BIO1011 Lecture Notes - Lecture 3: Confocal Microscopy, Phase-Contrast Microscopy, Scanning Electron Microscope
Microscopy
•There are two key properties of a microscope.
-Magnification - enlarging the image
-Resolution - ability to see fine detail
Types of Microscopes
•Light microscopy:
•allows us to magnify cells up to 1000 times and to resolve details as small as
0.2um.
•Light microscopy allows us to see cells of 400- 700 um.
•If a cell is 100um will be unable to see the organelles, due the to the resolution
being unable to work, even if you can keep magnifying.
•A bright light must be focused onto the specimen by lenses in the condenser.
•The specimen must be carefully prepared to allow light to go through it.
•Phase contrast microscopy:
•Uses a light microscope with an optical component to take advantage of the
different refractive indexes of light passing through different regions of the
cell.
•Bright-field:
•Employs a light microscope and requires that samples be fixed and stained
in order to reveal cellular details.
•Fluorescence microscopy:
•Fluorescent dyes or probes used for staining cells are detected with the aid of a
fluorescence microscope.
•This is similar to light microscope except that the illuminating light is passed through
two sets of filters.
•Confocal microscopy:
•A specialized type of fluorescence microscope that builds up an image by
scanning the specimen with a laser beam.
•Electron microscopy:
•Rather than using light, electrons are used
•There is much greater resolution and magnification than light microscopes.
•There is a better level of resolution because the wave lengths involved are shorter
than used in light microscopy.
•Electron microscope images are not in colour
Document Summary
Microscopy: there are two key properties of a microscope. Resolution - ability to see ne detail. Types of microscopes: light microscopy, allows us to magnify cells up to 1000 times and to resolve details as small as. Another antibody with a probe is attached to locate the original: can record in live time, scanning electron microscopy, the same as transmission electron microscopy however, there is a video screen attached, resulting in 3d images. Model species: all cells are thought to be descended from a common ancestor, whose fundamental properties have been conserved through evolution, therefore, knowledge gained from the study of one organism contributes to our understanding of others. Arabidopsis: has been chosen as a model plant, arabidopsis thaliana, studying this simple weed provides insights into the development and physiology of the crop plants as well as the evolution of other plant species.
