Microscopy and Cell Biology Concepts

Vocabulary flashcards based on the lecture transcript covering various microscopy types, specimen preparation techniques, magnification, and resolution.

Microscope

Any instrument which magnifies a small object to make it visible.

Compound microscope

A microscope that utilizes two lenses to magnify an image: an objective lens and an eyepiece lens.

Bruno Ferkhoff

A researcher who compared cell appearance in healthy versus diseased patients to relate cellular behavior to the patient's clinical presentation.

Logarithmic scale

A scale where each step is a factor of $10$ greater than the previous one, used to express very large or very small orders of magnitude.

Standard form

A system using indices to express very large or very small numbers as a value multiplied by a power of $10$.

Magnification

The size relationship between an image and an object, calculated as the size of the image divided by the size of the object.

Resolution

The ability to distinguish between two points that are close together as separate objects.

Resolution of the human eye

Approximately $200\,\mu\text{m}$.

Light microscope

A microscope using visible light to illuminate a specimen, reaching a maximum magnification of about $1500\times$ and a resolution limit of about $200\,\text{nm}$.

Methylene blue

A stain or dye that preferentially binds to \text{DNA}, allowing its visualization under a light microscope.

Gram stain

A staining procedure that gets trapped in the cell wall of Gram-positive bacteria (making them dark purple) but does not get trapped in Gram-negative bacteria.

Dry mount

A slide preparation method used for non-aqueous specimens such as flower petals, pollen, or grains of sand.

Fixing

A sample preparation process that prevents sample degradation, kills microorganisms, and maintains the structural integrity of cellular components.

Formaldehyde

A fixative agent that forms chemical cross-links between proteins and lipids in a specimen to prevent bacterial decay.

70% ethanol

A fixative solution used to carefully dehydrate a biological sample, killing microorganisms while retaining cell integrity.

Sectioning

The process of cutting biological tissue into extremely thin slices using a precise tool known as a microtome.

Microtome

A highly precise instrument used to cut extremely thin tissue sections for microscopy.

Confocal fluorescence microscopy

A light microscopy technique that focuses narrow wavelengths of visible light through a pinhole, eliminating out-of-focus background noise to generate higher-resolution images.

Scanning electron microscopy (SEM)

An electron microscopy technique that fires an electron beam across a heavy metal-coated (e.g., gold) sample surface to generate 3D-like images with up to $300{,}000\times$ magnification and $0.5\,\text{nm}$ resolution.

Transmission electron microscopy (TEM)

An electron microscopy technique that passes electrons through ultrathin sample sections to generate high-resolution 2D cross-sectional images.

Ultramicotomy

An extremely precise sectioning method used to produce sample slices less than $150\,\text{nm}$ thick for transmission electron microscopy.

Angstrom

A unit of measure equal to $0.1\,\text{nm}$ ($10^{-10}\,\text{m}$), useful for examining detail at the scale of atoms and atomic bonds.

Graphene

A material composed of a single layer of carbon atoms covalently bonded to three other carbon atoms with delocalized electrons.