Bio Lab Report

Ye Tao BISC220-13155 The Effect of Temperature on the Digestion of Starch by Activity of Enzyme ? -Amylase: Observation of Rate of Starch Disappearance through Iodine Test Introduction An enzyme is a type of protein that, through its own structure including hydrogen bonds, acts like a biological catalyst and is able to accelerate the biochemical reaction rate by lowering the activation energy of the whole process, without which cells could hardly practice any physiological functions within human bodies (Sizer, 1943).Found in the saliva and pancreatic secretions of animals including human beings as well as the plant seeds, bacteria and fungi (Siddiqui et al. , 2010), the enzyme ? -amylase that was studied during the experiment has significant impact on the hydrolysis of starch. By breaking the alpha, 1-4 glycosidic linkages in the carbohydrates, amylase hydrolyzes the starch, a polysaccharides that is stored in plants and cannot be directly digested by animal cells, into maltose, a di saccharide that later generate two units of glucose to undergo metabolisms and provides necessary energy (Slaughter et al. , 2001). The enzymatic activity of ? amylase is facilitated by calcium and chloride ions during the hydrolysis (Marini, 2006 and Siddiqui et al. , 2010). The complete digestion of starch and formation of maltose and glucose can be examined through the iodine test when I2KI reagent is added into the solution and remains brown instead of turning into dark blue, marking that all the molecules of starch have been fully hydrolyzed (Hanes, 1932). While amylase effectively activates the hydrolysis of starch, the efficiency of the catalytic process is influenced by several factors including temperature, pH level and the concentration of the substrates etc.In this experiment, as the ? -amylase is a type of protein, the efficiency of enzyme is highly related to its hydrogen bonds which are affected by the temperature. Though the enzyme is collected from the porcine pancre as, due to its structural similarities to amylase in human bodies, the behaviors of two amylases should resemble each other. Given that under extreme temperature enzymes will be denatured and unable to function and the constant temperature of pigs is around 39 °C, the hypothesis of this experiment is that at 37 °C amylase will catalyze the hydrolysis with the highest speed, followed by amylase at 22 °C.Amylase at 0 °C will react extremely slowly due to the crystallization of hydrogen bonds and at100 °C, amylase will lose its function since it will be denatured. Materials and Methods Four test tubes were marked from A1 to A4. Then, 2mL of 1% starch solution from Carolina Biological Supply Company, 4mL of deionized water and 1mL of 6. 8 hydrion buffer from VWR International/ Micro Essential Laboratories were added into each tube. Another four test tubes were also labeled from B1 to B4 and added 1mL of 1% ? -amylase from porcine pancreas from Sigma Aldrich. Eight tubes were p aired according to the same number (A1and B1 etc. and assigned to environments at different temperature: Tube A1 and B1 were placed into a water bath at 100 °C; Tube A2 and B2 were placed into a water bath at 37 °C; Tube A3 and B3were placed on the tube rack (at about 22 °C); Tube A4 and B4 were placed into an ice bath at 0 °C. All test tubes were kept at different temperatures for 10 minutes. Meanwhile, a control group of starch solution was prepared without amylase. (Bio Lab Manual, 2013) At the same time, a test plate was added 2 drops of I2KI reagent (1% Iodine and 2% KI) from Carolina Biological Supply Company per well.After 10 minutes, when test tubes were still in the original environments, solutions in Tube A1 with B1 were mixed and a timer was started. At each 30-second-inteval, a drop of the mixture was released into the well on the test plate until the solution in the plate did not change into dark blue and remained brown, indicating the end of the reaction by sho wing no presence of starch and presence of maltose and glucose. The experiment was repeated on the tubes at other temperatures. Slow reactions were observed and recorded up to 420 seconds due to time limit.Data were pooled from each bench and average and standard deviation were calculated. The data of the control group were also obtained. Results Figure 1 The test plate of iodine test under different temperature. Dark blue wells indicated the presence of starch while the brown ones indicate the completion of starch hydrolysis. (Upper half: 37 °C; Bottom Half: 0 °C) The rate of reaction was fastest at 37 °C (n=4, mean=212. 5s, SD=66. 1s) while the rate of reaction at 22 °C was only slightly less than it (n=4, mean=217. 5s, SD=61. 