A problem solving model for Wal-Mart Essay Example | Topics and Well Written Essays - 2500 words

A problem solving model for Wal-Mart - Essay Example The largest retailing company of the world, Walmart has been facing a decline in sales in the US, continuously for â€Å"nine straight quarters†, according to The Wall Street Journal. This has been partially due to the economic recession and partially owing to the negative image that has been there for this company. In order to suggest a package of solutions to get over with this â€Å"sales slump†, this paper invisages synthesizing different organizational theories, with a focus on three- the neoclassical theory put forth by Roethlisberger and Dickson (1943), the socio-technical theory proposed by Pasmore and the contingency theory evolved by Hellriegel and Slocum (1973). This project will put forth innovative and creative solutions to rectify the sales slouch in Wal-mart, using the problem-solving tools provided by these three theories. Access has been gained into the facts about the organizational design of Wal-Mart by conducting interviews with three senior level managers in charge of organizational structure. Basically, the design of Wal-Mart, as an organization, is that of a divisional structure. It has different divisions like, Wal-Mart Realty, Wal-Mart International, Wal-Mart Specialty Stores, Sam's Clubs, and Supercenters which are separate and partially autonomous units. Each division has its own specific set of goals. Step-2 The three theoretical frame works selected for this paper are chosen based on the advantages they have in addressing the specific issue in focus. For example, most of the complaints against Wal-Mart that have led to legal litigations and negative publicity has been regarding labor issues and hence a worker-centered approach put forward by Roethlisberger and Dickson (1943) can help re-model the organization’s functioning in such a way as to avert this criticism. Similarly, the socio-technical theory of Pasmore ((1988, p.87-109) and the contingency theory by Hellriegel and Slocum (1973) have their focus on the environmental aspects of an organization, which can be applied in the case of Wal-Mart which is haunted by many a social conflicts. Neoclassical theory of Roethlisberger and Dickson (1943) has as its core focus, the relationship between â€Å"working conditions† and â€Å"employee efficiency† (p.1). Through an experiment, Roethlisberger and Dickson (1943) had proven that there was a connection between better working conditions and better performance. In this way, this theory had changed the essence of organizational theories evolved thus far by replacing the mechanistic views by a more humanistic worker-oriented view. This theory had asserted that: An individual is not a mechanical tool but a distinct social being, with aspirations beyond mere fulfilment of a few economic and security works. Individuals differ from each other in pursuing these desires. Thus, an individual should be recognized as interacting with social and economic factors (NRMED-FAO, n.d.). Participative management has been another aspect of this theory, whereby employees are given an appropriate role in the decision making process (NRMED-FAO, n.d.). Any application of the neoclassical theory has to be by keeping in mind, the existence of an informal organization within any formal organization, the socio-psychological factors that influence workers, the inherent illogi cality of human mind, the two-way flow of communication within the hierarchy, and the need of teamwork (Pradeep, p.295). Socio-technical theory of Pasmore (1988) has based all its assumptions on the fact that â€Å"every organization consists of the people, the technical system and the environment† (NRMED-FAO, n.d.). In this theory also, the importance of considering workers a human beings and all the more, social beings, is stressed (Pasmore, p.5). It has been observed that what is meant by an organization is actually an agreement, a contract between and among people and â€Å"changes in the organization will affect this agreement and vice versa†

Will a new economy lead to new attitudes Essay Example | Topics and Well Written Essays - 250 words

Will a new economy lead to new attitudes - Essay Example The introduction of new technologies had replaced many manufacturing processes done in 1930s. Under the present economy, new industries are introduced, jobs are created, wages and income increase and skills are honed. New industries gives new jobs, new technologies and provide new ways or organizing works that have changed work patterns in many existing jobs. As business becomes high tech, goods and services are more innovative and production grows to be flexible, attitude of people becomes to be more conscious of efficiency and productivity. Wherein before, there is a perception that it is difficult to make business in other parts of the world, now the world becomes our next door’s neighbor. As the IT brings in development of trade toward globalization, the new attitude is that of being innovative to become competitive and having a strong disposition to compete in global business world. (â€Å"The new economy index†) In conclusion, new attitude developed by the new economy are the outlook towards global competitiveness, that of being responsive to technological change, manners in business, mind-set of being efficient and innovative in the light of the fast pace of economic

Story telling Essay Example | Topics and Well Written Essays - 500 words

