Titration of Amino Acids and Peptides

Titration of Amino Acids and Peptides Titration is the process used to analyze the acid-base behaviour of amino acids and peptides. A 0.25 g sample of unknown amino acid and aspartame were transferred quantitatively to separate 250-ml Erlenmeyer flask. 20.0 ml of distilled water was added to each flask using a volumetric pipette then the flask was swirled to dissolve the samples. Small increments of 0.200 M HCl were added to both samples to produce an acidic solution and then each sample was titrated by adding 0.200 ml of 0.200 M NaOH. The pH of the acidic solutions was measured from 1.5 until it reaches pH 11 and it was recorded in every addition of the base. On the Aspartame, the total volume of the base added was 8.0 ml and 29.6 ml on the unknown amino acid. Titration curves were constructed based on the pH values and volume added. The identity of the unknown amino acid was revealed to be Aspartic acid. A titrimetric profile of the amino acid and aspartame were drawn. INTRODUCTION Proteins are the most important class of biochemical molecules, next are carbohydrates and lipids. Proteins are the basis for the major structural components of animal and human tissue. Proteins are also the indispensable agents of biological function and amino acids are the building block of proteins. Amino acid is an organic compound containing an amino group (-NH2) and a carboxyl group (-COOH). Since amino acids contain both an acidic and a basic group, they undergo an intra molecular acid-base reaction and exist primarily in the form of a dipolar ion, or zwitterions. Amino acids are also amphoteric, meaning, they can react either as acid or base depending on the circumstances. There are basically 20 primary amino acids that serve as the backbone of most proteins. Peptide is a molecule that consists of two or more amino acid linked together by bonds between the amino group and the carboxyl group. Although their structures are less complex than the larger protein molecules, peptides have significant biological activities. Titration is a useful tool in determining the reactivity of amino acid side chains. Since amino acids contain an ionisable group, the predominant ionic form of these molecules in solution depends on pH. Titration of amino acid shows the effect of pH on amino acid structure. Titration is also useful in determining the isoelectric pH of the sample. MATERIAL AND METHODS A 0.250 g sample of unknown amino acid powder was placed on a 250 ml beaker using an analytical balance. 20.0 ml of distilled water was added to each flask using volumetric pipette and then the flask was swirled to dissolve the sample. Small increments of 0.200 M HCl were added to the dissolved sample using a syringe until the pH value is 1.50. Both acidified solutions were titrated by adding 0.20 ml of 0.200 M NaOH. The pH was measured and recorded at each amount of base that was added. The procedure was repeated until the pH of the solution reached 11.0. Same process was done using commercial aspartame. Titration curves of the unknown sample and that of aspartame were constructed using MS Excel. The unknown sample of amino acid was identified based on the pKa values and pI that were seen in the constructed titration curves. Titrimetric profiles of aspartame and the identified amino acid were drawn. Then the total percentage errors of the pKa and pI were calculated. RESULTS AND DISCUSSION The unknown amino acid was recognized by comparing its experimental value to 20 amino acids. In able to do that, a titration curve must be drawn. The unknown amino acid was recognized as glutamic acid and it was determined based on its pKa and pI value from the graph. In the titration curve of the unknown amino acid, it can be observed that at the pH reading of 2.16, 10.3 and 4.4 the graph shows an inflection curve making it the pKa values of the unknown sample. These reading were compared with the pKa values the 20 amino acids and it was observed that the experimental pKa values were close to the pKa values of glutamic acid. Identity of Unknown Amino Acid: Glutamic Acid Percentage errors between the experimental and theoretical pKa values of the Unknown amino acid were computed and the results were 4.11 %, 6.51 % and 3.53 % and the percentage error between the pI values of experimental and theoretical is 6.32%. The possible sources of errors were probably the inaccurate weighing of the sample and the measurement in adding HCl/NaOH. During titration, the prototrophic groups lose H+ successively as the pH reach their respective pKa values. The net charge of glutamic acid at the start of the titration is +1 and as each group loses H+ the net charge will decrease by one unit. The acidified Aspartame solution was titrated using 0.200 M of NaOH. The titration curve above shows the inflection points. These points are 2.5, 10.5 and 3.4. The possible sources of errors were the inaccurate weighing of the sample and the measurement in adding HCl/NaOH is not precise. During titration, the prototrophic groups lose H+ successively as the pH reach their respective pKa values. The net charge of aspartame at the start of the titration is +1 and as each group loses H+ the net charge will decrease by one unit. Other possible source of errors on the experiment was the inaccurate plotting of pKa values on the titration curve. Wrong pKa will cause the identity of the unknown sample to be incorrect. The buffering zones of glutamic acid are at 2.16 and at 10.3. In aspartame, the buffering zones are at 10.5 and at 3.4. Both are suitable as buffers on acidic pH. Aspartame has a taste that is close to sugar. It enhances the flavour and does not cause the teeth to decay. There is a scientific study that shows that aspartame is beneficial in weight control and it is helpful for individuals with diabetes because it allows them to please their taste for sweets without affecting their blood sugar level. Aspartame can also result in fewer calories, which helps people with diabetes, manage their weight. Aspartame hydrolyzes into its respective amino acid when heated. There are also unpleasant side effects of aspartame utilization which includes loss of memory, seizures, headache, blindness, protruding eyes, palpitation, depression, insomnia, diarrhea and skin rashes. Aspartame blocks and lowers the levels of serotonin, tyrosine, dopamine, nor epinephrine and adrenaline. As a result, it is typical that aspartame symptoms cannot be detected in laboratory tests and on x-rays.