8s).Though the previous two groups underwent starch hydrolysis relatively fast, the tubes at 100 °C and 0 °C reacted so slowly that it took more than 420 seconds for their completions (time was only recorded before 420s). There was no hydrolysis in the control group. The time of the reaction completions as the function of different temperatures was shown in the table and graph below. The Effects of Temperature| Temperature (? )| Time of Starch Disappearance(s)| | Bench 1| Bench 2| Bench 3| Bench 4| Mean| SD| Control| >420| >420| >420| >420| 420| 0| 0| >420| >420| >420| >420| 420| 0| 2| 210| 210| 300| 150 | 217. 5| 61. 84658| 37| 270| 180| 265| 135 | 212. 5| 66. 14378| 100| >420| >420| >420| >420| 420| 0| Table 1. Time of Starch Disappearance with Porcine Pancreatic ? -Amylase at Different Temperatures (Time was recorded up to 420s). Graph 1. Time of 1% Starch Disappearance with Porcine Pancreatic ? -Amylase as the Function of Different Temperature Discussion and Conclusion As the data obtained from the experiment, all parts of the original hypothesis were confirmed by the result. Temperature plays an important role during the activation of ? amylase that only during certain temperature range can the enzyme function properly to catalyze biochemical reactions. On one hand, at 37 °C the amylase showed the greatest efficiency in catalyze the hydrolysis of starch. At the same time, the amylase also showed considerable catalytic efficiency at 22 °C. But on the other hand, when temperature dropped or rose to extreme value such as 0 °C or 100 °C, the function of amylase was inhibited and such biochemical transformation of substances could hardly process. This result obtained is consistent with the reality that during normal body temperature, regardless of pig or human beings, mylase is able to catalyze the hydrolysis of starch with the highest speed. Therefore, we may conclude that even taken out from where it was found, the amylase still maintain its original biochemical properties. The experiment did not show the biochemical mechanism of the modification from temperature to amylase activity. However, according to the scientific research done by other scientists, a temperature that ranges from 20-50à ‚ °C could make structures including weak interactions, hydrogen bonds and disulfide bridge exist within and stabilize the enzyme molecules to maximize their activities.At the water freezing point (0 °C), the hydrogen bonds are crystallized and become more constrained and less flexible while at high temperature like 100 °C, the bonds consume certain energy to become unstable and fragile, neither of which contribute to the proper functions of amylase (D’Amico et al. , 2003). While the result of the experiment perfectly matched what was expected, however, such conclusion could only be made at qualitative phase and it is obvious that weakness of this experiment existed and prevented the further understanding of amylase at quantitative level.Several modifications to the current experimental designs could be made to enhance its accuracy. Firstly, the sample size needs to be expanded. With only four groups, the data was so limited. As a result, the data had great standard devia tions of more than 60 seconds. Simultaneously, the random errors were at high possibility to take place. Therefore, with the increase of sample size, the data can be more accurate and stabilized and potential random errors could be discarded to ensure the coherence of the data.Furthermore, even though neither the test tube at 0 °C and 100 °C enabled the completions of starch hydrolysis, the reasons of the two groups are not the same. Therefore, in order to detect the reason of the loss of catalytic ability, follow-up experiments need to be practiced. A possible design might be to change the test tubes from 0 °C or 100 °C into 37 °C for another 10 minutes then redo the iodine test to see this time whether the amylase can function well or not.This manipulation will convince the hypothesis about the reason behind the superficial phenomena that was shown in the original experiments and present the difference between denaturing of protein and crystallization of hydrogen bonds. It is important for people to thoroughly understand the amylase activity and all the factors that are potentially capable of influencing such activity through which people can understand how human bodies work as well as the physiology of other organisms. At the same time, the research in amylase activity could potentially bring economical benefits to industrialized starch products manufacturing.And finally, the amylase activity has shown its significance in medical clinical trial that diseases including hyperamylasemia  or hyperamylasuria are proven to be related to the amylase in the human serum and urines (Salt 2nd, 1976). References General Biology BISC 220 Laboratory Manual. (2013). University of Southern California. Lab2, pp33-36. D'Amico, S. , Gerday, C. , ; Feller, G. (2003). Temperature adaptation of proteins: engineering mesophilic-like activity and stability in a cold-adapted ? -amylase. Journal of molecular biology,  