Story telling - Essay Example The memories of my childhood days are nostalgic especially those with my grandfather. He is a man I will never forget for the positive impact he had in my life. In his young days, he was a pearl diver and later a fisherman. My grandfather was a man on his word and kept all the promises he made and only talked when he had something to say. He taught me on how to become a good listener and only talk when it is important. Ali was a strong man who was married to only one wife, twelve children, six boys and six girls. He wanted a great future for his children and that is why he ensured that they acquired education. According to Ritchie (27), education was not a priority during those days but my grandfather had a mindset of earlier generations. Staying around my grandfather impacted positively in me as I realized the value of education and being aggressive towards achieving my life goals. My grandfather had a unique way of showing love. He had an exemplary way of loving his wife and children. He loved me so much and always wanted to have me around when doing his work. He always said that he didn’t want his grandchildren to grow into lazy adults. He also trained his children to become independence so that they could be successful in life. My grandfather contributed a great deal to what I am today. I am able to love my family and take care of them just like my grandfather did. My grandfather had a character of not holding back in anything that came his way. He taught me to always go for what I want and never give up easily in life (Ritchie, 31). This is a character that I have always upheld even in my education, as well as, in all my workplaces. He described a person who gives up easily as a failure and that they will never be successful. In conclusion, the experience I always had with Ali was that it is important for any child to have a grandfather. His demise affected me strongly and still affects me to date. He was a friend and grandfather I will never

Mother daughter relationship in Mary Gordon's Cleaning Up (short Essay

Mother daughter relationship in Mary Gordon's Cleaning Up (short story) - Essay Example ut working for what you receive; therefore, Loretta never bathes for fear that she would be â€Å"putting herself in the camp of the Lavins’ children† (p. xx). Although she doesn’t like children, she makes an effort to engage herself in play with the oldest child, John Lavin, as her way of â€Å"pa[ying] her board† (p. xx). She knew her mother would have expected this of her. Although it is never written that the Lavin family is anything but accommodating during Loretta’s stay, Loretta constantly feels like an outsider. She is convinced that her mother’s actions caused Martine Lavin, the matriarch of the family, and other community members to see her as an inferior person. Later, when she becomes a well-educated woman, she still feels that her old community would condemn her because of her mother’s earlier behavior. â€Å"Cleaning Up† is, in parts, consistent with Gordon’s life. In the story, Loretta attains the same leve l of education that Gordon currently has. Loretta’s pre-college schooling is better than what Gordon was provided, but both earn a Master’s degree and use it to teach. Mother Perpetua is Loretta’s greatest influence. According to an Internet biography, Gordon received the same kind of influence from Elizabeth Hardwick and Janice Thaddeus. Gordon actually considered becoming a nun, a lifestyle that Loretta also briefly contemplates. Finally, Loretta’s work ethic is similar to Gordon’s. Gordon worked to support herself, just like Loretta. Against her mother’s advice, Gordon performed secretarial work and babysat for Thaddeus to put herself through school. Gordon’s own mother, though disfigured from and afflicted with polio, also worked as a secretary to support her family because her husband wouldn’t. The fact that Loretta strives as hard as her mother would have wanted her to, makes it clear that Loretta loved her mother despite the turmoil she’d created. Even though Loretta never saw her mother again, she thinks about

Relativism and Morality Essay Example | Topics and Well Written Essays - 750 words - 1

Relativism and Morality - Essay Example From this research it is clear that violation of another human being and to society with the taking of a life is universally wrong; it cannot be comprehended nor excused except in very few cases where violence begets violence. Warfare and the making of war between factions can be said to be racially motivated, territorial motivated, self-interest motivated, religiously motivated and politically motivated. None of these reasons present a strong enough argument to be the deciding faction which starts a conflict such as war. Responding in like becomes a very difficult position to be in for all of society. Taking quick action such as Goodman suggests would seem to be the best choice to avoid the mass murder of millions in a tense situation but look how we have responded to 9/11, a conflict that is still going on despite the death of the leader the United States initially sought. War unites and disunites people unlike any other act. Terrorist usually have a purpose or message behind their violent acts of destruction though these messages and purpose are immediately discounted when the act becomes violent and takes human lives that should be valued above all other considerations. Terrorism uses media sensation to gain national attention to a group or faction self-interested purpose, policy, religion, or idea. Media must take some responsibility in ascribing so much coverage and attention as to elicit repeats of similar behavior though citizens want to know what is going, regardless of their opinion on the issue. By our very actions we further feed the terrorist’s actions and it is a repetitious cycle.... Terrorist usually have a purpose or message behind their violent acts of destruction though these messages and purpose are immediately discounted when the act becomes violent and takes human lives that should be valued above all other considerations. Terrorism uses media sensation to gain national attention to a group or faction self-interested purpose, policy, religion, or idea. Media must take some responsibility in ascribing so much coverage and attention as to elicit repeats of similar behavior though citizens want to know what is going, regardless of their opinion on the issue. By our very actions we further feed the terrorist’s actions and it is a repetitious cycle. Human trafficking and slavery are just as deeply wrong, though I would imagine for the one being enslaved there must be periods of time that are so hateful that they are only thankful to be alive and not much else. It is pointed out that drugs, which are extremely scrutinized and resisted by the United States are sold merely once, while human beings can be sold repeatedly. Incest and human trafficking are to a much greater degree fundamentally wrong while polygamy can be situational. I disagree with Goodson’s views in this area, he uses the statement that polygamy diminishes intimacy and trust and transforms the nature of marriage which I believe that once again he is relying on language and communication as relationship factors, and societal standards which as his whole paper describes are obviously seriously out of order and frequently wrong because as a society we are extremely divide. I do not feel it is a morally wrong act to be a polygamist unless it involves minors marrying or situations that preclude to incest or child endangerment. Rape and clitoridectomy distorts

