Both plant and animal tissue is composed of cells, cells are the basic unit of all life, and cells only develop from existing cells.
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What two leneses are used to magnify an image with a light microscope?
Objective and eyepiece lens.
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What happens during a dry mount preparation?
Solid specimens are viewed whole or cut into very thin sliced using a blade (sectioning). The specimen is placed on the slide and a cover slip is placed over the specimen.
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What happens during a wet mount preparation?
Specimens are suspended in a liquid such as water or an immersion oil. A cover slip is placed on from an angle.
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What happens during preparation involving squash slides?
A wet mount is first prepared, then a lens tissue is used to gently press down the cover slip. Depending on the material, potential damage to a cover slip can be avoided by squashing the sample between two microscope slides
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What happens during preparation involving smearing slides?
the edge of a slide is used to smear the sample, creating a thin, even coating on another slide. A cover slip is then placed over the sample.
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Why are stains used during microscopy?
They increase contrast and an increase in contrast allows components to become visible.
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Name a positively charged dye that stains cell components.
Methylene blue
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Name a negatively charged dye that stains the background.
Congo red
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Why is a gram stain technique used?
It's used to separate bacteria into two groups- Gram-positive (appear blue/purple) and Gram-negative (appear red).
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Why is the acid-fast technique used?
It is used to differentiate species of Mycobacterium from other bacteria.
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What four stages are involved in microscopy preparation?
Fixing, sectioning, staining, and mounting.
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What is the definition of magnification?
How many times larger the image is than the actual size of the object being viewed.
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What is the definition of resolution?
The ability to see individual objects as separate entities.
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What is resolution limited by?
Diffraction
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How can resolution be increased?
By using beams of electrons which have a wavelength thousands of times shorter than light.
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How does a transmission electron microscope work?
A beam of electrons is transmitted through a specimen and focused to produce an image.
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How does a scanning electron microscope work?
A beam of electrons is sent across the surface of a specimen and the reflected electrons are collected.
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What is the maximum magnification and resolution of a light microscope?
Up to x2000 and 200nm
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What is the maximum magnification and resolution of a TEM?
Up to x500,000 and 1nm
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What is the maximum magnification and resolution of a SEM?
Up to x100,000 and 10nm
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What microscope has the shortest wavelength?
TEM
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Which microscope doesn't show false colour?
Light microscope
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Which microscope preparation involves staining?
Light microscope
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Why is there a vacuum inside an electron microscope?
To ensure the electron beams travel in straight lines.
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What is an artefact?
An artefact is a visible structural detail caused by processing the specimen and not a feature of the specimen
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Other cards in this set
Card 2
Front
What two leneses are used to magnify an image with a light microscope?
Back
Objective and eyepiece lens.
Card 3
Front
What happens during a dry mount preparation?
Back
Card 4
Front
What happens during a wet mount preparation?
Back
Card 5
Front
What happens during preparation involving squash slides?
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