the bell jar :: essays research papers

The book â€Å"The Bell Jar† by Silvia Plath was different from other books assigned through-out my time at high school. Most of the other books, including for example â€Å"Of Mice and Men†, Lord of the Flies†, and â€Å"The Heart of darkness† were stories about mostly men and how they all turned against each other in some way and acted like animals instead of humans, and in the end of all of them someone dies. The book â€Å"The Bell Jar† though is without a doubt my favorite so far because it is about a female and about all the pressures of everyday life that run through her head. This is something that I can relate to because I too think about some of these same worries such a as virginity, looks, and morals to name a few. I am claiming that the theme or the meaning of this book is that in order to stay sane in this world, you can’t let the pressures and worries run your actions and decisions and your life or else you will not be able to function. I feel that this is what happened to Esther. I think that these pressures to Esther are what set her over the edge and made her think the way that she did and made her think that something was wrong with her.   Ã‚  Ã‚  Ã‚  Ã‚  Sylvia Plath portrayed a lot of meaning in this book. The main idea and meaning that she, as a writer, was trying to portray to the reader, is to understand how the worries, burdens, and pressures of being a young, mature adult are enough to put someone, like Esther in a depression so deep that it gives the illusion to the reader that she is insane and not in touch with reality. I believe that it is a matter of her being depressed and not of her being insane because of all that is on her mind she cant think clearly which makes her seem insane because if the strange things that she talks of such as not being able to sleep or eat, or even write. I think that the author did a very good job of making her seem depressed to the point of â€Å"insanity† because of how she Esther feel like she wasn’t sleeping when really she was sleeping for hours upon hours when she was put into the institutions. At an earlier