Roman Empire Essay Example for Free

Roman Empire Essay The world of Literature before 1500 AD encompassed the era from the day when the civilizations came into existence till AD 476, when Roman Empire fell and again from the Florentine Renaissance in late 15th century to the renaissance. The literature saw the growth in the lands of Hebrews, Greeks and Romans who made remarkable contributions in poetry, and drama form. The ancient Greeks in the period from 356 BC to 323 BC formulated their work on basis of the works of the well-known and famed Pericles, Plato, and Aristotle using politics and philosophy as their tools under the leadership of Alexander, the Great. In the same way, Hebrews exerted an enormous impact on world history through their holy book, the Bible, which is still considered sacred by both Jews and Christians. Fragments of the literary works in the ancient era were discovered in nineteenth century â€Å"Beowulf,† the Norse sagas, the â€Å"Kalevala,† the â€Å"Nibelungenlied,† the â€Å"Song of Roland. † Starting g from 2700 B. C and written uptill 2000 B. C, Gilgamesh was the first great heroic narrative. It was lost due to the vagaries of time but it was found again in 1872, and its importance came to be known when the Utnapishtims Story of the Flood, was rediscovered. Gilgamesh is a Saga of spirituality, and the psychology of character is embodied in the character of Gilgamesh who took upon the journey to attain immortality, but he found his journey was fruitless and he lamented, â€Å"For whom have I labored? For whom have I journeyed? For whom have I suffered? I have gained absolutely nothing for myself, I have only profited the snake, the ground lion! † (angelfire. com, online edition) He realized that death was inevitable and should make most of the short life. The literature came into prominence in the Western world in 100 AD. The earliest of the medieval literature were Epic poems in vernacular language depicting the heroism, myths and supernatural elements derived from oral tradition. Beowulf is a good example of an Old English heroic elegy, written in 700-750. It has 3,183 lines. It is originally Anglo-Saxon poetry but created an indorrebale influence on the literatures of the generation ahead and had become â€Å"England’s National Epoc†. The poem composes of legends. Beowulf, a hero of the Geats, fought battles with three antagonists; Grendel who was always destroying Heorot, its inhabitants in Denmark, Grendel’s mother and later a dragon. Between the years 1340 to 1400 was the age of Chaucer. His period was the age of transition, as this age saw the meeting of the two incongruous periods-the medieval and the modern or the Renaissance. The most crucial aspect of the medieval period is the belief in spirituality and abstract ideas, whereas the Renaissance period believed in sensuous and the concrete. Medieval period supported communism whereas Renaissance supported individualism. Medieval mind never tolerated free thoughts whereas the period of Renaissance advocated individualism. Chaucer represented his own age and held the mirror to the life of his time. He was truly the social chronicle of England during the same period. His poetry is a reflection of the fourteenth century not in fragments but as a whole. Other poets of this age focused on certain aspects prevalent at that time for e. g. anonymous author of Pearl tells us about the mysticism of the refined minds. Wycliff gave us the surging wave of religious reformation, but Chaucer focused on wide and variegated life. Chaucer symbolized the Middle Ages and poster the spirit of medieval world but underneath him flowed the spring of Renaissance. Writers of medieval period captured the foibles and follies of the contemporary society in the mysticism nature. Chaucer also used Nature in its full as symbol of life, which is fresh and serene and stirs up the emotion of erotic love in his most enduring and popular â€Å"The Canterbury tales. † The Canterbury Tales begins with the season of spring in the month of April when the flowers are in full bloom, the birds are swinging from the trees and giving the chirping sounds, which is a symbolic of spiritual renewal. Spring also is a symbol of erotic love and we can have an essence of it in a scene when Palamon looks at Emelye, who is gathering fresh flowers to make garlands in honor of May and the Squire too participates in the beauteous and ardent scene of love. His courtly love signifies the freshness of the month of May. In the General Prologue, the garments are also symbols signifying characters personality and reveal the true nature of characters. The rich silk and fur gown, which the Physician’s is wearing shows his love for wealth and the flower brocade on the tunic of the Squire shows his youthful vanity and the forked beard of the Merchant symbolizes his duplicate nature. Chaucer also used physiognomy to decipher the temperament of pilgrims in the general prologue. The peasants are shown with the exaggerated figures. And the best example is Miller, who has round and ruddy face with a wart on his nose. Chaucer rendered meritorious service to the English language and made it an instrument of social, political and literary thought. Chaucer was realistic too as he revealed the truth as he saw it, which he showed in the journey of pilgrims to the holy shrine in this Canterbury Tales. He imparts the solid touch of realism as he portrayed in this characters. With him the literature also saw the beginning of realism in the new emblem and thoughts. The prose literature was almost negligible. Its bulk was very small and the literary quality was also very less. Though in France and Italy prose writing was in full swing, the English prose was very slow to catch up. Before 1350, there was hardly any prose work written except Ancrene Riwle. It is spiritual and the characteristic of Anglo-Saxon is clearly visible in their works. Higden, a monk wrote Polychronicon in Latin in 1350. In this work, we can find the reflection of the history of the entire world from the early creation to Higden’s own times. By the end of the century, Walsingham of St. Albams compiled Latin chronicles, which are similar to the description of scenes in the pages of Forissart. John Trevisa translated Higden’s Polychronicon and completed in 1387. Chauser’s contribution towards the