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Discussion

Submitted by dalon on Wed, 11/22/2017 - 08:51

N-propyl propionate was synthesized via Fischer esterification using sulfuric acid as a catalyst with a 32.9% yield. The product was identified using an IR test. The IR test was used to measure bond vibrations and the absorption of IR radiation in order to determine which bonds were present in the compound via wavelength, thus indicating if the ester bond was present. The accepted IR reading for the C=O bonds present in an ester is 1740 1/cm. As demonstrated by the IR graph attached, there was one sharp peak observed at 1741 1/cm, indicating the presence of the C=O ester bond; however, there were also two peaks observed at 2,972 and 2,883 1/cm. These fit in the range of carboxylic acid –OH presence, which has a range of 3,400-2,400 1/cm, indicating that some of the alcohol was left behind and therefore the mixture was not a pure ester. In addition, when the odor was observed the smell of alcohol was still present in addition to the sweetness of the ester, indicating that the ester was not pure. To improve the experiment, in the future there should be more steps separating the aqueous and organic layers through mixing and drying, yielding more of a purer product. The purity of the product was assessed and was deemed to be impure due to the IR spectroscopy reading and odor observation results.

procedure

Submitted by dalon on Mon, 11/20/2017 - 08:56

To a 5 mL RB flask, 0.95 mL of propionic acid and 0.824 mL of n-propanol was added via pipet. To the RB flask, 4 drops of sulfuric acid were added and the mixture was thoroughly mixed by drawing the contents into a pipet and then releasing. After mixing, boiling chips were added to the RB flask. The RB flask was then connected to an air condenser and a side arm with the side arm pointing 45°downwards towards the sand-bath. The flask was lowered into the sand-bath and gently boiled for 15 minutes after the first water droplets were observed in the side arm. After 15 minutes, ½ of the contents in the sidearm were dropped back into the RB flask and the apparatus was lowered again and heated another 15 minutes. The sidearm was then again tipped until the upper phase of the side arm was in the flask, and the mixture was heated for another 15 minutes. At the end of the last 15 minute window, the apparatus was removed from the sand-bath and allowed to cool to room temperature for 12 minutes. After cooling, the mixture was removed from the flask into a centrifuge tube containing 1 mL of water via pipet and the two layers were mixed in the tube. The aqueous layer was then removed to liquid waste. To the centrifuge tube, 1 mL of saturated aqueous sodium bicarbonate was added and the layers were mixed again and the lower layer was removed. To the remaining mixture in the tube, 1 mL of saturated aqueous sodium chloride was added and mixed, and the lower layer was removed. The organic layer was then pipetted into a new vial and 4 spheres of anhydrous CaCl2 were added and swirled in the mixture. The vial was then left to sit for 5 minutes and after 5 minutes the remaining liquid was moved to a new vial. The odor of the product was then noted and an IR spectrum test was performed.

 

edit

Submitted by dalon on Sun, 11/19/2017 - 08:01

The reason the brain is so sensitive to changes in blood flow is because of the tight regulation of what goes in and out of the brain, which is maintained via the blood brain barrier. In order for molecules to move into the brain, they must pass via the endothelial cells. Gases and hydrophobic substances can cross via diffusion; however, substances such as carbohydrates and amino acids are dependent on mediated transport, and are selective for very specific molecules; therefore, any changes to which molecules are present in the blood at the time could impact the flow of molecules into the brain via the tightly regulated blood brain barrier; however, because the brain relies on glucose to function, there is a specific mechanism for glucose to cross the blood brain barrier. Glucose can readily cross the blood brain barrier by facilitated diffusion because transport proteins that carry the glucose are found in the cell membranes. Thus, glucose is carried over by GLUT-1 carriers, independent from the GLUT-4 carriers that rely on insulin. 

co2

Submitted by dalon on Fri, 11/17/2017 - 10:59

Low levels of CO2 result in constricted arteries are caused by constriction by the smooth muscles in order for the oxygen concentrations to decrease and the carbon dioxide concentrations to increase. Thus, the transportation of oxygen rich blood is restricted because the main transportation of the oxygenated blood from the heart to the rest of the body, the arteries, is restricted via vasoconstriction. If not enough blood reaches the brain, a common symptom is often dizziness, which would be explained by the restricted arteries.

vitamin C edit

Submitted by dalon on Fri, 11/17/2017 - 10:58

This is due to the fact that in order for the vitamin C to be reabsorbed into the plasma, it must be actively transported out of the tubule. These carrier proteins or pumps can become saturated, at which point they are carrying the maximum amount of vitamin C the transporters can, and the rest will be excreted because it has surpassed the renal threshold, which is the concentration of solute that appears in the plasma when the transport maximum is reached. Thus, if a person takes 1000-mg of vitamin C once, it is much likely to oversaturate the transporters and thus be urinated out; however, with 2 500-mg doses, it is more likely to be reabsorbed.

