Observing Bacteria Essay

1123 Words5 Pages
Observing Bacteria

Kelli Jo Simco
Due: 2/8/13

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
…show more content…
Resolution: The closest two objects can be before they are no longer detected as separate objects. Contrast: The difference in light intensity between the image and the adjacent background relative to the overall background intensity.

C. Describe your observations from the fresh yogurt slide you prepared in Exercise 2.
D. Were there observable differences between your fresh yogurt slide and the prepared yogurt slide? If so, explain.

C&D: Observation of the prepared slide was made easier by the purple staining and the dead bacteria. The observation of the fresh specimen was harder to see in a focused manner because it continued to move. The prepared slide is an obvious Bacillus bacterium. While the fresh sample is harder to focus so it is not as easily observed as Bacillus bacterium. There are more bacteria present in the fresh specimen than in the prepared slide.

E Describe the four main bacterial shapes.
Cocci: a spherically shaped bacterium
Bacillus: a rod shaped bacterium
Spirillum: spirally shaped bacterium
Vibrio: comma or S shaped bacteria

F. What are the common arrangements of bacteria?

Cocci: occurring as a single sphere
Diplococci: occurring as spheres in pairs
Streptococci: chains of linked spheres
Staphylococci: spheres grouped in grape like clusters
Bacillus: a single rod arrangement
Diplobacillus: pairs of rods
Streptobacillus: Chain-linked
Open Document