MSBS 5065S: Cellular Structure and Function - Microscopy (Vocabulary Flashcards)

Vocabulary flashcards covering key microscopy concepts from the lecture notes.

Microscopy

The technique of using microscopes to visualize cells and subcellular structures, including light, fluorescence, confocal, and electron microscopy.

Contrast

Difference in image brightness between structures, often enhanced with stains or illumination methods.

Resolution

Ability to distinguish two closely spaced objects as separate; limited by wavelength and numerical aperture, described by Abbe’s equation.

Stain

A dye used to impart color to cellular components to increase image contrast.

Hematoxylin

A basic dye that binds arginine/lysine, staining nuclei blue (basophilic).

Eosin

An acidic dye that stains cytoplasm pink (eosinophilic).

H&E staining

Hematoxylin and Eosin staining of fixed tissue sections to visualize nuclei and cytoplasm.

Fixation

Preservation of tissue structure by cross-linking molecules, enabling long-term storage and analysis.

Permeabilization

Treating cells to perforate membranes so antibodies can access intracellular targets.

Immunohistochemistry

Staining method using antigen-specific antibodies to detect target proteins in tissue sections.

Primary antibody

Antibody that directly binds the target antigen.

Secondary antibody

Antibody that binds to the primary antibody and carries a detectable label.

Antibody probe

Antibody labeled with a fluorescent or enzymatic tag to visualize specific targets.

Molecular Probes

Dyes or molecules that label specific cellular constituents (e.g., mitochondria, nuclei) for imaging.

Vital dye

Dyes that stain living cells without fixation.

Fluorescent dye

Dye that emits light upon excitation, enabling fluorescence imaging.

FITC

Fluorescein isothiocyanate; a green-emitting fluorophore used in immunofluorescence.

Alexa Fluor dyes

A family of bright, photostable fluorophores (e.g., Alexa 488, 555) used for multicolor imaging.

Dichroic mirror

Optical element that reflects excitation light while transmitting emission light in fluorescence microscopes.

GFP

Green Fluorescent Protein from Aequorea victoria; used as a fusion tag to visualize proteins in living cells.

PA-GFP

Photoactivatable GFP; activated by light to enable super-resolution localization imaging.

DsRed

Red fluorescent protein used for multiplex fluorescence imaging.

Brainbow

Genetic approach using multiple fluorescent proteins to label neurons with many colors for circuit mapping.

GFP fusion

Fusion of GFP to a target protein to visualize its localization in living cells without fixation.

In vivo imaging

Imaging within living organisms.

Confocal microscopy

Laser-scanning microscopy with a pinhole to remove out-of-focus light for optical sectioning and 3D reconstruction.

Deconvolution

Computational method to remove out-of-focus blur from fluorescence images.

3D reconstruction

Building a three-dimensional representation from sequential optical sections.

Out-of-focus light

Light from planes above or below the focal plane that degrades image quality.

Abbe’s equation

Resolution = 0.61 × (λ) / NA; defines diffraction-limited resolution based on wavelength and objective NA.

Rayleigh criterion

Two points are just resolvable when the maximum of one point’s image lies beyond the first minimum of the other.

Diffraction limit

Fundamental limit of resolution for light microscopy, around ~200 nm.

Airy disk

The diffraction pattern of a point light source; central bright spot with concentric rings.

Super-resolution

Techniques that surpass the diffraction limit to achieve higher spatial resolution.

PALM

Photoactivated Localization Microscopy; uses photoactivatable fluorophores for high-precision localization.

Photoactivation

Selective activation of fluorescent molecules with light to enable controlled imaging.

Immunofluorescence

Fluorescent labeling of specimens using antibodies to detect specific antigens.

Phase contrast

Microscopy technique converting phase shifts in light into intensity differences for unstained samples.

DIC (Differential Interference Contrast)

Optical method enhancing contrast by exploiting interference of light waves.

Fluorescent protein technology

Engineering and use of fluorescent proteins (e.g., GFP variants) for live-cell imaging.

Electron microscopy

Imaging method using electrons, providing much higher resolution than light microscopy.

Mitochondria

Organelle (~500 nm) often used as an example size near optical resolution limits.