Historical inaccuracies in Ridley Scott’s film `Gladiator Essay

In recent years the emergence of filmmakers who expressed interest in adapting historical events as wide-screen presentations has revitalized public interest on historical events. But the usual problem is that the general public’s view usually gets distorted due to contemporary filmmakers’ nasty habit of utilizing their artistic license to its full extent More often than not, adaptations of historical events like Ridley Scott’s Gladiator offers a glimpse of early civilizations but neglects the aspect of historical accuracy which in turn cannibalizes scholarly efforts to reconcile public interest in the actual historical events. The glitz and glamour of commercial cinema is in large part responsible for the historical inaccuracies of Ridley Scott’s Gladiator. Martin Winkler (17) suggests that the reason behind a historical film’s departure from its origins is that the fiction which causes the inaccuracy is what sparks viewer interest in the first place. In accordance to Winkler’s theory, the elements incorporated in Gladiator contributes to the film’s historical infidelity; its principal characters, chronology, production design, and supposed intent of exhibiting the authentic life and culture of Imperial Rome, has been diluted by the filmmakers’ aesthetics. As per what the film entails, the structure of the Gladiator’s narrative appears to be drastically shortened. Commodus’ reign was marked by numerous assassination plots, including a scheme that involved her own sister Lucilla, all accounts of murdering the treacherous emperor have neither been established nor even mentioned in the film. Historical accounts further suggest that Commodus’ reign ended 13 years later upon his assassination (Boatwright, Gargola, & Talbert 405-406), the film, on the other hand, although the time frame of events were never actually mentioned or given much attention, it illustrated that Commodus reigned no more than two years (Ward 33). The film also depicts that Emperor Commodus died in a gladiatorial duel with Maximus, obviously in a coliseum, with the intent of bringing back democracy to Rome and re-establishing the country as a republic. While the 73rd book of Cassius Dio’s eye-witness account of Roman History imparts that a wrestler who popularly went by the name Narcissus choked the life out of Commodus, and the incident happened in the emperor’s bath. The film’s characters also share an extent of inaccuracy with the actual historical personalities from which they are derived from. Evidently, from appearance to characteristics, the film’s Commodus did not reflect the Roman Emperor whom history recognized. Primarily, Commodus’, in the film, is bequeathed as a dark hared man in his mid 20s who fights with his right hand and has an underdeveloped physique (Ward 33). While the historical Emperor Commodus was and 18-year old blonde with a well developed physique and fought with his left hand (Kyle 224-227). Likewise, the actual description of Commodus’ personal traits was inconsistent with the film as the historical Commodus was notorious for his corruption, violence, and lust for blood. The film shows the aforementioned characteristics through Commodus’ fixations on sports such as beast-hunting, chariot-racing, and gladiator combat as well as his claims to have won over 1,000 battles (Ward 32). However, Scott’s incarnation contradicts the true nature of the roman emperor as he is characterized by his guiltless lack of emotion and compassion, ruthlessness, cowardice, and mental instability (Hekster 53-56). Contrary to the film’s illustration that Lucilla had an 8-year old son named Lucius Verus, Allan M. Ward’s Gladiator in Historical Perspective entails that, historically, the son who went by the name Lucius Verus died during infancy. Also, Lucilla gave birth to three children during her marriage with Lucius Verus Marcus and only one of the three children survived and grew up, an unidentified daughter who became part of the assassination scheme against Commodus. Lucilla, however, bore a son but she did so in her marriage, with Tiberius Claudius Pompeianus, and the boy’s name was Aurelius Commodus Pompeianus who was 6-years old during the time of the film’s events. Similarly, the reason behind the strained father-daughter relationship between Lucilla and Marcus was the latter’s arrangements of a second marriage for his widowed daughter. Apart from the disrespecting reality that the second marriage occurred only 9 or ten moths after Verus’ demisae as well as the tremendous gap between the couple’s ages (Lucilla was 19 while Claudius Pompeianus was approximately in his 50s), Lucilla also felt undignified by the fact that her new spouse came from a family of provincial equestrians in Antioch, Syria (Ward 33-34). However, the film did not took such event into account leaving the reason behind the cold relationships between the former emperor and former Augusta vague (Ward 33-34). The film’s central character Maximus Decimus Meridius, is a fictional character based on the archetypes of able-bodied men from the far reaches of the empire’s jurisdiction who served as the materialization of Marcus Aurelius’ persisting idea of using men beneficial to the imperial cause (Ward 38). To a similar extent, Maximus’s character is attributed to two recognizable Roman political and military personalities, Marcus Nonius Macrinus who was one of Marcus Aurelius’ closest friends and Tiberius Claudius Pompeianus who was partly responsible for the Roman triumph over Marcomannic War in the film’s beginning (Popham). George Depue Hadzsits (70) suggests that a film such as Gladiator is more likely to revive interest in the subject of history considering that scholarly efforts simply produce fragments of history which does not fulfil the human yearning for knowledge. Hadzsits furthers that despite such visual spectacles’ temporal didactic value and lack of attention on the angle of accuracy, at least the interest for the subject matter is roused (Hadzsits 71). The problem with Gladiator, conversely, is that its revival of interest in Roman History, or ancient world history for that matter, seems to delineate the supposed dissemination of ancient Roman culture and alters it with norms that the filmmaker deems right. In terms of production design, the armour and weaponry worn and yielded by the gladiators appear to have a medieval design rather than Roman. Allan Ward (39) writes that gladiators had already been placed under categories like eques or horseman, provocator which is believed to be the term for challenger, murmillo or what is considered as water combatants, hoplomachus or gladiators who wield heavy weaponry, retiarius the net fighters, and secutors or contraretriarius otherwise characterized as the light armed fighters. However, Ward (39) argues that the film does not seem to highlight the distinctions between gladiators as all of the competitors generally wore the same armour with little differences in weapons of choice. Ward furthers that each fighter category comes with a different set of weapons and armour as well as a different style in combat. The matches between two gladiators are dependent of their category and fighting abilities, a secutor, for instance was often matched with a retriarius, perhaps due to the resemblance in the nature of their weapons and battle skills. Moreover, gladiators within a similar category were not paired to pit against each other, with the exception of the horsemen and the challengers. As mentioned earlier, one of the premises tied with Gladiator is the tendency to rouse interest on the life and culture of ancient Rome, but in this context the film is also inaccurate. James R. Keller (88) implicates that Gladiator imposes the American devotion to the principles of democracy. Initially, the final confrontation between Maximus and Commodus should incite the cultural importance of gladiatorial combat in ancient Rome, however, the re-arranged plot of the film that caused the conflict between the former general and the treacherous emperor to fail in its attempt to do so. The conflict then suggests that Maximus represents every working class, freedom loving American while Commodus serves as the embodiment of the corrupt, insensitive, and inconsiderate aristocrat (Keller 88). In its inaccurate entirety, Gladiator has proven itself to be more of a costume drama adaptation rather than a re-telling of an antiquated historical tale. Despite the filmmakers’ efforts to conduct research and seek consultation for relevant information about the film’s source, the direction remained in the production people’s perspective and not with the scholarly one as the motion picture continued with the re-arranged biographical information of the characters and the reformatted events in the lives of the characters. In addition, the film simply delivered a visual spectacle rather than a knowledgeable historical fact. Martin M. Winkler (204-205) writes that film producers and other individuals concerned with marketing cultural products habitually call on scholars to guide them in marketing historical films. This is, in large part, brought about by producers’ beliefs that scholar credibility is enough to amplify the promised prestige and revenue of their product. Scholarly prestige according to Winkler is mainly vital as a marketing strategy, but a more appropriate term seems to be deceptive advertising as investing parties and supposed artists convince the public of the accuracy of their distorted historical documentation with the aid of renowned experts

