of protein molecules on the surface of a cell, a biologist would likely use a
Answer







compound light microscope








dissecting microscope








scanning electron microscope








transmission electron microscope

Answer 1

Proteins are very small so to see them you would need a powerful microscope. Light microscopes - like the compound 'scope and the dissecting 'scope won't cut it. And as for the difference between transmission electron microscopes TEMs and scanning electron microscopes (SEMs), TEMs bounce a beam of electrons off a slice or cross section of a sample. SEMs bounce a beam of electrons off the surface of a sample and reconstruct the surface details, depending on how the electron beam refracts...

Answer 2

scanning electron microscope is to see surfaces and transmission electron microscope is to see atoms because electrons passes through the specimen.

Answer 3

I don't think you can use TEM to see atoms, lol. That would be scanning tunneling microscope.

Answer 4

Plainly, Sam. But of the options given it was the most reasonable.

In all fairness, I have seen reasonable low resolution pictures of some of the larger macromolecular assemblies taken with TEMs and SEMs. Actin and myosin both stick out in my memory. Though some of the TEM techniques are getting close, cyroelectron microscopy in particular. Some groups have been able to resolve individual domains and secondary structural elements in certain proteins and suddenly having pictures to bear out or demolish the predicted structures all the molecular modellers have developed is causing some small angst in my field.

The point of the question was to distinguish between TEMs and SEMs. And the response was supposed to guide the person toward that distinction.