Microscopy and Imaging Techniques Flashcards

What is a 'wet mount' preparation in light microscopy?

Answer: A specimen suspended in a drop of liquid between a slide and coverslip

A wet mount places a specimen in a drop of water or buffer covered by a coverslip, allowing observation of live or unstained specimens.

What does SEM (Scanning Electron Microscopy) primarily image?

Answer: The surface topography of specimens

SEM scans a focused electron beam over the specimen surface, detecting secondary electrons to create three-dimensional surface images.

Which objective lens would provide the greatest working distance from the lens to the specimen?

Answer: 4x (scanning objective)

Lower magnification objectives like the 4x scanning objective have the greatest working distance, while higher magnification objectives are much closer to the specimen.

In fluorescence microscopy, what does a fluorophore do when excited by light of the correct wavelength?

Answer: It absorbs the excitation light and emits light at a longer wavelength

A fluorophore absorbs photons at its excitation wavelength and re-emits photons at a longer (lower energy) emission wavelength, a process called fluorescence.

What is the correct order of steps when beginning microscopy observation of a new slide?

Answer: Place slide → use lowest power objective → focus with coarse adjustment → switch to higher power using fine adjustment only

Always start with the lowest power objective to locate the specimen and achieve initial focus before progressing to higher magnification objectives.

Which type of microscopy is best suited for creating three-dimensional reconstructions of thick fluorescent specimens?

Answer: Confocal laser scanning microscopy

Confocal microscopy acquires serial optical sections through the specimen that can be digitally stacked to reconstruct three-dimensional structures.