cloning

Submitted by dalon on Thu, 11/16/2017 - 17:11

In addition, due to potential imprinting errors and the mature age of the somatic cell, the clone could be born with serious health complications, assuming it can even be created. Humans receive a copy of a gene from their mother and father; however, in certain cases only one of the genes is turned on and the genetic information coming from the appropriate source, either from the mother or father, is “stamped” through DNA methylation, which signals whether or not the gene should be used. In cloning, due to rushed chemical reprogramming, this process is usually defective. Chemical reprogramming includes wiping away some, but not all, old epigenetic tags, which are required for embryo development because this allows the one starting gamete cell to eventually develop into other cell types. In a typical egg, chemical reprogramming takes years, but in cloning, the process must be done quickly after the new nucleus is inserted into the egg, which can cause genetic disorders. For example, many animal clones suffer from Large Offspring Syndrome, which results in the clone having a higher birth weight and enlarged organs, which leads to respiration and circulation problems. This disorder was linked to misplaced methylated DNA tags due to imprecise imprinting, likely attributed to rushed chemical reprogramming. In addition, due to the fact the somatic cell comes from an aged source, even if the age is only two years old, the telomere length is of concern. At the end of each chromosome there are compound structures called telomeres. When the cell divides, the telomere shortens somewhat each time until it becomes too short and the cell undergoes programmed death. Due to the fact the somatic cell coming from Jason has already divided previously, and therefore has shorter telomeres, the cells in the clone could die prematurely.

    

procedure edit (#2)

Submitted by dalon on Wed, 11/15/2017 - 15:11

Boiling stones, 0.064 grams of sodium hydroxide, and 0.200 grams of 2-napththol were added to a 10 mL round bottom flask. 3 mL was added to the RB flask and an air condenser was attached to the flask. The sand bath was turned on upon arrival to 30% and the flask was lowered so it was hovering above the sand. The mixture was refluxed until all the solids were dissolved and then for another 25 minutes. Through the top of the air condenser, 0.200 mL of n-butyl iodide was added and the flask was lowered into a position just above the sand bath to reflux for another hour. 50 minutes into the reflux time, 25 mL of water was cooled in an ice bath until the completion of the reflux. The reaction mixture was poured over 10 grams of ice in a beaker and any mixture that remained in the RB flask was rinsed using the cooled water. The contents of the beaker were mixed until 95% of the ice melted. The product was then collected using suction filtration for 25 minutes. After 25 minutes, a small amount of the product and the starting material were analyzed via a 3 lane TLC analysis in a 95% hexane 5% EtOAc mixture, a 5% hexane and 95% EtOAc mixture, and a 20% hexane and 80% EtOAc mixture. The percent yield was then also calculated.

 

lab

Submitted by dalon on Tue, 11/14/2017 - 16:24

The lab that most interested me was Mariana Pereira’s lab regarding mother/child interactions. There were three main facets to Professor Pereira’s lab. The first facet was just in general what the different brain structures were that are involved within mom/child interaction. Professor Pereira found that there were limbic-cortical-striatal interactions and also that the mesocorticolimbic dopamine system was involved. Another facet of Professor Pereira’s research was how postpartum depression in mice affected mouse interaction with the pup. Some observations made were that the mouse licked her pup less often and generally interacted with the pup less. In addition, the third and most interesting facet to me, was the impact drugs have on the mother/pup interactions. Although Professor Pereira briefly discussed this, through my own meeting with her she summarized it well. The mice that are addicted to cocaine are more likely to choose to use the cocaine rather than take care of the pups. This is especially interesting because of the VTA system and the dopamine release due to the fact cocaine is known to release dopamine into the VTA system and is the cause for the addictive effect. Therefore, this could potentially demonstrate that the cocaine use overrides the mother’s instinct to take care of her pup.

post lab answers

Submitted by dalon on Mon, 11/13/2017 - 21:55

A saturated fat has no carbon-carbon double bond. A monosaturated fat has a single carbon-carbon double bond in one or more of the carboxylic acids and a polysaturated fat has 2 or more carbon-carbon double bonds in the carboxylic acid moieties. Trimyristin does not possess any carbon-carbon double bonds and can therefore be classified as a saturated fat. Using the older procedure of sudden cooling, as in cooling directly in the ice bath, the crystals observed would be smaller and temporary. This is because if you cool it too quickly, there is a chance that more precipitate would form in place of crystals and the precipitate would not catch in the filter paper. Thus, the yield would be very small. 

Discussion

Submitted by dalon on Sun, 11/12/2017 - 21:01

Trimyristin and myristic acid were obtained through an extraction reaction using recrystallization and hydrolysis techniques with tert-butyl methyl ether and acetone. The products were primarily identified using melting points and their identity and purity was assessed. The observed melting point of once recrystallized trimyristin indicated an impure substance due to a wide 5 degree range of melting and a lowered melting point in comparison to the accepted melting point of trimyristin of 56–57 °C. In recrystallization, in order to obtain a pure compound, insoluble impurities are removed by dissolving the compound in a solute that has similar structural features then filtering out any insoluble impurities; thus, to further purify the impure trimyrisitin, as determined by the melting point, we had to recrystallize again to remove the impurities remaining in the compound. The twice recrystallized trimyrisitin resulted in a purer product as indicated by the small melting point range, 54-56°C; however, it should be noted that the observed melting point is still slightly lowered than the accepted melting point and could potentially indicate a still impure product. Myristic Acid was obtained from the once recrystallized trimyristin with a melting point of 49-52°C, with the accepted melting point of 54.4°C. The wide range and lowered melting point again indicate an impure compound. In order to improve the purity and yields, as indicated in the results section, of the products, we should allow the crystallized solution to cool completely to room temperature before submerging in the ice water bath. Not only will this result in larger crystal formation, but it would ensure that all the ether soluble components would dissolve before being put into the ice bath and thus the purity of the crystals would improve because the soluble dissolved impurities would be fully filtered out upon filtration. The purity and identity of the products were tested and the twice recrystallized trimyristin was determined to be pure; however, the once recrystallized trimyristin and myristic acid were determined to be impure.

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