English prose is also worth noting but he was more of a translator when he wrote prose. His prose works include the Treatise on the Astrolabe, the translation of Boethius. The most valuable contribution was the addition of the new prose in meters, which had not yet appeared before and added the beauty of Boethius. The Astrolabe is an early scientific treatise and an address to â€Å"Little Lewis My son†. This treatise amplifies the scientific application of literature and the literary handling of Science. The contemporary to Chaucer, there were other three chief writers. One was John Gower, who was a wealthy landowner whose tomb with his effigy is placed in St. Saviors, Southwark. Gower was conservative and he focused more on the past then on the future. The large part of his works was written in French and Latin. In his â€Å"Vox Clamantis† (The Voice of One Crying in the Wilderness), he denounced the common people for their revolt against the privileged class and the people of authority. And in this vocabulary, he showed exaggerated bitterness. After the death of Chaucer in 1400 for complete 150 years, there was no great writer and the main cause for the decline of the literature was the restart of the Hundred Years War, and then the War of Roses, which was nothing more than the butchery of rival factions. In this period, the leading poets were only imitators of Chaucer and many of them were Scots. Among them was the Scottish king, James I who wrote beautiful poem â€Å"The king’s Quair†, which is more of an allegory of 1400 lines showing the love of an captive author with a lady who promised to bring him out from the drudgery to the life of riches. This was the historical and the biographical account of his own eighteen years captivity in England. He incorporated the Chaucer’s stanza of seven lines riming ababbcc, which gave him the name of ‘rime royal. ’ (Fletcher, 1918) The most popular were the ballads written by both the English and Scottish writers. Among all the best ballads written are: The Hunting of the Cheviot, Sir Patrick Spens, Robin Hood and Guy of Gisborne, Adam Bell, Clym of the Clough, and William of Cloudeslee; Captain Car, or Edom o Gordon and King Estmere among the few. The ballads, as the old tradition dictates, give the vivid, picaresque and descriptive account of the battles of the Kings and knights. The Author of Par excellence, which fifteenth century saw was the Sir Thomas Malory. His main purpose was to gather important works of Arthurian romance and organize them giving the historical accounts of King Arthur and his knights in his book ‘Le Morte Darthur,’ The Death of Arthur. It was the first English classic, which was published and printed. Women in the medieval period were not treated equally to men. They were mostly religious writers who were canonized as nuns like Clare of Assisi, Bridget of Sweden and Catherine of Siena, who wrote their experiences and insights into religion. But what ever they wrote, they gave charm and feminine touch to their works and in the secular realm, opportunity came in form of Marie de France and Christine de Pizan and from their soul flowed their repressed feelings. They wrote on courtly love. Marie de France was born in France but lived in England in 12th century. In most of her manuscripts are found the characteristic features of Anglo-Norman. The medieval French literature is abounding with stories of courtly love focusing on the queen. The queen for the literary world is the â€Å"natural feminine object of male heterosexual desire†(Kinoshita, Online Edition) and she remains a figure of desire in the hands of King but the Marie de France’s Equitan1 tells us the story of king’s extra marital affair with Senechal’s wife. Even though the lady resisted but she succumbed to his advances and the two plotted to kill Seneschal so they both could marry but Seneschal knew about their disloyalty and he blistered them to death in hot bath and the moral she poster is: â€Å"He who plans evil for another may have that evil rebound back on him† â€Å"Tels purcace le mal dautrui / Dunt tuz li mals revert sur lui† (309-10). 4 (Kinoshita, Online Edition). What lie beneath are the complexities abounded in the courtly forms and the responsibilities of the king? Equitan1 tells about the function of kings, and the principal element is the lord-vassal relations. The feminist theories of today looked into the various aspects that constituted the feminine role in the medieval age and subsequently in their literature. There were very few female writers who had really left an endurable mark on the society. In the patriarchy society, they enjoyed respectable and encouraging social circumstances, though for a limited period. Writers such as the Greek poet Sappho, the Alexandrian mathematician and philosopher Hypatia, and the Chinese scholar Pan Chao (Ban Zhao), were the women of great intellectual abilities. Hypatia was born between 350 and 370 AD. She was a mathematician and also taught astronomy and astrology. She was daughter of Theon, a philosopher and a student in a school of Plato and Plotinus. Her notable works are commentaries on Diphantus’s Arithmetica, on Apollonius Conics and Ptolemy works, but all are lost. She was murdered in 415 AD by Christians mobs. With her murder her works too died. The role of the women was just confined to the domestic affairs which is reflected in the art and literature of the time from Athenian vase paintings to the Homeric verses in both Iliad and Odyssey. In the epics, the woman got the place as mythic figures. Ovid in his Metamorphoses recapitulated women as goddesses who had the power to revenge, as revengeful queens, and on the other hand the cunning witches, and the objects or victims of male aggression and sexual desires. In the classical dramas of Aeschylus, Euripides, Aristophanes and Sophocles, women looked in a different way. Clytemnestra kills the king; her husband Agamemnon but does not hide instead proclaims her deed openly. Agamemnon had killed his only child as he deemed it necessary but Clytemnestra did not forget it and revenged her death. Here Aeschylus poses ethical question on viewers and makes the reader feel sympathetic for women, a thing, which could not be heard, in the contemporary society and Aeschylus bestows on her with title of tragic heroine. On the other hand, Euripides is seemed to be afraid of women. His protagonist Medea is depicted more as a devil than a human being that came on this earth from some other