Light Microscopy Techniques for Cell Visualization

Light Microscope

Instrument for viewing small objects using light.

Plant Cell

Cell type with rigid cell wall and chloroplasts.

Animal Cell

Cell type lacking cell wall, more flexible structure.

Bacterium

Single-celled organism, prokaryotic structure.

Virus

Infectious agent, requires host to replicate.

Ribosome

Cellular structure for protein synthesis.

Globular Protein

Protein with a compact, spherical shape.

Cell Wall

Rigid outer layer of plant cells.

Chloroplast

Organelle for photosynthesis in plant cells.

Prokaryotic Cell

Cell without a nucleus, simpler structure.

Eukaryotic Cell

Cell with a defined nucleus and organelles.

Microscopy

Technique for magnifying small objects.

Resolution

Ability to distinguish two close objects clearly.

Magnification

Increase in apparent size of an object.

Staining

Technique to enhance visibility of cell structures.

Cytoplasm

Gel-like substance within a cell.

Nucleus

Control center of eukaryotic cells.

Cell Membrane

Barrier that controls entry and exit of substances.

Organelles

Specialized structures within a cell.

Cell Theory

Fundamental concept that all living things are composed of cells.

Cell Division

Process by which a cell splits into two.

Tissue

Group of similar cells performing a specific function.

Organ

Structure composed of different tissues working together.

Bacteria

Smallest discernible objects in light microscopy.

Mitochondria

Cellular organelles about 500 nm wide.

Wave Nature of Light

Light behaves as waves, affecting image clarity.

Optical Diffraction

Bending of light waves around edges of objects.

Interference Effects

Light waves combine, altering brightness and clarity.

In Phase Waves

Waves reinforcing each other, increasing brightness.

Out of Phase Waves

Waves canceling each other, reducing brightness.

Limit of Resolution

Smallest distance at which two objects appear distinct.

Wavelength of Light

Distance between successive peaks of light waves.

Numerical Aperture

Measure of lens system's light-gathering ability.

Entry Pupil Width

Diameter of lens opening in a microscope.

Violet Light

Light with a wavelength of approximately 400 nm.

Micrometer (µm)

Unit of length equal to 10^-6 meters.

Nanometer (nm)

Unit of length equal to 10^-9 meters.

Angstrom Unit (Å)

Unit of length equal to 10^-10 meters.

Condenser Lens

Focuses light onto the specimen in microscopy.

Objective Lens

Lens that magnifies the specimen image.

Eyepiece Lens

Lens through which the viewer observes the image.

Fringes

Patterns created by interference of light waves.

Circular Pattern

Diffraction pattern from a point light source.

Dark Ring

Area in diffraction pattern indicating resolution limit.

High Magnification

Increased enlargement of an object for detailed viewing.

Detection

Ability to observe objects below resolution limit.

Fluorescently labeled microtubule

Thin structures visible despite resolution limitations.

Diffraction effects

Causes blurring in observed microscopic images.

Angular resolution

Minimum angle between two distinguishable points.

Cone of illumination

Shape of light rays collected by lenses.

Numerical aperture (NA)

Lens's light-collecting ability, affects resolution.

Refractive index (n)

Measure of light bending in different media.

Wavelength of light (λ)

Distance between successive peaks of light waves.

Working distance

Distance between lens and specimen for focusing.

Depth of field

Thickness of specimen plane in focus.

Phase-contrast microscope

Enhances contrast in transparent specimens using phase shifts.

Differential-interference-contrast microscope

Uses interference to visualize living cell structures.

Dark-field microscope

Illuminates specimen from the side, enhancing visibility.

Brightness in microscopy

Importance of light intensity for clear imaging.

Living cell observation

Studying cells without fixation or freezing.

Fluorescence microscopy

Uses emitted light from fluorescent labels for imaging.

Specimen preparation

Process that may distort or lose cell components.

Light scattering

Process used to visualize features of living cells.

Image blurring

Result of diffraction and resolution limits.

Dark-field microscopy

Illuminates cells from the side, creating bright objects.

Bright-field microscopy

Forms images by direct light passing through cells.

Phase-contrast microscopy

Enhances phase differences to visualize transparent cells.

Differential-interference-contrast microscopy

Uses interference effects to visualize cell structures.

Time-lapse movies

Records frames over time to speed up events.

Digital imaging systems

Use electronic techniques for enhanced microscopy.

Charge-coupled device (CCD)

Sensitive camera technology for low-light imaging.

Image processing

Enhances and analyzes images for better clarity.

Optical faults

Imperfections in microscopes affecting image quality.

Low-light conditions

Environments where light levels are insufficient for visibility.

Fluorescent molecules

Substances that emit light when excited by radiation.

Image digitization

Converts images into electronic format for processing.

Contrast enhancement

Improves visibility of small differences in images.

Random background irregularities

Unwanted variations affecting image clarity.

Digital subtraction

Removes background defects from images.

Microtubules

Cytoskeletal structures with a diameter of 0.025 µm.

Cell migration

Movement of cells from one location to another.

Mitosis

Process of cell division resulting in two daughter cells.

Optical components

Parts of a microscope that manipulate light.

Image noise

Unwanted random variations in image data.

High contrast

Significant difference in light intensity for visibility.

Stained cells

Cells treated with dyes to enhance visibility.

Living cells

Cells that are actively functioning and not fixed.

Fixation

Process to preserve and immobilize tissue samples.

Common Fixatives

Substances like formaldehyde used for tissue preservation.

Cross-linking

Formation of covalent bonds to stabilize proteins.

Embedding Media

Waxes or resins used to support tissue during sectioning.

Microtome

Device for cutting thin sections of tissue.

Section Thickness

Typical thickness of sections is 1-10 micrometers.

Hematoxylin

Dye that stains DNA and acidic proteins blue.

In Situ Hybridization

Technique to visualize RNA distribution in tissues.

Fluorescent Probes

Markers used to localize specific proteins in cells.

Histology

Study of microscopic structure of tissues.

Eosin

Dye that stains cytoplasm and extracellular matrix pink.

Safranin

Dye that stains lignified cell walls red.

Fast Green

Dye that stains cellulosic cell walls green.