Abstract/Summary: Changing our focus from the properties and functions that take place within the cell to the actual cell itself, we observed three specific bacterial types within this lab: Gram-positive bacteria, Gram-negative bacteria, and cyanobacteria. We closely observed the features of cyanobacteria and were able to differentiate them from other bacteria. We specifically observed gloeocapsa, merismopedia, anabaena, and oscillatoria. In addition to this we observed the different characteristics of prokaryotic organisms referring to size, form, color, elevation and texture, which helped us to understand the diversity of these cell types in the kingdom Monera. Through ...view middle of the document...
We will also examine the characteristics of these prokaryotic organisms such as the visible size, form, color, elevation, and texture of a colony or colonies. To get detailed observations of these various organisms we will view their occurrence through the culturing of samples by adding microbes onto a sterile medium within Petri dishes and allowing them to multiply. Finally we will also examine the features of cyanobacteria that distinguish them from other bacteria, and their role in nature.
Materials/Methods: First examine the plates prepared in the previous week and observe as many of your other classmates plates as possible. While observing keep in mind the number of organisms or colonies formed as well as the types of organisms. Also note the number of different colony types based in colony size, shape, color, elevation, and texture. Move on to the second part of the procedure involving Gram staining. First wash a microscope slide with soap and water and dip the slide in alcohol and allow to air dry. Put two drops of deionized water on the slide. Flame a bacterial loop to kill any foreign organisms then use it to scoop a small portion of the bacterial colony off the agar plate and spread it evenly on the slide’s center. Resterilize the loop. Allow the slide to air dry. Using a clothespin, gently heat the slide passing it three times through low flames to allow the cells to adhere to the surface. After it is cooled flood the surface with Gram’s stain. After waiting a minute rinse off the stain with water.
Now flood the slide with aqueous iodine to enhance color development, then rinse the slide with water again after waiting another minute. Squirt 95 percent ethanol over the surface of the stained slide carefully until the runoff is clear. Rinse with water. Now flood the surface with safranin, a counterstain. After waiting a minute carefully rinse your slide with water. Blot the edges of your slide dry with a paper towel and examine under oil immersion. Record your observations and make a sketch. If time permits examine your own oral bacteria. Scrape the tartar between your teeth and smeer it on a slide and heat the slide to promote adhering. Add a drop of crystal violet stain and wash off with water after a minute then blot the slide edges dry. Allow your slide to air dry and then examine under oil immersion and sketch your observations. For the third portion of our experiment we will observe cyanobacteria. Prepare a wet mount of Gloecapsa. Then place a drop of India ink to one side of the coverslip and promote diffusion by placing absorbent tissue on the opposite side of the coverslip. Describe the color by shade distribution and comment whether it is localized evenly spread throughout the cell.
Prepare a wet mount of Merismopedia. Look for the dividing cell and describe the division process. Now prepare a wet mount of Anabaena and apply India ink as in step 1.
Try to identify the Heterocyst and Akinete. Do you observe nuclei?...