Cytoplasm, Aliens, Gram Staining and More

by on January 31st, 2011
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1) My least favorite organism was Ebola for obvious reasons, but dust mites are my Ebola, since Wisconsin doesn’t really provide a vector for Ebola. I haven’t had an opportunity to use some of those microscopes presented. The interactive animation of the cell was good, better than what I’ve had before.
The second site interested me because electron microscopy is not something a lower-level student gets to do everyday. My work has an SEM, but I haven’t had the chance to use it yet. The diagrams for making the SEM is a bit complicated, but the pictures are easy to understand!
2) The medium must be acidic. Assuming one is referring to H. pylori, the medium would best be defined as a combination of egg yolk emulsion agar and chocolate agar, according to Piccolomini et al. (“Optimal combination of media for primary isolation of Helicobacter pylori from gastric biopsy specimens” J Clin Microbiol. 1997 June; 35(6): 1541-1544).
3) Agar would be ideal for determining if a bacterium is resistant to a particular antibacterial. First, one would practice aseptic techniques to inoculate a selective medium and incubate it. Then one would verify the organism via microscopy. Then, an antibacterial disk can be placed on agar and be observed longitudinally to see if there is a clear halo around the antibacterial disk.
Chapter 4
Cytoplasm provides fluidity for movement and space for materials to transfer through. The cell membrane provides a medium for import and export, whether it uses ATP or not depends on the substance. A chromosome is needed to reproduce. Ribosomes provide the building blocks for growth and repair. In summary, the basis of a cell is to eat, move, reproduce, and grow. So why do cells have more structures? Theoretically, a human could survive without appendages, but it would make life more difficult. The additions to the cell allow it to grow better, thus increasing its chance of survival. This correlates to cilia and flagellum in the cell model. Certain organelles, like chloroplasts, are only needed if the cell is photosynthetic.

Most assuredly there is microbial life on other planets. Within our solar system, however; it is doubtful. None of our eight planets except Earth has a complete atmosphere, which means they are unprotected from the suns UV rays which mutate DNA. When kids get a mole on their skin from the sun, it is because the UV rays mutate your skin’s DNA. In addition, every bacterium must have a food source. Not many food sources can live in extreme temperatures, high pressure, and no oxygen. Some bacteria can live without oxygen however, and they are called anaerobic. These bacteria are the most likely candidates for interstellar bacteria.

The gram stain is used to differentiate between organisms that have a thick peptidoglycan cell wall (Gram +, purple) or a thinner cell wall (-, pink). The process takes advantage of a cell’s ability to become dehydrated and lose cell wall volume. The medical application of a Gram stain involves the severity (negative organisms tend to be more pathogenic). In addition, it helps to further identify an organism so a specific antibiotic for the suspected pathogen can be used.


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