Factors affecting the activity of enzymes Essay Example for Free

Factors affecting the activity of enzymes Essay Factors affecting the activity of enzymes Aim: to investigate the factors affecting the activity of enzymes. Factors: The factors that could possibly affect the activity of enzymes are: Temperature: rate of reaction increases as temperature increases. Concentration of enzyme: rate of reaction increases as concentration of enzyme increases. pH: extremes of pH denature enzymes. Surface area: rate of reaction increases as surface area increases. Inhibitors: if there are any impurities, then they will restrict the rate of the reaction. Key Factor: I will be using temperature as a variable, and keeping all other factors constant. Therefore, testing temperature as the key factor. Prediction: I believe, that as the temperature of the starch and amylase increases, as will the rate of the reaction. However, once the optimum temperature is reached, the amylase will stop working. Hypothesis: The reason I believe that as the temperature of the starch and amylase increases, as will the rate of the reaction, is because of the collision theory. The collision theory tells us, that the more the solution is heated, the more the particles inside vibrate. Therefore, if the different particles are vibrating a lot more, it means that they will collide a lot more, and so the reaction will occur a lot faster. So in the case of the experiment we will be doing; the higher the temperature of the starch and amylase, the more these particles will vibrate and collide, and so the faster the amylase will be broken down. I also believe, that once an optimum temperature is reached, the amylase will stop working. This is because, above a certain temperature, enzymes, being proteins are denatured (change shape), and so can no longer combine with the substances. Fair Test: In order to make this a fair test, the following things must be taken into account: Ensure that the volumes of amylase and starch are constant. Ensure that the pH levels of the starch and amylase are the same. Ensure that all the apparatus are totally clean, i. e. have no impurities. Ensure that the temperature of the solutions remain the same as planned. Ensure that the temperatures of the water baths and ice bath are kept as constant as possible. Ensure that the starch and amylase solution is kept in the water bath in between each 30-second gap, so as to ensure a constant temperature throughout. Method: Two test-tubes, one filled with 5mg of starch suspension, and one filled with 5mg of amylase solution, are both put into a tub of ice. Whilst these are left inside the tub to cool down, droplets of iodine solution are put in each cavity of the spotting tray. Once the temperatures of the starch and amylase solution have become constant, then they are mixed together, and a droplet of this solution is then added to the first cavity of iodine. The test-tube is then put back in the ice tub, and then every 30 seconds, another droplet of the solution is added to a different cavity of iodine, until the purple colour that should appear, has disappeared. The time taken for the purple colour to disappear, is then recorded. When the purple colour disappears, it means that the amylase has totally broken down the starch. The same process is then repeated, but in water baths, with temperatures of 30? C, 50? C, and one is also done in room temperature. Everything is then repeated once more, and the average times for each temperature are calculated. Diagram: Apparatus: The following apparatus will be used in the experiment: 3 water baths tub pipette 2 syringes 2 beakers 2 test-tubes spotting tray thermometer test-tube holder Results: Temperature (i C) 0i C 20i C 30i C 50i C Time Attempt 1 450secs 270secs 180secs 210secs taken for Attempt 2 480secs 300secs 180secs 210secs starch to Average 465secs 285secs 180secs 210secs disappear 1/T 1/465secs 1/285secs 1/180secs 1/210secs Graph: Conclusion: To a certain extent my hypothesis was correct, but there still were some unforeseen results. For example, I mentioned in my hypothesis that as the temperature of the starch and amylase increases, as will the rate of the reaction. As the graph shows, the rate of reaction did increase as the temperature increased, but only to a point; after 30? C, the rate of reaction began to decrease. However, in my hypothesis, I mentioned that once a high enough temperature is reached, the amylase would stop working. This of course was incorrect, because once it reached 30? C, the amylase did not stop working, it just became less efficient. One thing I noticed whilst looking at the results table, was that as the temperature increased by 10? C, the rate of reaction doubled. This would explain why the graph increases steadily at the beginning, and then starts to steeply increase. Errors and Improvements: Some of the results may have been inaccurate, due to the 30-second range in between each time another droplet is added to a cavity of iodine. This could have been improved upon, by making it only a 5-second range for example, because the exact time when the starch disappears would be closer to the time recorded than with a 30-second range. An example as to why a couple of the results may not have been proportional, is when the starch and amylase were put in the ice tub. It is very unlikely that the solutions would have reached 0? C and remained constant. This could have been improved upon, by putting the solutions in a freezer instead, because it would keep to the same temperature throughout. Show preview only The above preview is unformatted text This student written piece of work is one of many that can be found in our GCSE Patterns of Behaviour section.