332(5), 981-988. Hanes, C.S. (1932). Studies on pla nt amylases: The effect of starch concentration upon the velocity of hydrolysis by the amylase of germinated barley. Biochemical Journal,  26(5), 1406. Marini, I. (2005). Discovering an accessible enzyme: Salivary amylase: Prima digestio fit in ore: A didactic approach for high school students. Biochemistry and Molecular Biology Education,  33(2), 112-116. Salt 2nd, W. B. , ; Schenker, S. T. E. V. E. N. (1976). Amylase–its clinical significance: a review of the literature. Medicine,  55(4), 269. Siddiqui, Z. S. , & Khan, M. A. 2011). The role of enzyme amylase in two germinating seed morphs of Halopyrum mucronatum (L. ) Stapf. in saline and non-saline environment. Acta Physiologiae Plantarum,  33(4), 1185-1197. Sizer, I. W. (2006). Effects of temperature on enzyme kinetics. Advances in Enzymology and Related Areas of Molecular Biology, Volume 3, 35-62. Slaughter, S. L. , Ellis, P. R. , & Butterworth, P. J. (2001). An investigation of the action of porcine pancreatic ? -amylase on native and gelatinised starches. Biochimica et Biophysica Acta (BBA)-General Subjects,  1525(1), 29-36. Bio Lab Report Biology lab report Estimating glucose concentration in solution Done by : Hasan Al-jowder 11E KC Introduction: The purple pink solution of potassium permanganate (MnO4 -) is reduced by glucose to a colourless solution of manganese ions (Mn2+). MnO4- + 8H+ + 5e- Mn2+ + 4H2O The time taken for the loss of colour from a standardised solution of permanganate is directly related to the concentration of glucose present in solution. Research question:How does the different concentration of glucose solution which have the same volume affects the time taken for the pink color of the potassium permanganate to turn into colorless? Hypothesis: The higher the concentration of glucose, the shorter time taken for the reduction of potassium permanganate, hence resulting in shorter time taken for the pink color of potassium permanganate to decolorize. This is because the concentration of glucose molecules in glucose solution is high thus more electron are donated to the permanganate within a constant period.Variables: †¢Independent: The concentration of the glucose solution †¢Dependent: The time taken for the pink color of the potassium permanganate to turn into colorless †¢Controlled: Volume/Units Materials list : †¢Eye protection †¢A timer †¢a glass rod †¢a boiling tube and a rack †¢3 beakers †¢3 syringes †¢6 labels †¢glucose solutions (2%,4%,6%,8%,10%,12%) †¢3 solution of unknown glucose concentration (A,B,C) †¢sulphuric acid †¢potassium permanganate Procedure: 1. label your three beakers sulphuric acid PP- for potassium permanganate G- for glucose 2. abel your syringes in the same way. 3. add about 25 cm3 of sulphuric acid and potassium permanganate to the beakers – this will be your stock to use throughout the experiment. note which glucose solution you are testing first. 4. use the correct syringe to place 10 cm3 of the first glucose solution into the boiling tube. 5. add 5 cm3 of sulphuric acid. 6. add 2 cm3 of potassium permanganate and start the clock. 7. stir with a stirring rod and stop the clock as soon as the pink color disappears. 8. record the time and the glucose solution used. . rinse the syringe you used for the glucose solution. 10. repeat using the other glucose solution. 11. repeat for a solution of unknown concentration (A B or C) 12. record your own results and if possible class average results in a table. Table: Glucose concentrationsTime taken to change color 2%1 minute 41 seconds 4%1 minute 13 seconds 6%45 seconds 8%41 seconds 10%35 seconds 12%32 seconds Unknown A48 seconds Unknown B1 minute 13 seconds Unknown C2 minute 56 seconds Graph : conclusion: Evaluation: sources of error= the temperature of the water was not the same with all the concentrations †¢minor inaccuracy in watching the exact time that the color changes absolutely †¢inaccuracy in using the stop watch Reference: https://www. google. com. bh/#hl=en&sclient=psy-ab&q=estimating+glu cose+concentration+in+solution+lab+report+hypothesis&oq=estimating+glucose+concentration+in+solution+lab+report+hypothesis&gs_l=hp. 3†¦ 3351. 18905. 1. 19921. 11. 11. 0. 0. 0. 0. 421. 2839. 2-10j0j1. 11. 0†¦ 0. 0†¦ 1c. 1. 7. psy-ab. csPQdc8wzZA&pbx=1&bav=on. 2,or. r_cp. r_qf. &bvm=bv. 44011176,d. d2k&fp=34c3fbe89c60be0d&biw=1366&bih=629

