Microscopes

Milan is a scientist studying the geometry of different types of viruses. She uses a particular type of microscope to generate the three-dimensional image of the surface shape of adenoviruses shown below. The image is magnified 125,000x.   

What type of microscope must have Milan used to generate this image of adenoviruses?

• Compound light microscope

• Simple (single-lens) light microscope

• Scanning electron microscope (SEM)

• Transmission electron microscope (TEM)

Light microscopes are widely useful tools for viewing cells and tissues.  However, light microscopes are limited by the wave-like nature of light; as the magnification increases, the image is less clear. Most light microscopes only magnify an image up to 1000x, or possibly up to 2000x, larger.

If a student needed to view a cell structure at much higher magnification (such as 100,000x magnified), how would the student be able to generate a clear image?

• They should use a brighter light source to illuminate the side. 

• They should use an electron microscope such as an SEM or TEM.

• They should use a lower-power objective lens in the microscope.

• They should stack the eyepiece lenses from multiple light microscopes.

Which microscope(s) would he use to complete the examination? Nicholas went to the community pond and collected samples. He wants to examine the internal structures of the organisms found in his sample. 

Use the table to help you determine your answer.

Which microscope(s) would he use to complete the examination?

• Scanning Electron

• Compound Light

• Transmission Electron

• Scanning Electron or Transmission Electron

Which of the following microscopes would be BEST to observe a living organism in pond water?

• Scanning electron microscope

• Transmission electron microscopy

• Either scanning or transmission electron microscope

• Compound light microscope

The prefix "micro" refers to tiny, and the suffix "scope" refers to view or look at. Microscopes are tools used to enlarge images of small objects so they can be studied more effectively. There are various types of microscopes, depending on the type of image that the scientist wants to view. 

Therefore if a scientist is attempting to view the external surface of a bacterial cell with an emphasis on surface detail, what statement BEST explains what type of microscope to select in this scenario, with a rationale for using that particular kind of microscope?

• A Scanning Electron Microscope (SEM) because it produces images by scanning specimens with a focused beam of electrons in order to provide a surface image of the organism.

• A Transmission Electron Microscope (SEM) because it produces images by scanning speciements with a focused beam of electrons in order to provide a surface image of the organism.

• A Compound Light Microscope because it produces imaged by scanning specimens with a focused beam of electrons in order to provide a surface image of the organism.

• A Scanning Electron Microscope (SEM) because it produces images by scanning specimens with a focused beam of electrons in order to provide magnified detailed internal images of organelles.