Microscopy short answer type questions for B.Sc Botany 5th semester

Principles of Microscopy; Light Microscopy; and Fluorescence Microscopy (SAT)

1. What is microscopy?

Ans: Microscopy is the technique of using instruments to view objects too small for the naked eye.

2. How does light microscopy work?

Ans: Light microscopy uses visible light to illuminate specimens and magnify them for observation.

3. What is the principle of fluorescence microscopy?

Ans: Fluorescence microscopy uses fluorophores to emit light of a specific wavelength when excited by light of another wavelength.

4. How does a compound microscope function?

Ans: A compound microscope uses two sets of lenses to magnify the specimen.

5. What is the resolving power of a microscope?

Ans: Resolving power is the ability to distinguish two adjacent points as separate entities.

6. How does phase contrast microscopy enhance visibility?

Ans: Phase contrast microscopy converts phase differences in light waves passing through the specimen into contrast.

7. What is the numerical aperture (NA) in microscopy?

Ans: Numerical aperture determines the light-gathering capacity of an objective lens.

8. What is the purpose of immersion oil?

Ans: Immersion oil increases numerical aperture and resolution in oil immersion microscopy.

9. How does dark-field microscopy visualize unstained specimens?

Ans: Dark-field microscopy illuminates specimens at an oblique angle, causing them to scatter light and appear bright against a dark background.

10. What does differential interference contrast (DIC) microscopy reveal?

Ans: DIC microscopy enhances contrast by detecting variations in specimen thickness.

11. What is confocal microscopy?

Ans: Confocal microscopy uses a pinhole to eliminate out-of-focus light, producing clearer images.

12. How does fluorescence microscopy label specific structures?

Ans: Fluorescent dyes or markers selectively label cellular structures for visualization.

13. What is the advantage of confocal microscopy in live-cell imaging?

Ans: Confocal microscopy minimizes photodamage during live-cell imaging.

14. What are the different types of fluorescence microscopy?

Ans: Fluorescence microscopy includes wide-field, confocal, TIRF, and super-resolution techniques.

15. How does TIRF microscopy work?

Ans: Total Internal Reflection Fluorescence microscopy selectively illuminates the specimen's surface for high-resolution imaging.

16. What are the applications of super-resolution microscopy?

Ans: Super-resolution microscopy is used for nanoscale imaging and single-molecule studies.

17. What is the main limitation of conventional light microscopy?

Ans: Conventional light microscopy is limited by the diffraction of light.

18. What does the Köhler illumination method do?

Ans: Köhler illumination ensures even illumination and contrast throughout the field of view.

19. How does a fluorescent dye emit light in fluorescence microscopy?

Ans: A fluorescent dye absorbs light energy and emits it at a longer wavelength.

20. What are the advantages of using fluorescent proteins in microscopy?

Ans: Fluorescent proteins are genetically encoded markers that label specific structures in living cells.

21. What is the purpose of a dichroic mirror?

Ans: A dichroic mirror reflects excitation light to the specimen while transmitting emitted fluorescence to the detector.

22. What is time-lapse imaging used for in cell biology?

Ans: Time-lapse imaging captures dynamic processes and changes in real-time.

23. How does electron microscopy differ from light microscopy?

Ans: Electron microscopy uses electrons instead of light to achieve higher resolution.

24. What are the two main types of electron microscopy?

Ans: The two types are transmission electron microscopy (TEM) and scanning electron microscopy (SEM).

25. What is cryo-electron microscopy used for?

Ans: Cryo-EM is used to study proteins and macromolecular complexes at near-native states.

26. How does scanning probe microscopy work?

Ans: Scanning probe microscopy uses a sharp tip to scan surfaces, detecting interactions at the nanoscale.

27. What are the applications of atomic force microscopy (AFM)?

Ans: AFM is used for surface imaging and force measurements at the nanoscale.

28. What is the primary advantage of near-field scanning optical microscopy (NSOM)?

Ans: NSOM achieves super-resolution imaging using a nanoscale aperture.

29. What is FRET microscopy used for?

Ans: FRET microscopy studies molecular interactions and distances within cells.

30. How does fluorescence in situ hybridization (FISH) work?

Ans: FISH detects and localizes specific DNA or RNA sequences in cells or tissues.

31. What is the primary use of multi-photon microscopy?

Ans: Multi-photon microscopy is used for deep tissue imaging.

32. How does spinning disk confocal microscopy benefit live-cell imaging?

Ans: Spinning disk confocal microscopy minimizes phototoxicity during live-cell imaging.

33. What does Z-stack imaging accomplish in confocal microscopy?

Ans: Z-stack imaging creates 3D reconstructions of specimens.

34. What is the working principle of bright-field microscopy?

Ans: Bright-field microscopy uses transmitted light, creating a dark image on a bright background.

35. What are the advantages of fluorescence lifetime imaging microscopy (FLIM)?

Ans: FLIM provides information about the local environment and interactions of fluorescent molecules.

36. What does structured illumination microscopy (SIM) improve?

Ans: SIM improves the resolution beyond the diffraction limit of light.

37. What is the purpose of deconvolution in microscopy?

Ans: Deconvolution enhances the

 resolution and contrast of images.

38. What are the limitations of super-resolution microscopy?

Ans: Super-resolution microscopy requires specialized equipment and fluorophores.

39. How does light sheet fluorescence microscopy (LSFM) benefit imaging of thick specimens?

Ans: LSFM minimizes photodamage and provides high-resolution imaging in thick specimens.

40. What is the function of the objective lens in fluorescence microscopy?

Ans: The objective lens collects and focuses light from the specimen.

41. How does a transmission electron microscope visualize internal structures?

Ans: TEM passes a beam of electrons through the specimen to create detailed internal images.

42. What is the primary advantage of scanning electron microscopy (SEM)?

Ans: SEM provides high-resolution images of surface morphology.

43. What is the use of gold nanoparticles in microscopy?

Ans: Gold nanoparticles serve as contrast agents in electron microscopy.

44. What is the primary difference between wide-field and confocal microscopy?

Ans: Confocal microscopy eliminates out-of-focus light, improving image clarity.

45. What is the role of an ocular lens in microscopy?

Ans: The ocular lens magnifies the image formed by the objective lens.

46. What are the applications of dark-field microscopy?

Ans: Dark-field microscopy is used for observing unstained or transparent specimens.

47. How does bright-field microscopy create contrast?

Ans: Bright-field microscopy relies on differences in specimen absorption to produce contrast.

48. What is the benefit of using a scanning tunneling microscope (STM)?

Ans: STM achieves atomic-level resolution for surface imaging.

49. What are the primary advantages of using a fluorescence microscope over bright-field microscopy?

Ans: Fluorescence microscopy provides high sensitivity and specific labeling of cellular structures.

50. How does phase contrast microscopy enhance the visualization of cellular structures?

Ans: Phase contrast microscopy converts phase differences in light waves passing through the specimen into contrast, making transparent structures visible.