Matric's card no.:111431
Lab 1: Principles and use of microscope
1.1 Setting up and using the microscope
Introduction
In order to
be seen, microorganisms need to be magnified. Despite advances in other area of
microscopy ( for example, the electron microscope ), the light microscope is
still the instrument most frequently used for viewing microorganisms.
The function
of any microscope is to enhance resolution. The microscope is used to create an
enlarged view of an object such that we can observe details not otherwise
possible with human eye. Because of the enlargement, resolution is often
confused with magnification, which refers to the size of an image. In general,
the greater the magnification, the greater the resolution , but this is not
always true. There are several practical limitations of lens design which can
result in increased magnification without increased resolution.
The total magnification of the image seen is
calculated by the following formula:
Total
Magnifications= Objective Lens Power × Eyepiece Lens Power
Objective
Learn to use a simple bright – field microscope
correctly.
Results
Stained
cells under magnification of (40 x, 100 x, 400 x).
1.) Salmonella enteritidis under 40x magnification
1.) Salmonella enteritidis under 40x magnification
2.)
Salmonella
enteritidis under 100x magnification
Discussions
1.) The specimen was observed using the lowest magnification which is 40x to the 400x.
2.) While observing the images, fine adjustment knob is used first followed by the coarse adjustment knob to ensure that the image is clear and focused at the centre.
3.) Light intensity is adjusted to enable the correct amount of light enters the microscope and diaphragm is also adjusted to have a clearer view of the specimen.
4.) The microorganism that was observed and drawn is Salmonella enteritidis.
5.) The properties of the Salmonella enteritidis:
1.) The specimen was observed using the lowest magnification which is 40x to the 400x.
2.) While observing the images, fine adjustment knob is used first followed by the coarse adjustment knob to ensure that the image is clear and focused at the centre.
3.) Light intensity is adjusted to enable the correct amount of light enters the microscope and diaphragm is also adjusted to have a clearer view of the specimen.
4.) The microorganism that was observed and drawn is Salmonella enteritidis.
5.) The properties of the Salmonella enteritidis:
-Shape: Rod form
-Size: Tiny
-Surface: Shinny
-Texture: Smooth
-Color: Red
Conclusion
References
http://bioweb.uwlax.edu/bio203/s2009/meinhard_jaso/Adaptation_.htm
1.2 Examination of cells
Introduction
Because of their extreme minuteness, bacteria are not
generally studied with the low-power or high power dry objectives. Instead they
are stained and observed with the oil immersion objective.
The wet mount
methods enables you to study the sizes and shapes of living microorganisms (drying
or staining microorganism distort them). It also enables you to determine if
cells are motile. The wet mount method is quick and easy, and does not require
special equipment.
Objective
-To provide an experience in the use of microscope.
-To illustrate the diversity of cells and microorganisms.
Results:
Lactobacillus fermentum (1000x magnification)
Yeast (Saccharomyces
cerevisiae) (1000x magnification)
Discussions
1.) The oil immersion fills the space between the objective lens and specimen and matches the refractive index of the glass coverslip and glass objective lens. At a given focal length, this allows me to achieve a greater numerical aperture.
2.) The microorganisms that i observed in this experiment were Lactobacillus fermentum and Saccharomyces cerevisiae.
3.) The morphology of Lactobacillus fermentum :
1.) The oil immersion fills the space between the objective lens and specimen and matches the refractive index of the glass coverslip and glass objective lens. At a given focal length, this allows me to achieve a greater numerical aperture.
2.) The microorganisms that i observed in this experiment were Lactobacillus fermentum and Saccharomyces cerevisiae.
3.) The morphology of Lactobacillus fermentum :
-Shape: Rod
-Size: Tiny
-Surface: Smooth
-Texture: Moist
-Color: Violet
4.) The morphology of Saccharomyces cerevisiae :
4.) The morphology of Saccharomyces cerevisiae :
-Shape: Circular
-Size: Tiny
-Surface: Smooth
-Texture: Moist
-Color: Lemon yellow
Conclusion
As a conclusion, i could get a clear view on the morphology of the microorganisms like Lactobacillus fermentum and Saccharomyces cerevisiae in this experiment by using immersion oil which could ensure magnification of 1000x achieved while still preserving good resolution.
References
http://bioweb.uwlax.edu/bio203/s2007/nelson_andr/
wiki.answers.com/Q/why-is-oil-necessary-when-using-the-90x-to100x-objective
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