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Pay Equity In Labor Force Movement Essay Debates about women’s rights at work and the gendered dimensions of employment inequality were notable and contested features of Canadian political discourse throughout the second half of the twentieth century. Concern about these issues took root during the 1940s, when women experienced dramatic shifts in their employment opportunities as a result of being drawn into and later jettisoned from the reserve army of wartime labor. Pressure to improve women’s employment conditions, particularly in the burgeoning public sector, recurred in the mid-1950s. However, it was in the 1960s, once the second wave of feminism took root in Canada, that women began to develop a sustained critique of the employment inequalities they experienced and pressure their governments to address the problem through policy innovation and change. 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In particular, feminists thought that women’s maternal work had to be recognized in discussions about promoting gender equality in the workplace. As Westhues, a well-known socialist feminist, once argued, â€Å"As long as women have the primary responsibility for maintenance of the home and for child care, we will be less than able to pursue job opportunities and our domestic commitments will be used to justify discriminatory employment practices. † (Westhues, 45-58) Growing awareness of the need to link questions about production and reproduction in analyses of women’s economic position was by no means unique to Canadian feminism. It was, for example, well established in the early writing of second-wave feminists in Britain and the United States. 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After all, only one-tenth of the Canadian labor force is regulated by the federal government, and even at the start of second-wave feminism both federal and provincial governments had been involved in employment opportunity and child care initiatives. Moreover, even though the federal government has the constitutional capacity to use its spending power to underwrite the provision of state-subsidized child care, it is the provinces that retain constitutional control over the delivery of this service. The federal focus of women’s campaigns was encouraged by the fact that the renaissance of Canadian feminism occurred within the context of a broader social project to achieve universal welfare guarantees, assured by the Canadian state. It was reinforced by the government of Canada’s decision to establish the 1967 Royal Commission on the Status of Women (RCSW) to inquire how best the federal government could ensure that women enjoyed â€Å"equal opportunities with men in all aspects of Canadian society. † It has since been sustained by the work of activists in national organizations, in particular the National Action Committee on the Status of Women (NAC), founded in 1972, and the Canadian Day Care Advocacy Association (CDCAA), established in 1982 and renamed the Child Care Advocacy Association of Canada (CCAAC) in 1992. However, despite a long history of feminist engagement with the federal state, women’s repeated campaigns for the development of policies to address the double-edged nature of gender inequality in employment, and the clear recognition of these demands in reports of royal commissions and task forces, the federal policy response has been uneven. Policies to eradicate sex discrimination at work and promote women’s employment opportunities have been developed and implemented in the federal policy sphere. By contrast, the federal government has not developed policies to promote a publicly funded system of child care in order to enhance women’s employment opportunities, save as emergency measures during the Second World War or as an element of broader initiatives to get â€Å"welfare mothers† out to work. Instead it has treated child care as a fiscal issue for which parents can receive subsidies through federal taxation. This paper examines why a double-edged interpretation of women’s employment inequality, which recognizes the public and domestic dimensions of women’s work, has not been fully absorbed into federal policies to promote gender equality in the sphere of employment. The analysis follows the development of debates about women’s rights at work from the period of reconstruction after the Second World War, when questions about eradicating employment discrimination against worker-citizens first emerged in Canadian political debate, through to the close of the twentieth century. It examines federal policy developments under Liberal and Conservative governments, showing that even though the reports of federal royal commissions and task forces encoded feminist demands for a double-edged attack on employment inequality, questions about promoting women’s employment equality and child care were continually driven apart in the federal policy process. Women’s Paid and Caring Work  While this is by no means the first time that scholars have considered the relationship between Canadian women’s work inside and outside the home, it is noticeable how the link between these two aspects of women’s labor was explored by historians and sociologists before being addressed by analysts of public policy. In the late 1970s, members of the Women’s History Collective at the Ontario Institute for Studies in Education and the Clio