cgualtieri's blog

Perfect Paragraphs: This project was most useful for me in reading the comments other students wrote on my posts. I realized some aspects of my writing style could improve, and tried to use the feedback to improve my writing style. When the project started I found it difficult to differentiate between my drafts and my perfect paragraphs. As the semester went on, I learned how to edit and refine my draft posts to make them into better paragraphs. This is a skill that I will use in all of my future writing projects, and would not have had learned if it was not for this aspect of the class. I found at times it was difficult to comment on other students posts because I simply could not find anything wrong with their writing. I learned to look deeper into their writing and point out things that would have otherwise went unnoticed if I had not been paying close attention. 

Proposal: This project showed me how important it is to present your idea for a research project in a clear, concise, and appealing manner. When we started this project, I was not that excited about the topic my group had chosen but I gradually warmed up to it when we started putting our proposal together. I realized that even though the topic was not super interesting or novel, it could still be presented in a way that could gain some interest from other students in the class. I thought that writing a proposal would be similar to writing a scientific paper, but it was much much different. It was difficult writing the proposal without knowing if the results that we would collect would be significant enough to make doing the experiment worth it. From this project I learned that even if you do not know what the outcome of your experiment will be, it is still important to be confident in your proposal and provide a concise summary of what you know, and what you hope to find. 

The results from this experiment were not fully in accordance with my expected results. The tubes containing glucose and sucrose turned yellow after incubation, and a bubble of CO2 gas was present in the Durham tube. These results were expected, and showed that S. cerevisiae was able to ferment these two sugars and produces CO2 gas in the process. However, the tube containing lactose was also yellow and contained a bubble in the Durham tube after incubation, which was not expected. This shows that S. cerevisiae is able to ferment lactose along with glucose and sucrose. I did not expect to see this result because lactose is not present in the natural environment of S. cerevisiae. This result could be explained by a gain-of-function mutation in the strain of S. cerevisiae used in this experiment. Another explanation could be that the pH sensitive dye used was too sensitive and turned yellow with only a very small change in the solutions pH.

This experiment showed the ability of S. cerevisiae to ferment three different sugars, lactose, glucose, and sucrose. It was expected that this bacterium would only be able to ferment glucose and sucrose, but my observations revealed that it was able to ferment all three sugars. CO2 gas was observed in all three Durham tubes, and the media in all three tubes changed color from purple to yellow. This clearly showed that S. cerevisiae is able to ferment a variety of sugars, even one that is not present in its natural environment.

The results from this experiment were in accordance with my expected results. When observing the FPDA and PCA plates side by side, there was significantly more penicillium growth on the FPDA agar than the PCA agar. There was growth on approximately 90% of the FPDA plate compared to only about 50% on the PCA plate. The mold on both plates grew outwards in a circular pattern from the point of inoculation with lines radiating outwards from the center. The penicillium on the FPDA plate grew much further away from the center of the agar than it did on the PCA agar. The mold on both plates was green and white colored. The white structures were observed to be hyphae and the green structures were observed to be spores. The penicillium on the FPDA plate was brighter and more vibrantly colored than it was on the PCA plate. The penicillium on the PCA plate was dull and had a brown hue.

In the fungus cultivation portion of this lab, penicillium mold was grown onto two agar plates with variations in nutrient availability. Fresh potato dextrose agar (FPDA) and potato carrot agar (PCA) were the two media used to grow penicillium. FDPA is more nutrient rich than PCA, so it was expected that the penicillium mold would grow better on FPDA compared to PCA. Both plates were inoculated in the center of the agar with a dime sized circle of penicillium and left to incubate.

In conclusion, this experiment was able to obtain CFU/ml values for one dilution of E.

coli. There were approximately 8.9x104 CFU/ml of E. coli in one ml of the 10-2 dilution. This

number was obtained using The 10-1 dilution produced to many colonies to count, making

obtaining a CFU/ml value impossible. The other dilutions did not produce more than 30 colonies,

possibly due to a mistake in the dilution process. Another explanation for this could be that when

the dilutions were prepared, the aliquots may have had a lower CFU/ml than other aliquots by

random chance. This experiment showed that using viable counts is a reliable and effective way

to count the number of bacteria in an inoculated sample.

In the viable counts portion of this lab we used viable counts to observe the number of cells

present on Petri dishes inoculated with decreasing dilutions of E. coli. The E. coli were diluted in

sterile saline and spread at dilutions of 10-1, 10-2, 10-3, 10-4, 10-5, 10-6, 10-7, and 10-8. Dilution and

viable counts is a useful technique because it allows live cells to be counted, eliminating the

variable of dead cells contributing to a cell count. Colony forming units per ml (CFU/ml) were

calculated to determine the number of cells growing at each dilution. I expected the highest

CFU/ml would be from dilutions containing a higher concentration of cells, and the lowest from

the more dilute samples. . I expected that as the solutions increased in dilution, , the CFU/ml

would decrease due to less E. coli being transferred and inoculated onto the Petri dish.

The results of this experiment showed that E. coli grown at 37°C had the highest growth

rate (k), at 1.92 generations/hour and lowest generation time (g) at 31.4 minutes. The E. coli

grown at 27°C had a growth rate of 1.02 generations/hour and a generation time of 59.3 minutes.

At 45°C, the growth rate of E. coli was 0.9 generations/hour and the generation time was 66.6

minutes. The E. coli grown at 55°C did not grow sufficiently enough to calculate k and g values,

due to the high temperatures causing the cells to lyse.

The purpose of the experiment was to determine whether different variables of LED light affected spider behavior and web production. We set up six different enclosed environments: two with two different colored LEDs (red & yellow), two with the LEDs in different locations (top & bottom), and two with the LEDs turned off.  We put one cellar spider and two wooden sticks in each container, and left them in complete darkness under a cardboard box for three days. We measured the distance of the cellar spider from the LED in centimeters, and whether or not there was a web present, then analyzed this data. We observed that the LED light had no effect on web formation, as all of the spiders build their webs with one end attached to the LED bulb. However, the LED light did have an effect on spider behavior, as spiders exposed to LED light remained farther away from the bulb compared to spiders not exposed to light.