Perfect Paragraph

The reaction of plants to stress from their environment, be it the plant’s consumers or the environment, involves a series of pathways which induce defenses (Tian, Peiffer, et al.). These pathways involve several hormones which trigger defense responses in plants. Jasmonic acid is a hormone that plants release to control responses from stress, such as damage from weather or herbivores. It has been observed that applying jasmonic acid onto a tomato plant can be used as a pesticide by inducing defenses plants use naturally to deter herbivores from consuming them (Tian, Tooker, et al.; Tian, Peiffer, et al.). Administering jasmonic acid onto a tomato plant can cause plants to grow more trichomes (hair-like structures that grow on the leaf of the plant that make traversing them more difficult for herbivores) (Tian, Tooker, et al.). Tomato plants treated with jasmonic acid have been shown to be less preferable to consume by herbivores as a result of secondary compounds produced, and the herbivores that consume them do not grow as large (Tian, Peiffer, et al.). 

However, artificially inducing plant defenses has been shown to affect the growth of plants, the reproductive process, and may negatively affect the fruit and leaves of the plant (Redman et al.; Koussevitzky et al.)Applying jasmonic acid to tomato plants can result in larger but fewer fruits, the amount of seeds produced, and the success of germination (Redman et al.). Treating plants with jasmonic acid has been shown to enhance the amount of polyphenol oxidase in the chloroplasts of the plants (Koussevitzky et al.) Excess polyphenol oxidase could cause the fruits and/or leaves to brown faster and the fruits to consist of more pigments, which is a sign of an increased rate of cell death (Araji et al.).

Equidae is a family in the order Perissodactyla in class Mammalia. It includes horses, donkeys, zebras, burros, and asses. It also included quagga but they went extinct in 1883. They are in the order Perissodactyla becuase they have an odd number of toes with the center of weight traveling through the 3rd or middle digit. In this case, those in family Equidae have a single functional toe. The single toe, or hoof, makes Equidae the most cursorial, or most adapted for running, Perissodactyla in the modern age. Equidae are grazers meaning their diet consists of grass and they are hindgut fermentors in order to digest grass. They are also polygnous. A single male stallion controls the access to multiple females. The stallions can get agressive and if another approaches, they can bite and kick with their powerful legs to ward them off. 

Evolutionaryly, horses developed in present day North America, Europe, and Asia. They were small, dog sized animals that lived in forests and had more toes. Over time, as the global climate was changing and North America became more grassland, the horses grew in size and reduced the number of digits to adapt. Eventually, modern horses became extinct in the Americas and were not reintroduced until the Europeans travelled there. 

In classifying birds, Thomas Huxley had the idea of arranging the bones of the avian bony plate, a skeletal partition between the nasal cavities and the mouth to assemble a grouping. Since Huxley set a foundation, scientists started adding more detailed characteristics such as muscles, vocalization, and toes to the group of birds but in more specific details. After the characteristics are grouped properly, birds can be present in different orders. Orders can be branch out from common ancestors with unique characters that are easy to distinguish from the rest. Songbirds, member of Passeriformes have unique morphological traits. The more complex traits are, there is a better chance that the species won’t be related. As years go by, technology makes it clearer and easier to find similarities and differences among species because not only the physical anatomy and morphologies but also DNA sequencing plays a big role in birds classification.

The last time I took a Statistics course in college was back in freshman year during my second semester of college. I vaguely remember many different concepts that were discussed in class but I would not be able to solve a bunch of different statistics problems. However there have been concepts that have come up again and again in classes that I have taken since my freshman year. An example of this would be chi square problems which seem to be very popular in biology. Chi square problems are done in order to be able to reject or not reject a hypothesis. Observed values are give and expected values are found. The way the problems work is that observed is minus expected and the value that is found is then squared and divided by the expected value. This is done for every single observed value and all of these are added together. The number at the end is then compared to the number found under the degrees of freedom and comparing the two numbers tells you whether or not we accept or reject the hypothesis. Another common thing in physics is standard deviation which is also common in biology. This just tells you the amount of variation that there is in a group as a whole. A low standard deviation tells you that the numbers are pretty close to the average while a high standard deviation tells you that the numbers are spread apart. I also remember doing something involving p values as well as doing combinations. These combinations could be solved by nCr. These are just some of the things I remember from statistics.

