2.1-2.3 Microscopy Flashcards
What is the main difference between light microscopes and electron microscopes?
Light microscopes use light to illuminate specimens and can magnify up to about 2000x, while electron microscopes use electron beams, achieving magnifications up to 2 million times and providing higher resolution.
Describe the basic components of a light microscope.
A light microscope includes an eyepiece, objective lenses, a stage, a light source, and focus knobs (coarse and fine).
What is the role of the condenser lens in a light microscope?
The condenser lens focuses light onto the specimen to enhance illumination and contrast.
How is the total magnification calculated in a light microscope?
Total magnification = magnification of the eyepiece × magnification of the objective lens.
Describe the structure of a transmission electron microscope (TEM).
TEM uses a beam of electrons transmitted through a thin specimen, producing high-resolution images of internal structures.
What is the main use of scanning electron microscopes (SEM)?
SEM is used to create 3D images of the surface of specimens by scanning the surface with a focused electron beam.
What are some common types of stains used in microscopy?
Common stains include methylene blue, Gram stain, and eosin, each highlighting different cellular components.
What is the purpose of the immersion oil in microscopy?
Immersion oil increases the resolution by reducing light refraction between the lens and the specimen at high magnifications.
What is a biological sample preparation technique for microscopy?
Techniques include sectioning, staining, mounting, and using coverslips to preserve and prepare specimens for observation.
Describe the process of preparing a wet mount.
A wet mount involves placing a specimen in a drop of liquid (usually water), covering it with a coverslip, and observing under the microscope.
What is a histological slide?
A histological slide is a prepared microscope slide that contains a thin section of tissue, often stained to highlight specific features.
How does a fluorescence microscope work?
A fluorescence microscope uses high-energy light to excite fluorescent dyes attached to specific structures, allowing visualization of these components in color.
What are artefacts in microscopy?
Artefacts are structures or features that are not present in the original specimen but appear due to the preparation process or imaging techniques.
Why is it important to calibrate a microscope?
Calibration ensures accurate measurements and helps to correlate the observed magnification with the actual size of the specimen.
What is the role of the mechanical stage on a microscope?
The mechanical stage allows for precise movement of the slide, enabling better focusing and positioning of the specimen.
