Title: Observing Bacteria and Blood- Lab #1
Purpose: Being able to learn how to correctly use a microscope and the oil immersion lens to be able to see the prepared slides. Also to learn how to prepare my own yogurt and blood slides. Procedure: First, set up the microscope. Clean the ocular lenses and objectives with lens paper. Then pace the prepared e slide on the stage and make adjustments. Turn the rotating nosepiece until the 10x objective is above the ring of light coming through the slide. Move the slide using the X and Y stage knobs until the specimen is within the view. Adjust the focus by looking into the eyepiece and focusing the specimen with the coarse then fine focus knobs. Adjust diaphragm until there is sufficient light passing through the specimen. Do that with the next different prepared slides with 10x and 40x objectives. Place a drop of oil on the slide and rotate the oil immersion objective, 100x, into the oil, then past the oil and back. Use the fine focus to bring the object into focus. Second, find a sealable container made of glass or plastic. Clean the container thoroughly with soap and then rinse the container several times to remove the soap. Place a teaspoon of yogurt in the container. Cover the container and place it in a dark, warm area. Leave the container for 12–24 hours. Take a sample of yogurt from the container and place the sample on a clean slide. Observe the bacteria under the microscope at 10x, 40x, and 100x oil immersion. Setting should be low. Compare your observations of the fresh, live slide to the prepared, stained slide.
Third, poke the inside of your finger with the lancet. Squeeze your finger to place a drop of blood on a clean slide. Drop the blood toward one end of a slide. Tilt the cover slip toward the drop. Lay the cover slip flat across the blood smear.
Bacteria bacillus form
Dots looking more like a shape
Bacteria coccus form
Hard to see
Able to see nucleus near center
Bacteria spirillum form
Tiny black spots
Spiral shaped cells with visible nucleus
Blob, with visible organells
Large pink shape with visible nucleus and organelles
Organelles, nucleus, cell structure and membrane
Many sphere shapes in chains
Penicillum w/ conidia
Green near darker clumps
Fresh yogurt slide
(24 hours incubation)
Hard to see
Lots of tiny cells
A lot of dark cells together
Prepared yogurt slide
Many cells clumped together and streaked lines
Cells clumped together
Moving red cells
Red blood cells clumped together, slow moving
More cells, little white blood cells
Results: I was able to see all the slides using the microscope and immersion oil lens. I saw the different shapes of the bacteria from the prepared slides and my yogurt, blood slides. Questions:
Exercise 1: Viewing Prepared Slides
A. Identify the following parts of the microscope and describe the function of each.
1. Eyepiece: transmits and magnifies the image from the objective lens to your eye.
2. Tube: holds the eyepiece at the proper distance from the objective lens and blocks out stray light.
3. Nosepiece: a rotating mount that holds many objective lenses.
4. Stage: where the specimen rests.
5. Diaphragm or disc apertures: placed in the light path to alter the amount of light reaching the condenser. Varying the amount of light alters the image contrast.
6. Lamp: produces light. Typically, lamps are tungsten-filament light bulbs. For specialized applications, mercury or xenon lamps may be used to produce ultraviolet light. Some microscopes use lasers to scan the specimen.
7. Coarse-focus knob: brings the object into the focal plane of the objective lens.
8. Fine-focus knob: makes fine adjustments to focus the image.
9. Arm: a curved portion that holds all of the...
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