Collective in Montreal pioneered research in Canada on how women’s labor had shifted from the unpaid domestic sphere into the world of paid employment. In the process, they unearthed textual and oral histories that demonstrated how, despite this transition, women still faced the double bind of a double-day in which they went out to work for pay and home to work for love. Their findings were reinforced in late 1970s and 1980s by sociological analyses of women’s work arguing that because women so often entered employment while maintaining primary responsibility for the care of their children, they frequently found themselves concentrated in low-paid, low-status employment. Despite the fact that historians, sociologists, and feminist activists drew attention to the â€Å"double ghetto† of women’s working lives, discussions about policies to promote women’s employment opportunities and improve the provision of child care evolved as distinct scholarly debates. The literature on policies to promote Canadian women’s employment opportunities emerged within the context of broader discussions and debates about the development of policies to root out discrimination in the workplace. By contrast, the literature on Canadian child care policy evolved around questions about the development, cost, and politics of implementing public policies to promote the welfare, education, care, and development of young children. In recent years, however, policy analysts have paid much greater attention to the link between women’s paid and caring work. Jacobs, 120-128) Nonetheless, no one has yet considered why Canadian government policies to promote women’s employment opportunities and improve the provision of child care have been developed at such different rates and, despite repeated calls to the contrary, not linked in the design of public policies to promote gender equality in federally regulated employment. This pattern of inquiry is understandable, given the discrete historical development of policies concerned with child care and those concerned with women’s employment. However, it unduly limits our understanding of the gendered dimensions of employment inequality in Canada and fails to capture the empirical reality of many women’s working lives. Double-Edged Nature of Women’s Employment Inequality Why did women’s double-edged demand for equal employment opportunities and child care emerge in Canada in the 1960s and 1970s? After all, from the mid-1950s Canada experienced one of the fastest rates of labor force feminization in the Western industrialized world. The decline of manufacturing industries and the concomitant growth of the tertiary sector in the 1950s and 1960s meant that while industries that had traditionally attracted men closed down, those demanding support skills that had long characterized women’s traditional domestic roles expanded. Moreover, in countries like Canada, where welfare states were being established, the growth in women’s employment intensified most quickly. The much trumpeted rise in female labor force participation rates did not, however, mean that women engaged in paid employment on the same terms as men. The occupational segregation of Canadian men and women persisted in both horizontal and vertical forms. In fact, this process intensified with the increased participation of women in the paid labor force. As a result, the vast majority of women found themselves working in poorly paid occupations, situated in the lower echelons of private companies and public sector organizations. Moreover, as Jacobs have noted, although the creation of welfare states meant that â€Å"women as a group had more employment opportunities open up for them than men† in the mid-twentieth century, the growth in women’s employment was in the part-time sector of the labor force, which was increasingly dominated by women in all OECD (Organization for Economic Co-operation and Development) countries. Jacobs, 120-128) This simply intensified the inequalities of employment opportunity that women experienced because part-time work is concentrated in the least-skilled, lowest-paid, and most poorly organized sections of the labor force, where benefits are usually more limited than in the full-time sector. The rapid growth in women’s participation in part-time rather than fulltime employment reflects two other factors about the feminization of the Canadian labor force. On the one hand, it relates to the type of work that the service sector has generated and to the increasing flexibility demanded of its employees. On the other hand, it reflects the fact that the greatest increase in female labor force participation rates since the 1960s has been among women with young children. In the early 1960s, most female employees in Canada would leave the workforce when their first child was born and return only when their youngest child had entered school. By the mid-1980s most women with young