After performing agarose gel electrophoresis on DNA samples, the samples treated with RNase were easily distinguishable. Samples treated with RNase displayed a single band of DNA, while untreated samples displayed the same band along with a smear where the much smaller RNA strands were deposited. From this I concluded that the RNase successfully eliminated the RNA contained within the extraction samples.

For the sample treated with RNase, the ratio of the absorbance at 260 nm to the absorbance at 280 nm was 1.26, which is significantly lower than the 1.8 ratio that indicates pure DNA.  From this I concluded that the DNA extraction product was contaminated. The untreated sample had a higher ratio of 2.08, indicating that the DNA was contaminated with RNA, which has a larger ratio than pure DNA.

Additionally, the concentration of the RNase treated DNA was 0.2590 µg/µL. Because the final volume of the extraction was 50 µL, I calculated that 12.95 µg of DNA extracted. The concentration of the untreated DNA was 200.7 ng/µL, which was unexpectedly low since we would expect the nucleic acid concentration to be higher before RNA is eliminated.

The omentum is a sheet of adipose tissue that surrounds the digestive organs.  It is a common site of ovarian cancer metastasis. There are two ways in which ovarian cancer is known to metastasize.  The first is passive dissemination.  In this model, cancer cells detach from the tumor and are transported by the peritoneal fluid and ascites to their metastatic site.  Ascite formation occurs due to VEGF signaling and blocking of lymphatic vessels.  Cancer cells adhere to their metastatic site using matrix metalloproteinase (MMP), which is upregulated in cancer cells.  MMP, along with other proteins, is also responsible for enhanced cell motility.  The tumor cells then release cytokines such as interleukins to cause angiogenesis and a preferential microenvironment.  The second model is hematogenous metastasis.  Cancer cells undergo intravasation at the primary tumor site and extravasation at a distance metastatic site.  The cancer cells target their metastatic site using cancer associated fibroblasts (CAFs).  CAFs at the primary tumor site secrete proteins that upregulate pathways that promote cell motility in ovarian cancer cells.  At the metastatic site, adipocytes and macrophages form a favorable tumor microenvironment.

Yeung TL, Leung CS, Yip KP, Au Yeung CL, Wong ST, Mok SC. Cellular and molecular processes in ovarian cancer metastasis. A Review in the Theme: Cell and Molecular Processes in Cancer Metastasis. Am J Physiol Cell Physiol. 2015;309(7):C444-56.

Fractional distillation is a more viable technique than straightforward distillation because fewer material is lost throughout the procedure. Therefore, the distilled compounds are more purified in the results. The copper wire in the fractionating column acts to copy multiple distillations in one round of fractional distillation.

During fractional distillation of unknown 20, I observed a higher boiling compound at about 79 degrees celsius and a lower boiling compound at about 56 degrees celsius. There was a 1:1 ratio of higher and lower boiling points from the product collected in the vials. It can be determined that the lower boiling point compound is acetone because acetone boiling point is 56 degrees celsius. Moreover, the identification of the higher boiling point compound is 2-methyl-2-propanol. The theoretical boiling point for 2-methyl-2-propanol is 82 degrees celsius, which is about 3 degrees different from the experimental boiling point. The difference could be due to human error by heating the compound too quickly. The experimental results for this procedure are accurate because fractional distillation provide pure compounds that are less likely to be lost during the process.

Organisms in extreme temperature environments have different physiological and anatomical features that allow them to maintain a desired body temperature. In cold environments, many marine mammals have a thick layer of blubber to help insulate their bodies to stay warm. Not only does the blubber act as a thick insulator, but they also have a very integrative blood system which flows through the blubber to help maintain temperature and offer a high degree of control. Marine mammal’s flippers however are not layered with blubber. In order to keep their extremities warm in cold waters they have a counter-current heat exchange blood system. In the flippers each artery is surrounded by a system of veins. As cool blood flows from the extremities back to the heart it is warmed by the counter flowing warm blood from the heart to the extremities. Other ways for organisms to stay warm in cool environments includes: muscular activity, non-shivering thermogenesis, and an increased metabolic rate without muscular contractions.