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Animal Hormone Lab Abstract

Submitted by benjaminburk on Mon, 04/23/2018 - 10:27

Fruit flies (Drosophila melanogaster) go through a 4-stage life cycle. A life cycle that is 11-14 days long providing an efficient option for observations in a laboratory setting (Potter 2000-2016).  This cycle can be altered simply by exposing the larvae to different hormones. We were eager to see the effect varying concentrations of Juvenile Hormone, a hormone essential to fruit fly development, inhibitor had on the life cycle of a fruit fly in a lab setting (Yamamoto R1, Bai H, Dolezal AG, Amdam G, Tatar M. 2013). Because of the fact that the juvenile hormone is essential to fruit fly development we hypothesize that the overall development will be stunted and predict to see a larger percentage of larvae in trials that contain a higher concentration of inhibitor and a lower percentage of pupae in trials that contain a higher concentration of inhibitor. We mixed 10ml of water (Control) or various concentrations (0.01, 0.1, and 1) Juvenile hormone (JH) Inhibitor with 2 grams of dehydrated fly media. We then added 2 male and 2 female flies to each tube. For a week we let the flies mate in the media. In the second week we removed all the adults from each trial and placed the tubes back into the incubator. After the third week we scored the vials for: number of larva, number of pupa, number of males and female adults, average length of adults. As you can see in Figure 1 there is an upwards trend seen in the percentage of larvae as the concentrations increase, as supported by the fact that 14% of flies in the 0.01 concentration were larvae and in the vial a concentration of 1 approximately 38.4% of the full population is larvae. Also in Figure 2 a downward trend is seen in the percentages of pupae, as supported by the fact that 63.4% of the population in 0.01 concentration were in the pupae stage, while the population with a concentration of 1 only had 35.1% of the population in the pupae stage.

Volume and Osmolarity of Blood PP

Submitted by benjaminburk on Sun, 04/22/2018 - 22:06

Both factors, osmolarity and volume, of blood have lasting effects on the body and the functions that occur throughout. Both factors change independent from each other, but work together to maintain an overall homeostasis within the body. For example if an individual were to work out and drank only water then the overall osmolarity of the blood would decrease due to the increase of water. However the volume will not change because the water lost in sweat would be replaced by the water consumed. The change in the osmolarity would lead to a reduction of vasopressin release and an increase in renin production. The renin production increase would promote the reabsorption of sodium, bringing the osmolarity back to an equilibrium state. This is a prime example of independent pathways that work together within the body in order to maintain homeostasis. 

Darwin Snails Intro

Submitted by benjaminburk on Sun, 04/22/2018 - 21:53

Throughout the process of this lab many mechanisms of evolution were observable, most prominently the mechanism of natural selection. In order for evolution by natural selection to occur three requirements must be met. The first is that individuals in the population must vary in trait that is being considered. Also the trait be considered must also be heritable, meaning it must be able to be passed down from generation to generation through germline cells. Lastly there must a selection differential, which simply means that the trait being considered must either increase or decrease the likelihood of the organism to survive and reproduce. This idea of evolution through natural selection was discussed throughout the SimUText Lab and was displayed during the Flat Periwinkle snail activity. In the activity the trait of Periwinkle shell thickness was shown to be variable, heritable and provided a selection differential, in the case of this trait a thicker shell resulted in a greater likelihood to survive and reproduce in an environment that contained predation by crabs. This trend of thicker shells leading to a higher likelihood of survival and reproduction in Flat Periwinkle populations was the driving force behind the constructed hypothesis for the effects of crab predation on the Dogwinkle snail population. The Dogwinkle snail species is the species under observation in the experiment, the Dogwinkle species exists in two distinct factions, an Eastern and a Western. In the Eastern population there is a predation pressure due to the presence of Rock Crabs and the average shell thickness of the Eastern population is thicker than the Western population in which there is no Rock Crabs present. With all of this information under consideration the hypothesis reads as follows, if there is predation by crabs present and the trait of shell thickness is being observed, then evolution by natural selection will occur and a shift to a larger average shell thickness in the experimental tanks containing the Dogwinkle snails can be expected.

Darwin Snails Discussion

Submitted by benjaminburk on Fri, 04/20/2018 - 10:59

As previously stated the original hypothesis constructed before the experiment was, if there is predation by crabs present and the trait of shell thickness is being observed, then evolution by natural selection will occur and a shift to a larger average shell thickness in the experimental tanks containing the Dogwinkle snails can be expected. Based on the results it is fair to conclude that this hypothesis is supported and that when predation by crabs is present evolution by natural selection occurs. This can be concluded because in all trials the average shell thickness of the tanks with crabs, the experimental population, increased significantly from day zero to day 160. For example in Figure 1 the average shell thickness of tanks with crabs increased from 7.175mm on day 0 to 8.875mm on day 160, a total increase of 1.7mm. Meanwhile there was no trend within the tank without crabs, the control population, and the change of average shell thickness within the population was either random or insignificant. For example in Figure 1 the average shell thickness of the tanks without crabs in them change from 7.175mm to 7.4mm, a total increase of .225mm, a much less significant change than the 1.7mm observed in the tanks with crabs. This change in the experimental population proves that evolution by natural selection occurred when predation by crabs was present because the fact that the trait of shell thickness was heritable and variable was already known, but the significant change from thinner to thicker shells in populations where predation was present proves that there is a selection differential when discussing shell thickness, more specifically it can be concluded that thicker shells provide the organism a higher probability to survive and reproduce. This conclusion reiterates the three requirements needed for evolution by natural selection to occur being, heritability, variability and selection differential. Also the interval and duration of the experiment being only 160 days shows exactly how quickly and effectively natural selection can occur in and change a population.

