Microscopy
- Created by: Rosyposyxx
- Created on: 08-07-17 22:07
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- Microscopy
- Light Microscope
- The first type of microscope
- Easily available
- Relatively cheap
- Portable, can be used in the field
- Can observe living and dead specimens
- A compound light microscope has two lenses
- An objective lens, placed near the specimen
- Magnification= objective lens x eyepiece lens
- An eyepiece lens, through which the specimen is viewed
- Magnification= objective lens x eyepiece lens
- An eyepiece lens, through which the specimen is viewed
- illumination is usually provided by a light underneath the sample.
- An objective lens, placed near the specimen
- Sample preparation
- Dry mount: solid samples sliced thinly by a sharp blade. Then placed on a slide and covered with a cover slip
- Wet mount: specimens suspended in liquid such as water or oil. A cover slip is placed on top at an angle
- Squash slides: similar to a wet mount
- Smear slides: the edge of a slide is used to smear the sample, creating a thin even coating. a cover slip is placed on top
- Staining
- Crystal violet or methylene blue are positively charged dyes, attracted to negatively charged materials in cytoplasm, and staining cell components
- Nigrosin or congo red are negatively charged and repelled by the negatively charged cytosol. the dyes stay outside, leaving the cells unstained
- Differential staining differentiates between two types or organism or different organelles
- Gram stain technique. separates bacteria into gram positive and gram negative. Use crystal violet dye. gram positive bacteria appear purple. add safranin dye, gram negative bacteria appear red
- Acid fast technique differentiates mycobacterium.
- A microscope is an instrument which enables you to magnify an object thousands of times
- Biological drawings
- Include a title
- State magnification
- Use a sharp pencil
- Use as much space as possible
- draw smooth continuous lines
- Do not shade
- draw clearly defined structures
- Use appropriate proportions
- Don't cross label lines, don't use arrow heads. label lines should be horizontal along the page
- Magnification and resolution
- Magnification is how many times larger the image is than the actual size of the object
- Magnification= objective lens x eyepiece lens
- Image size = magnification x actual size
- Magnification= objective lens x eyepiece lens
- The resolution of a microscope determines the amount of detail that can be seen
- Resolution is the ability to see individual objects as separate entities
- Resolution is limited by the diffraction of light as it passes through samples and lenses.
- Light Microscope
- The first type of microscope
- Easily available
- Relatively cheap
- Portable, can be used in the field
- Can observe living and dead specimens
- A compound light microscope has two lenses
- An objective lens, placed near the specimen
- illumination is usually provided by a light underneath the sample.
- An objective lens, placed near the specimen
- Sample preparation
- Dry mount: solid samples sliced thinly by a sharp blade. Then placed on a slide and covered with a cover slip
- Wet mount: specimens suspended in liquid such as water or oil. A cover slip is placed on top at an angle
- Squash slides: similar to a wet mount
- Smear slides: the edge of a slide is used to smear the sample, creating a thin even coating. a cover slip is placed on top
- Staining
- Crystal violet or methylene blue are positively charged dyes, attracted to negatively charged materials in cytoplasm, and staining cell components
- Nigrosin or congo red are negatively charged and repelled by the negatively charged cytosol. the dyes stay outside, leaving the cells unstained
- Differential staining differentiates between two types or organism or different organelles
- Gram stain technique. separates bacteria into gram positive and gram negative. Use crystal violet dye. gram positive bacteria appear purple. add safranin dye, gram negative bacteria appear red
- Acid fast technique differentiates mycobacterium.
- Diffraction is the tendency of light waves as they pass physical structures. the light reflected can overlap and detail is lost
- Can be increased using electrons, which have a much much smaller wavelength
- Light Microscope
- Magnification is how many times larger the image is than the actual size of the object
- Electron microscopy
- Light Microscope
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