morality essays

morality essays The very essence of leadership is that you have to have a vision. -Theodore Hesburgh. This necessary essence of leadership is a vision, not a mirage, but a realistic goal of gaining a successful Foreign policy. Economic sanctions are effective and necessary. They are a moral and accepted method of achieving Foreign Policy goals. Now to define some of the words of the resolution: Economic sanctions: Penalty relating to commercial prosperity for non-compliance Achieve: to get or attain by effort Foreign policy: the policy of a sovereign state in its interaction with other sovereign states Goals: result or achievement toward which effort is directed Economic sanctions have been and are accepted as a legitimate method of foreign policy. According to Jonathan Eaton, sanctions have long been important in international relations and us law prescribes the use of sanctions in circumstances related to, for example, national security, human rights, intellectual property, and international trade. Ec4enomic sanctions are currently a reality of international relations; getting rid of them would be as ineffective as outlawing war. Economic sanctions have always been an American Foreign Policy weapon. Even the American colonies imposed sanctions on Britain in response to the stamp and townsend acts. Sanctions have been vital weapons for Foreign policy for more than 200 years. I must agree with U.S. representative Ros Lehtinen when he says, sanctions made sense form a moral, ethical, political and commercial sense. Sanctions are a step taken to avoid war, and this I believe can be a given that sanctions are much less severe than war. With this in mind the price per American for U.S. sanctions is $3.77- a little more that the cost of a Big Mac and Fies. For a moral effective method of achieving Foreign Policy goals it is also very cost effective. According to the Journal ...