children went out to work. Indeed, as Pendakur have noted, â€Å"By 1991 all traces of the reproduction function had disappeared with female labor force participation rates peaking in the major family-rearing age categories†. The double burden that women experience from juggling their employment while continuing to care for their children has been reinforced by the limited provision of subsidized child care spaces in Canada. In the late 1960s, when women began to pressure the federal government to address the minimal provision of child care for working women, federal subsidies for child care were limited to support for welfare mothers under the 1966 Canada Assistance Plan. This pattern changed very little in the course of the twentieth century, although federal subsidies to support child care for low-income families became increasingly tied to efforts to get mothers receiving welfare out to work. Although recent federal publications on the status of day care in Canada boast â€Å"a twenty-five-fold increase† in child care spaces since the government first gathered these data in 1971, in fact the proportion of children of working mothers who have access to regulated child care remains very low. As a result, most working parents remain highly dependent on informal, unregulated child care. Indeed, as Brockman noted, in the mid-1990s â€Å"children in informal child care arrangements accounted for eighty per cent of all child care used by parents in Canada. † (Brockman, 78-93) The federal state in Canada has addressed questions about promoting equal employment opportunities for men and women in the public sphere with relative ease but has failed to recognize that this project cannot be achieved without addressing the questions of child care that affect so many women’s working lives. While the reasons for this are complex, some insights from feminist theory may help us to begin this exploration. In recent years, a number of feminist theorists have discussed how the concept of worker-citizenship that took root as welfare states were developed in countries such as Canada did not take account of the different contexts in which women and men often assumed employment. (Pendakur, 111-120) As a result, when questions about promoting equal employment opportunities for men and women began to emerge in the 1950s and ’60s, they were framed in terms of women achieving the same opportunities as men. Indeed, Canadian have tried to develop a more nuanced concept of worker citizenship that not only respects the objective of equality of opportunity but also takes workers’ particular circumstances into account and, in the case of women, enables them to integrate their paid and caring work better. In the process, women have argued that a state that upholds the principle of gender equality must develop policies that take account of the interconnectedness of the public and domestic spheres and recognize the different contexts in which men and women often assume employment. Conclusion Nonetheless, although Canadian feminists have a long history of active engagement with the state, developed through a â€Å"visible and articulate women’s movement† that has successfully placed issues on the political agenda, the result, more often than not, has been that their demands have been contained within a limited set of reforms. As a result, those aspects of gender discrimination in the workplace that concern practices within the public sphere have been acknowledged through the introduction of anti-discrimination and employment equity policies. By contrast, women have had more difficulty getting their proposals for policies that transcend the public/ private divide, by linking questions of equal employment opportunity with those of child care, acknowledged in the federal policy arena. Despite their efforts to forge these links through two major royal commissions and other government inquiries, problems of gender inequality in employment are still primarily defined as issues located within the public sphere of employment. Without doubt, over the past thirty years there have been clear improvements in the position of women in the federally regulated section of the Canadian labor force. Nonetheless, women continue to cluster in the lower echelons of companies and organizations and remain under-represented in more senior positions. While this persistent pattern of inequality has many causes, paper shows how it reflects a federal policy process that concentrates on ensuring the comparable treatment of male and female employees once they have entered the labor market, yet, for complex reasons, repeatedly stalls on developing a more expansive approach to child care. As a result, federal policies to promote gender equality in the sphere of employment neglect the inequalities of access and participation that many women experience as they continue or resume employment once they have dependent children.