OBSERVING BACTERIA

1135 WORDS

Abstract: Microscopes are fragile instruments that must be handle with extreme caution as they can produce high quality results when observing the smallest specimens on earth. A microscope must be properly cleaned before use and storage. The different objectives allow for a range of observations. At the highest objectives, the resolution can easily be lost which is why the oil immersion lens is used to minimize refraction. While observing specimens, both dead and active, their shapes and arrangements can be observed. For example, the oil immersion lens can be used to observe the active Streptobacillus bacteria in yogurt.

Purpose: The purpose of this lab was to display knowledge of the use of a compound microscope with and without an oil immersion lens while observing and identifying various bacterial shapes and arrangements, including a self prepared yogurt culture.

Procedure:

Exercise 1: Viewing Prepared Slides

1. After setting up and cleaning all lenses, place the prepared e slide properly on the stage.

2. View the slide under the10x objective by moving it around with the X and Y stage travel knobs then focus it by first using the coarse adjustment followed by the fine adjustment until the view is clear.

3. Adjust the diaphragm to allow enough light for good resolution.

4. After a micrograph is taken, rotate the 10x objective away from the specimen and the 40x over it. Use the fine adjustment knob to bring the specimen back into focus.

5. Repeat the above steps for 6 more specimens. Those viewed and micrographed in this lab are:

Amoeba