world. She has barbaric attitudes. Euripides was fully aware of the fact that the majority of the women are sensitive human beings, but he was looking at the other side of the women who in the Athenian Age had no rights like that of men and are different than men and when the time came, they are capable to be barbaric too. In Bible, women are shown as heroic female figures like Esther and Judith mostly found in the Old Testament Apocrypha. And the Bible also shows women symbolically as the two opposite poles: temptress Eve and the flawless Virgin Mary. Chaucer in his Canterbury tales presented the women as a dominating personality. Though Chaucer presented the follies of both men and women, he yet gave women her place in the society. In the Knight’s Tale, women find themselves free from the male domination. Emily, Duke Theseus’ sister-in-law, refuses to marry as she considers her chastity as most valuable. His cousins, Palamon and Arcita, both fall in love with Emily. Palamon loves Emily because he thinks that she is a goddess Venus, â€Å"goddess/ But [she] is really Venus [to him]† (Chaucer 1986) whereas Arcita loves Emily because he finds her most beautiful, â€Å"Beauty [that is] so fresh it destroys [him]† (Chaucer, 1986) The plays during the Middle Ages were liturgical, mystery plays but they did not get its due place in the society, and most of the plays had religious fervor. Slowly the mystery plays got popularity in the fourteenth and fifteenth centuries with the most renowned and passionate play being Oberammergau. Along with this, morality plays also gained popularity. Twenty years later, people began to watch the Chronicle-History plays. These forms of the plays depicted the glory of the English to inculcate among public, the feeling of pride under Elizabeth and an ardent desire to know the historical past. The plays became popular, as there was an enthusiasm among the people due to the defeat of Armada in the struggle with Spain. After that there was an era of Renaissance, the freshness of the new ideas originated from the new order in the social, political, economic fabric of the society. Reference List Angelfire. com The Epic of Gilgamesh Retrieved on September 10, 2007 from W. W. W: http://www. angelfire. com/mo3/paganfiles/library/ancient/epic_of_gilgamesh. txt Chaucer G. (1986) The Canterbury Tales. Oxford World’s Classics. Oxford: Oxford University Press Inc. Fletcher R H. (1918) A History of English Literature. Retrieved on September 10, 2007 from W. W. W: http://classiclit. about. com/library/bl-etexts/rfletcher/bl-rfletcher-history-3. htm Kinoshita S. Adultery and Kingship in Marie de Frances Equitan1. Retrieved on September 10, 2007 from W. W. W: http://www. luc. edu/publications/medieval/vol16/kinoshta. html

Effect Of Substrates On The Respiration Of Yeast Biology Essay

Effect Of Substrates On The Respiration Of Yeast Biology Essay The aim of this investigation is to examine what effects different substrates have on the respiration of yeast. I will investigate this by measuring the amount of carbon dioxide evolved during anaerobic respiration. Pilot Experiment: Before we could test which carbohydrate and type of yeast produced more carbon dioxide, we had to standardise the other variables of this experiment; temperature and concentration. Therefore, in order to find the optimum conditions we carried out a pilot experiment. In this experiment we used a range of temperatures from 10ËÅ ¡ to 60ËÅ ¡C and three different concentrations of carbohydrate 1%, 5% and 10%. The experiment was carried out as a group experiment with everyone being allocated a different temperature and concentration to test. It was carried out over a standardised period of 5 minutes. The rationale for conducting this pilot experiment was that enzymes are biological catalysts that are made up of globular proteins which are activated to work by temperature. They exist in the yeast and our bodies and therefore work best at 40ËÅ ¡C, however, they denature soon after and so our body temperature is kept at 37ËÅ ¡C to ensure this does not happen. Denaturation is the irreversible loss of 3D structure of enzymes and can be caused by excess heat or a change in PH. According to the Collision theory however, in order for a reaction to take place a certain level of energy, called the activation energy, must be reached. This energy needs to be reached by the particles colliding in the right way and fast enough, so a reaction can take place. By giving the particles more energy it encourages more to collide therefore the activation energy can be reached and a reaction can happen. The kinetic theory explains the effect of temperature, volume and pressure on the number of collisions. The theory states that if temperature is increased the particles gain more energy and there are more collisions in a given time. Similarly, increasing the concentration means than there is a higher chance of a collision happening because there are more particles in a given volume. If the concentration of carbohydrate/yeast is increased there are more enzymes known as z ymase, produced. This means there are more active sites for the carbohydrate substrate to attach to and the reaction happens faster. Therefore a balance must be reached between temperature so it does not denature the enzymes but is high enough to activate a reaction. Also, having a highly concentrated solution is seemingly advantageous but this can cause osmotic problems, so another balance must be reached, as to avoid this problem, but not to discourage a reaction. Apparatus: Beehive shelf Clamp Stand 50ml conical flask Trough Clamp Thermometer 50cm3 measuring cylinder Heat proof mat Spill 500ml beaker Bunsen burner Delivery tube with bung Tripod Gauze Stopwatch 25cm3 of bakers yeast 25cm3 of sucrose Electronic water-bath Method: 25cm3 of bakers yeast and 25 cm3 of sucrose was mixed together and preheated at the required temperature for 15 minutes in an electronic water-bath. 400cm3 of water was preheated to the same temperature as the yeast using the Bunsen burner. The trough was filled with water and a measuring cylinder was inverted by filling it with water then pressing a piece of paper onto the top to prevent any air bubbles from getting in. The beehive shelf was placed in the centre of the trough and the measuring cylinder was clamped in place, with the top resting on the beehive shelf, the hole being directly under it. The yeast was placed in the preheated water-bath and the bung from the