Comparison between the two movies of essays

Comparison between the two movies of essays Comparison between the two movies of The author of the written version of The most dangerous game was Richard Connell and that story is interested and very exacting. This story occur one of series of details which give a little of suspense but in fact that is not enough. During the story in every part present a little kind of suspense but the suspense is manipulated at the price of consistency. Actually exist many movies which are related with these story and maybe our life also will be outline as a very dangerous game. Both movies which I see, old version and other most recent movie, present some different between, but in both we can see the important action which I call, the real life-and-death struggle, thats the mean of the title, The most dangerous game. In the old version movie start when the yacht is destroy and the passenger treat to reach a desolate island but only one reach them. These man calls Rainsford see some light in looks like a castle. When he arrive to a castle the action start and also the different between both movies star here. In the castle had four addition people and one of them was dump and he was the first person which Rainsford see. The actions are increasing up to Rainsford, with the help of the women; see which he is in the wrong place. He and the women find the place which the General Zaroff commits the murder. The other movie which I see, the actions occur in the forest. In these part had more people than the other movie. During this movie Rainsford had to run to keep alive, that because General Zaroff and their group will be hunt with rifle, arc and arrow, and this group own four tracks, one of the disadvantages of Rainsford has in the second movies which not present in the first. The Rainsford run he decide to turn again to the house and break the padlock of one of the door and then he see human part in small bottle and ther ...

SPECIAL SEGREGATED SCHOOLING CONTINUES TO ISOLATE PEOPLE WITH Essay

SPECIAL SEGREGATED SCHOOLING CONTINUES TO ISOLATE PEOPLE WITH DISABILITIES FROM MAINSTREAM OF SOCIAL AND ECONOMIC LIFE. CRITICALLY DISCUSS - Essay Example With Porter (2001) appreciating the diversity in definition of children with disabilities, the definition by National Council of Education Research and Training, NCERT (2006, p.2), includes those with physical challenges in intellect, hearing, vision and locomotion together with victims of social conflicts and natural catastrophes, street children and those that would be extremely deprived socially and economically. Scholars have linked their lower participation in the national workforce largely to exclusion from educational systems which yields poverty and dependence among these persons, causing them to live in isolation, despair and neglect. This paper looks at the effect of segregated schooling in isolating people living with disabilities from the economic and social opportunities in the society. Indeed, specialised segregated schooling isolates people living with disabilities from tapping into the mainstream of economic and social life. Taking the Irish context as an example, its schooling system was segregated and separated for pupils considered as handicapped as early as in the 1950s with pupils being excluded from regular school setting to specialised schools (Winter & O’Raw 2010, p.6). But due to international influence, this system was slowly scrapped off with an inclusive education system being adopted albeit some portions of the specialised schools were maintained. The World Health Organisation, WHO (2011) notes that even in countries where enrolment to primary schools are high like in Eastern Europe, a large portion of children living with disabilities fail to attend schools. As of 2002, the rates of their enrolment stood at 59%, 58% and 81% as compared to 93%, 97% and 96% among the normal children in Romania, Moldova and Bulgaria respectively. According to the National Disability Authority (2011), in Ireland, 64% of

Cause and Effect On Honolulu Rail Transit Essay Example | Topics and Well Written Essays - 500 words

Cause and Effect On Honolulu Rail Transit - Essay Example Thus, many pros and cons have been raised about the proposed construction of the rail transit. Although, the Honolulu rail transit will ease movement of commodities and people from urban areas to outlying areas, it will lead to budget cuts on the capital projects and contribute to environmental, health as well as aesthetic issues. The Honolulu Rail Transit project is costly; thus, it will cause the budget cuts. The rail debt will rise contributing to the reduction of spending on other capital projects. The construction of the rail transit will enable the government to incur additional debt for other projects such as flood control programs, police equipment and road repairs. This is because the financial resources of the city will be directed to the rail construction, as the city will be forced to alter al the city expenses to the rail construction. For instance, the report from the financial director of Honolulu, Toy Arre, revealed that  the fiscal budget proposal of 2013 on health and safety alone is $ 17 million dollars  (Levine pr 3).  The public health and safety is on the front line, but this will be impacted by the proposed rail construction because the government will not manage to meet all other proposal fiscal budget. Hence, this will contribute to the government relying on foreign aid and borr owing money from other developed states with an aim of meeting other capital projects; thus increasing the national balance deficit. The Honolulu project may pose environmental, health and aesthetic issues. This is because the construction activities will contribute to varied consequences on the environment and the health of human being; thus, the project poses legal issues. The plaintiffs included in the environmental and legal issues indicated that the construction of the rail will lead to environmental pollution. For instance, the electric train will be powered by fossil fuel because this comes from burning of petroleum products. This