Microscopy Flashcards
What is Brightfield microscopy used for?
Commonly used to visualize amplitude objects and produces an image on a bright background. Different colors interact differently with chromophores, which are pigments that absorb and reflect particular wavelengths of light in parts of the specimen.
Chromophores are often artificially added to the specimen.
How does Darkfield microscopy work?
Blocks most light to the objective lens, showing the object on a dark background. It is useful for live specimens and often creates high contrast, high resolution images without the use of stains.
What is the purpose of Phase-Contrast microscopy?
Uses refraction and interference to create high contrast, high resolution images without needing stains. Mostly used on live specimens, allowing easy observation of organelles in eukaryotic cells and endospores in prokaryotic cells.
What does Differential Interference Contrast (DIC) microscopy do?
Uses interference to enhance contrast between different features of a specimen, producing high contrast images of live organisms with a 3D appearance. Useful in distinguishing between features in live and unstained specimens.
What is the function of Fluorescence microscopy?
Uses fluorescent stains to produce an image, which can identify pathogens, species, living cells from dead, or locations of molecules. It is also used for immunofluorescence.
How does Confocal microscopy work?
Uses a laser to scan z-planes, producing 2D high resolution images at various depths. A computer can turn these images into a 3D image, useful for thick specimens such as biofilms.
What is Two-photon microscopy?
Uses a scanning technique, fluorochromes, and long-wavelength light such as infrared to penetrate deep into thick specimens like biofilms.
What is the purpose of Transmission Electron Microscopy (TEM)?
Uses electron beams that pass through a specimen, useful to observe small, thin species, tissue sections, and subcellular structures.
How does Scanning Electron Microscopy (SEM) work?
Uses electron beams to visualize surfaces, useful to observe 3D surface details.
What is Scanning Tunneling Microscopy (STM)?
A probe is passed horizontally at a constant distance just above the specimen while measuring the intensity of the current. It can map the surface at an atomic level and works best on conducting materials, but can be used on materials like DNA if on a fixed surface.
What does Atomic Force Microscopy (AFM) measure?
Uses a laser focused on a cantilever to measure the bending of a tip or probe passed above the specimen. It measures the height needed to maintain a constant current, useful for observing specimens at an atomic level and more easily used with non-conducting samples.