delivery tube was replaced. The delivery tube was inserted into the hole in the side of the beehive shelf and the stop watch was started. Thirty seconds was timed then the beaker with the yeast/carbohydrate mix was swirled for 5 seconds to mix the yeast/carbohydrate. This was repeated every thirty seconds for fifteen minutes, with readings being taken at three five minute intervals. The correct temperature in the water bath was maintained by adding more hot water to it throughout the experiment. BACKGROUND INFORMATION: YEAST Saccharomyces cerevisiae, also known as yeast, is a micro organism that uses saprophytic digestion to break down substrates. This is achieved through releasing specific enzymes to break down specific substrates, but if yeast does not contain a certain types of enzyme then it cannot break down its substrate. The more the enzyme of a particular substrate, the faster the rate of breakdown and therefore the more CO2 is produced. This will help me to test how much CO2 each substrate produces. Yeast can also respire aerobically and anerobically depending on the availability of O2. If there is plentiful of O2 then yeast would respire aerobically with sugars, producing H2O and CO2 as waste products. However, if no oxygen is available then the fermentation would occur which converts sugars into CO2 and ethanol. RESPIRATION Respiration is the process by which energy is released energy from glucose in the presence of Oxygen, forming carbon dioxide and water as waste products. Glucose releases energy in a series of reactions that take place inside components of the cell. The stages are briefly explained below: GLYCOLYSIS To get the sugar in a more reactive form it is produced to fructose-1,6-bisphosphate by the addition 2 phosphate molecules. This process is a phosphorylation reaction. The fructose-1,6-bisphosphate is then broken down into 2 molecules of glyceraldehydes-3-phosphate, which comprises of 3C each. The glyceraldehydes-3-phosphate converted into pyruvate via the oxidation process where each GAL3P molecule releases 2 hydrogen ions and 2 electrons. The electrons are then transferred to NAD to produce NADH (reduced NAD) and the energy is used to produce 4ATP from 4ADP and 4Pi. Finally there is a net yield of 2 molecules of ATP, and 2 molecules of pyruvate which is used in the link reaction and 2 molecules of reduced NAD which carries on to the link reaction. LINK REACTION In the link reaction the 2 molecules of pyruvate leave the cytoplasm of the cell and enter the mitochondrial matrix. This is an oxidation reaction where 2 NAD molecules oxidise 2 pyruvate molecules into 2 acid molecules. These 2 molecules of acetic acid then go on to combine with 2 coenzyme-A molecules to form Acetyl Co enzyme A. in the end of this stage 2 molecules of reduced NAD form, 2 molecules of CO2 is lost and most importantly, Acetyl Co enzyme A is formed through the conversion of pyruvate. This is then used in the next stage of respiration. KREBS CYCLE At the start Acetyl Coenzyme A , combines with Citrate Synthase an enzyme as well and a 4 carbon molecule called oxaloacetate, forming Citrate. Then, Citrate goes through the process of oxidative decarboxylation which forms a 5 carbon molecule called oxoglutarate.at this point NADH is produced and CO2 is removed. In the latter stages of the krebs cycle, the oxoglutarate is changed into a 4 carbon oxaloacetate molecule. NADH is made and 1 molecule ATP is also made. The volume of CO2 that is produced in the krebs cycle is important as this is the dependant variable. ELECTRON TRANSPORT CHAIN In this stage all of the NADH and FADH that has been produced in the previous stages is converted into ATP. This takes place in the cristae of the mitochondria. The NADH and FADH electrons move. When the electrons pass from one carrier to another, a series of reduction and oxidation reactions take place which releases energy in the process. This energy is used to pump H+ ions from the matrix into the intermembrane space, thus creating a gradient where the concentration of the H+ ions in the intermembranal space is higher than it s in the matrix. The inner membrane contains enzymes called ATP Synthase and The H+ ions diffuse through these enzymes causing energy to be released which is used to synthesise ATP through phosphorylation. The process is called because the final terminal electron acceptor is oxygen which picks up the electrons from the chain and the H+ ion from the matrix to form H20 as a waste product. This reaction is catalysed by the enzyme Cytochrome Oxidase For every NADH which enters the chain and is oxidised by NADH dehydrogenase, 3 ATP are produced. For each FADH that enters the chain, 2 molecules of ATP are made. ENZYMES Enzymes are proteins that can effectively increase the rate of a reaction by lowering the required energy (activation energy) needed in order for the reaction to occur. Enzymes have a tertiary structure which decides the shape of the active site. The substrate must be specific to the active site because if they were not complementary to each other, then the substrate can no longer bind to the active site, thus the enzyme substrate complex does not form. The performance of enzymes can be affected in several ways some of which I have explained below. TEMPERATURE An increase in temperature will cause an increase in the rate of reaction because both the enzyme particles and substrate particles have gained kinetic energy. This will result in the particles to move faster, thus increasing collision frequency and the numbers of successful collisions as the particles have the required activation energy. If the temperature rises above the optimum temperature then the enzymes can become denatured. This happens because the enzyme molecule vibrates more causing the weak hydrogen bonds (holding the 3D structure of the enzyme together) to break. This eventually leads to the shape of the active site being altered. Consequently, the substrate will not be able to bind with the substrate as the shape of the active site is no longer complementary so the substrate enzyme complex can not form. This is important in my experiment because if the yeast (enzyme) was to become denatured then it would not be able to bind with the substrate (e.g. glucose) and the react ion would not be catalysed, preventing any CO2 from being formed. I must ensure that temperature is kept constant throughout. PH Another factor which can affect enzymes is pH. Enzymes also have an optimum pH which is