Microscopy and resolution — In which cell types does an electron microscope reveal greater cellular detail than a light microscope?

Difficulty: Easy

Correct Answer: All of these

Explanation:


Introduction:
Imaging technique determines the level of cellular detail you can resolve. This question tests conceptual understanding of why electron microscopy (EM) outperforms light microscopy (LM) across diverse cell types by achieving much higher resolution and magnification.


Given Data / Assumptions:

  • Cell types considered: animal, bacterial, and protist cells.
  • Comparison between EM and LM in terms of structural detail.


Concept / Approach:
Resolution is the minimum distance at which two points are distinguishable. LM is limited by visible light wavelengths and numerical aperture, while EM uses electron beams with far shorter effective wavelengths, yielding markedly better resolution.


Step-by-Step Solution:

1) Consider animal cells: EM reveals organelle ultrastructure (membranes, ribosomes, cytoskeleton) invisible or indistinct by LM.2) Consider bacterial cells: EM resolves cell walls, membranes, flagellar motors, and ribosome-like granules that LM cannot clearly separate.3) Consider protists: EM details complex cortical structures, cilia/flagella axonemes, and membrane systems beyond LM capability.4) Therefore, EM reveals more detail in all listed cell types.


Verification / Alternative check:
Typical LM resolution is on the order of ~200 nm, whereas transmission EM can reach sub-nanometer scales in favorable conditions, explaining consistent superiority in visible detail across cells.


Why Other Options Are Wrong:

  • Animal/Bacterial/Protist alone: arbitrarily restricts the advantage to one group despite universal physics of resolution.
  • None of these: contradicts fundamental limits of LM and capabilities of EM.


Common Pitfalls:
Confusing contrast with resolution; staining can improve LM contrast, but not surpass the diffraction limit. EM requires vacuum and fixed specimens, but this does not negate its superior resolving power.


Final Answer:
All of these.

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