Hill Reaction Lab Introduction

Submitted by benjaminburk on Thu, 04/19/2018 - 13:13

In this experiment the goal was to see the effect of certain factors, in this case acids and bases, of the light absorbance of spinach chloroplasts. Chloroplasts are essential to life for both plants and animals alike, they are crucial in the photosynthetic reaction that produces oxygen and glucose from carbon dioxide, light and water. In the spinach chloroplasts there are two separate photosystems that convert light energy and water to oxygen and glucose. In this experiment the chloroplasts were extracted from approximately six spinach leaves and suspended in grinding buffer. 50 microliters of the chloroplast were then placed into four differently treated test tubes (dark, light, light and vinegar and light with bleach), leaving one test tube without chloroplast as the control group. The light absorbance of each test tube was tested every 10 minutes for 30 minutes. If bleach and vinegar are added to the chloroplast then we can expect the function of chloroplasts to be hindered because the acid and base produce an environment that is outside the optimal ph for functioning chloroplasts. More specifically we can expect the bleach to completely neutralize the chloroplast and for the vinegar to almost completely neutralize the chloroplast, but we can expect limited function. For these predictions to supported we should expect to see the tube with bleach to have 0 light absorbance and for the vinegar treated tube to have a very low light absorbance.

Tetrahymena Lab Discussion

Submitted by benjaminburk on Wed, 04/18/2018 - 22:26

Tetrahymena cells are unicellular predatory ciliates that produce both sexually and asexually. To begin the experiment we made a master tube of 5ml of Tetrahymena and 5ml of India ink. Immediately after and then every ten minutes for forty minutes a random sample of 100ul of Tetrahymena cells were taken and added to 50ul of glutaraldehyde, killing the cells without damaging the tissues. Once mixed, 35ul of the dead Tetrahymena were put under a microscope and then ten randomly chosen cells were observed at 10X and had their black food vacuoles counted. The counts were averaged and the standard deviation calculated. Tetrahymena not randomly chosen were excluded from the experiment. This experiment showed a tendency of the Tetrahymena cells to increase their consumption rate over time, as seen by the upward slope of the graph.

Paternalism discussion

Submitted by benjaminburk on Tue, 04/17/2018 - 16:14

Paternalism is a very controversial topic that has such persuasive pros and cons that most arguments about the topic tend to end without a definitive winner. Paternalism by definition is the overriding of ones autonomy for their own good. For a person to be completely autonomous they must be able to make decisions on their own without pressure from others and without any violation of their free will. This idea of paternalism comes up very often in the medical field, which has led to many controversial cases where doctors exercised or did not exercise medical paternalism. In my opinion I side with Goldman who believes that medical paternalism is more often than not unjustified, unless faced with an exceptional situation. One of Goldman’s strongest arguments in my opinion is that most people tend to not value mere existence in this world, many people on earth cherish purpose and a quality life over simple existence. In plainest terms this simply means many people if put in a position to live on life support in a coma or to die, would choose to die because a life on life support in a coma is not one filled with purpose or enjoyment. With this in mind I do not believe it is within a doctors rights to override a patients decisions because the doctor believes it is what is best because the doctor is most likely unaware of what the patient values most in their life and it very well may not be their existence, it may be their religion or their enjoyment of their life. Also I believe that as humans one of our greatest privileges is free will and the ability to make conscious decisions for ourselves, and medical paternalism in many cases violates that ability and in my opinion that is wrong, even if it is for the patient’s own good. I believe that as long as a patient is fully aware of the consequences and they are of sound and independent mind, they should have full control over their life. All in all I believe that medical paternalism as a whole is morally impermissible, I do believe there are exceptions but those rare circumstances are few and far between and as a whole the idea of medical paternalism is morally impermissible because it violates the basic human right of autonomy.

Volume and Osmolarity of Blood

Submitted by benjaminburk on Tue, 04/17/2018 - 11:51

Both factors, osmolarity and volume, of blood have lasting effects on the body and the functions that occur throughout. Both factors change independent from each other, but work together to maintain an overall homeostasis within the body. For example if an individual were to work out and drank only water then the overall osmolarity of the blood would decrease due to the increase of water. However the volume will not change because the water lost in sweat would be replaced by the water consumed. The change in the osmolarity would lead to a reduction of vasopressin release and an increase in renin production. The renin production increase would promote the reabsorption of sodium, bringing the osmolarity back to an equilibrium state. This is a prime example of independent pathways that work together within the body in order to maintain homeostasis. 

Cyclohexane PP

Submitted by benjaminburk on Sun, 04/15/2018 - 20:09

Cyclohexanol was dehydrated in an effort to synthesize cyclohexene, in this experiment cyclohexene was obtained with a 23.1 % yield. The distillation process and washing procedures as described in the procedure were followed successfully. The gas chromatography and IR results suggest that the product was cyclohexene and extremely pure. This is supported by the fact that the gas chromatography result has only one peak that takes up the entire area on the graph, this means that the substance that the test was performed on was homogenous and pure. The IR graph also proves that the substance is cyclohexene because it contains the respective peaks for the substances that make up cyclohexene and in the correct ratio as well. The potassium permanganate and bromine dichloromethane tests also produced the expected results for both cyclohexane and cyclohexene further supporting the conclusion that the end product was pure cyclohexene.

Off switch of capases

Submitted by benjaminburk on Sun, 04/15/2018 - 20:01

Caspase-3 is a protein invloved in apotosis or programmed cell death. The protein also has a key role in overall cell development when expressed in low levels. A new research study has helped show the balance of the two pathways through biophysical, structural and computational approaches in order to demonstrate the phosphorylation of conserved sites. These results helped provide new insights into allosteric regulaton mechanisms and new opportunities for modulator developement. These new developements will help give more precise information on the cells developement and death cycle. 

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