pH enzymes work best at. Changing the pH can change the tertiary structure due to the number of H+ ion in an acid or the OH- ions in an alkali. These ions disrupt the hydrogen and ionic bonds between -NH2 and -COOH. This will cause the tertiary structure to break down and changing the active site in the process. Once again, the substrate will no longer be able to bind with the active site, hence no substrate enzyme complex will form. I intend to use a buffer solution which will resist any changes in pH. SUBSTRATE CONCENTRATION Increasing substrate concentration increases enzyme activity as they are more molecules to occupy the active site, thus a faster reaction. If more enzyme substrate complex forms then more CO2 will be produced. However this is occurs only for a certain period until all the active sites are saturated with substrates. Therefore an increase in substrate concentration will not result in a increase in the rate of reaction. Carbohydrates such as glucose and sucrose are too soluble and reactive to be stored as they come as they would present osmotic problems and so they are stored in much more complex, insoluble structures known as polysaccharides. Polysaccharides are macromolecules formed by the joining of many monosaccharides together in condensation reactions. There can be more than 3000 repeating units in a chain, joined by glycosidic bonds, forming many complicated structures, one being starch. Starch is a polymer of alpha glucose, where the hydroxyl group is below the ring, and is made up of 30% amylose and 70% amylopectin. Amylose is a long polymer consisting of over 300 monomers joined by 1,4 glycosidic bonds. Amylopectin gives starch its compact store of energy property as it consists of monomers of glucose in 1,4 and 1,6 linkages causing the chain to branch out. Amylopectin can contain several thousand monomers and forms a coiled up structure which is a valuable store of energy for living organisms. Starch is suited to storage as it is insoluble in water and therefore cannot move out of the cells during osmosis. However, it can easily be broken down to produce simpler carbohydrates by a hydrolysis reaction via the enzyme zymase produced by yeast. It is broken down firstly into maltose then into glucose then into carbon dioxide and ethyl alcohol. In this experiment we used two different types of the Saccharomyces Cerevisiae (saccharo meaning sugar and myces meaning fungus) sub- species of yeast to respire the carbohydrates; bakers and brewers. Both are made up of small cells, separated by walls of cellulose with a living organism inside called a protoplasm. Yeast cells reproduce by budding, and do so every two to three hours under ideal conditions. All types of yeast will respire carbohydrates to make energy in order to reproduce. Therefore, when sugar is added to the Brewers yeast, the yeast cells secrete the enzyme zymase to begin respiring the carbohydrate substrate according to the following equation: C6H12O6 + 6O2 = 6CO2 + 6H2O + 2900kJ Glucose + Oxygen = Carbon + water + Energy dioxide This is known as aerobic respiration due to the presence of oxygen, (defined as free or molecular oxygen atoms participating in the respiratory breakdown of organic substances). Brewers, however, are more interested in anaerobic respiration, (defined as when the respiratory breakdown of organic substrates takes place without the participation of free or molecular oxygen atoms). In yeast, anaerobic respiration is sometimes called fermentation. This happens when the enzyme secreted by yeast, known as zymase, catalyses the break down of glucose to produce ethyl alcohol, in abundance and less carbon dioxide, (which they use to create the fizz). It happens that starch is broken down to form maltose, maltose is broken down into glucose and glucose breaks down according to either the aerobic or anaerobic respiration equation, depending on the conditions. Therefore, Brewers use anaerobic (airtight) conditions and most of the reaction happens according to this equation: C6H12O6= 2C2H5OH + 2CO2 + 84kJ Glucose = Ethyl + Carbon + Energy Alcohol dioxide This produces the desired product i.e. the alcohol and the bi- product of carbon dioxide, which we collect in this experiment. The Bakers yeast is very similar to Brewers except it is used for a slightly different commercial purpose i.e. bread making. The yeast respires aerobically in this process as the main function is to inflate the dough to make it softer, and therefore, the desired product comes from the first equation: C6H12O6 + 6O2 = 6CO2 + 6H2O + 2900kJ Glucose + Oxygen = Carbon + water + Energy dioxide The reaction also requires nitrogen from the air to act as a nucleating site for the carbon dioxide to form bubbles against and therefore produces a good yield of carbon dioxide. In most processes where yeast is used, it will have been cultivated to suit that purpose, e.g. to produce more carbon dioxide or more ethyl alcohol, therefore there will often be a big difference between the behaviour of the two yeasts. We can test this in this experiment as the variable of the condition (whether it is in aerobic or anaerobic conditions) is being standardised by both the experiments being carried out in aerobic conditions. This is due to the fact that there is a good oxygen supply whilst the yeast is preheated and during gas collection, when the system is air tight, it is not left long enough for it to use up the oxygen and respire anaerobically. This is a favourable condition for maximum CO2 production however as, according to the equation, there are six moles of CO2 produced aerobically and only two moles of gas produced anaerobically. Aim: The aim of the pilot experiment is to investigate the optimum temperature and concentration of carbohydrate, that, when respired with yeast, produces the biggest volume of carbon dioxide. PLANNING: THE DEPENDANT AND INDEPENDENT VARIABLE: The dependant variable will be the volume of C02 produced during respiration and the independent variable will be the substrates that I decide to use in the experiment. These are Glucose, Fructose, Maltose, Lactose and Sucrose. NULL HYPOTHESIS: The type of carbohydrate being respired will have no significant effect on the amount of carbon dioxide produced in a given time. HYPOTHESIS: In accordance with the information that has been gathered, the following hypotheses were derived; Hypothesis one: When respired by yeast, different types of carbohydrates will produce different amounts of CO2. I believe this because glucose is a monosaccharide which consists of one molecule, sucrose is a disaccharide, which consists of two molecules and starch is a polysaccharide, consisting of many molecules. This means they all have different molecular structures and therefore will break down with different levels of ease. In order to keep an open mind however, the following null hypothesis was also noted; Null hypothesis one: The type of carbohydrate being respired will have no significant effect on the amount of carbon dioxide produced in a given time. The second hypothesis was theorised relating to the variable of the yeast: Hypothesis two; Different types of yeast will produce different volumes of CO2. I predict this because the commercial purposes of Bakers and Brewers yeasts are different and therefore special cultivations might have made the yeast better designed for one purpose than the other. Again a null hypothesis was also adopted; Null hypothesis two: There will be no significant difference between the amount of carbon dioxide produced by the Bakers and the Brewers yeast. Apparatus: The following apparatus will be used when conducting the experiment: Beehive shelf Trough 200cm3 measuring cylinder 500ml beaker Tripod 25cm3 of bakers yeast 25cm3 of brewers yeast 25cm3 of sucrose 25cm3 of glucose 25cm3 of starch Bunsen burner Gauze Heat proof mat Rubber tubing 50ml conical flask Thermometer Spill Delivery tube with bung Stopwatch Clamp Clamp stand METHOD: 25cm3 of the desired yeast and 25 cm3 of the desired carbohydrate was mixed together and preheated at the required temperature for 1 hour in an electronic water-bath. 400cm3 of water was preheated to the same temperature as the yeast using the Bunsen burner. The trough was filled with water and a 200cm3 measuring cylinder was inverted by filling it with water then pressing a piece of paper onto the top to prevent any air bubbles from getting in. The beehive shelf was placed in the centre of the trough and the measuring cylinder was clamped in place, with the top resting on the beehive shelf, the hole being directly under it. A small piece of rubber tubing was inserted into the beehive shelf through the hole in the side, up into the inverted cylinder, and the other end was attached to the delivery tube. The yeast was placed in the preheated water-bath and the bung from the delivery tube was replaced. The delivery tube was inserted into the hole in the side of the beehive shelf and the stop watch was started. Thirty seconds was timed then the beaker with the yeast/carbohydrate mix was swirled for 5 seconds to mix the yeast/carbohydrate. This was repeated every thirty seconds for fifteen minutes, with readings being taken at three five minute intervals. The correct temperature in the water bath was maintained by adding more hot water to it throughout the experiment. This was repeated using each different type of sugar with each different type of yeast: Bakers glucose, Bakers sucrose, Bakers starch, Brewers glucose, Brewers sucrose, Brewers starch. Control of the variables of the method: In order for this experiment to be run fairly there are certain controls that should be taken into consideration: -The temperature must be kept constant by refilling the water bath with warm water. -The yeast/carbohydrate solution should be pre-mixed and preheated for the same amount of time i.e. one hour, in each experiment. -The gas should be collected at three 5 minute intervals for each condition. -The solution should be swirled every thirty seconds for five seconds to mix the yeast and carbohydrate together. -The temperature and concentration should be the same for each experiment; 35ËÅ ¡C and 7.5% respectively. -The amount of yeast to carbohydrate should be kept constant i.e. 25cm3 of each. -The same method should be used; the rubber tube, collection of gas in an inverted measuring cylinder, as certain ways are more accurate than others. Control of the measurements: When taking measurements, the following points should be noted: -When measuring the gas, measure to the bottom of the meniscus of the water. -Make sure the measuring cylinder is perpendicular to the clamp stand to ensure that the water lies at the correct level. -When timing, do not shake at 30 seconds by the stopwatch because 5 seconds is added on each time (while it is shaken) and therefore by the sixth minute or so it will require shaking as soon as it has been shaken. -Keep a constant check on the thermometer to ensure the temperature does not drop. Results: A summary table to show volume of gas produced by bakers and brewers yeast with three different carbohydrate substrates: Amount of CO2 produced in cm3 in fifteen minutes in each condition The table above shows the results of our practical, including my own, highlighted in blue. The average volume of gas collected in each separate condition is shown and reveals that most gas was produced in the brewers glucose experiment, at 115.6 cm3 and the condition that produced the lowest average was brewers starch, at 9.4. The range of the averages was 94.3, showing there was a large difference between the values. Analysis of the results: The graph above clearly shows the difference between the three carbohydrate substrates to be significant. It is clear that the order for most CO2 produced is glucose, sucrose, starch, the greatest difference being between sucrose and starch. It also appears that the results are closer together for bakers yeast than for brewers. The average for bakers yeast was slightly higher at 74cm3 than the Brewers at 71.2cm3. Students T test: The descriptive statistics above, however, only tell us what has been found, they do not tell us the probability of achieving the scores we did, and therefore an inferential students t test was applied. The students t test was devised to analyse smaller sets of samples; to determine whether the results were due to chance or the manipulation of the independent variable. It works out that if the difference between the variance of the sum of the two means (of the two samples) is greater than twice the standard deviation of the difference between the means (of the two samples) then this is unlikely to have of occurred by chance, and therefore our data is significant. Glucose v Sucrose bakers: t-Test: Two-Sample Assuming Equal Variances Variable 1 Variable 2 Mean 103.6667 93.25641 Variance 927.0702 595.5641 Observations 39 39 Pooled Variance 761.3171 Hypothesized Mean Difference 0 df 76 t Stat 1.66608 P(T