growaw Kate Chopins The Awakening - Edna Pontellier’s Awakening :: Chopin Awakening Essays

Edna's Awakening in Kate Chopin's The Awakening      Ã‚  Ã‚   The society of Grand Isle places many expectations on its women to belong to men and be subordinate to their children. Edna Pontellier's society, therefore, abounds with "mother-women," who "idolized their children, worshipped their husbands, and esteemed it to a holy privilege to efface themselves as individuals".   The characters of Adele Ratignolle and Mademoiselle Reisz represent what society views as the suitable and unsuitable woman figures. Mademoiselle Ratignolle as the ideal Grand Isle woman, a home-loving mother and a good wife, and Mademoiselle Reisz as the old, unmarried, childless, musician who devoted her life to music, rather than a man.   Edna oscillates between the two identities until she awakens to the fact that she needs to be an individual, but encounters the resistance of society's standards to her desire.      Ã‚  Ã‚   Kate Chopin carefully, though subtly, establishes that Edna does not neglect her children, but only her mother-woman image.   Chopin portrays this idea by telling the reader "...Mrs. Pontellier was not a mother-woman.   The mother-woman seemed to prevail that summer at Grand Isle".   Edna tries on one occasion to explain to Adele how she feels about her children and how she feels about herself, which greatly differs from the mother-woman image.   She says:   "I would give up the unessential; I would give my money; I would give my life for my children; but I wouldn't give myself.   I can't make it more clear; it's only something I am beginning to comprehend, which is revealing itself to me."   This specifically contrasts the mother-woman idea of self-sacrificing for your husband and children.   Also, the "something . . . which is revealing itself" does not become completely clear to Edna herself until just before the end, when she does indeed give her life, but not her self for her children's sake. Although Edna loves her children she does not confuse her own life with theirs.      Ã‚  Ã‚   Similarly to Edna's relationship with her children is that with her husband, Leonce.   The Grand Isle society defines the role of   wife as full devotion towards their husband and to self-sacrafice for your husband. Edna never adhered to the societies definition, even at the beginning of the novel.   For example, the other ladies at Grand Isle "all declared that Mr.

Five Forces Analysis In The Pc Industry

Rivalry: (High)There are five biggest PC manufacturers-Hewlett Packard, Dell, Lenovo and Acer and apple. None of them dominates the market. Therefore, the PC industry is not highly concentrated.The PC manufacturers focus on the reduction of cost rather than differentiations of the products. By 2011 PC manufacturers’ net profit margin was 5%(excluding apple). The low profit margin causes the intense competition among the PC manufacturers.The growth of the PC industry grows slowly, because the appearance of the tablets. This limitation of growth will lead to intense competition as well.Barrier to Entry (moderate):The Economies of scale is large. The fix cost spending on R&D, selling and marketing is high. Therefore, increasing the production of PCs will reduce per unit cost of the products. Furthermore, large economies of scale require intensive capital investmentThe PC industry has already entered the stage of maturity, meanwhile, the production differentiation is low and custo mers are more sensitive to the price. However, without minimum effective economies of scale, it is hard to lower cost. Thus, the price will be higher than its competitors.The big PC manufacturers have established strong relationship with it distributors, which make it difficult to access to the distribution channels.Buyer Power (weak to moderate):Home consumers represented the biggest segment of PC industries. They are sensitive to the price, but not highly concentrated.Suppliers Power (Moderate):There are two major suppliers of hardware in PC industry. One is Intel and the other is AMD. Though they are highly concentrated industry, but they compete with each other for the market share. The buyers always choose the cheap ones to lower their cost, which limits the power of suppliers.Microsoft is the dominant supplier of software and its OS, therefore, they will exert some pressure to their buyers.Substitute (High):Smart phones and tablets are the substitute of the PC. They erode the market share of the PC. They are increasingly functioning like computer.Another substitution is advanced game devices, like Play station and X-box. Consumers can watch the TV and surf the web and play games online.

Effects of Sleep Deprivation on the Human Metabolome - Free Essay Example

Sample details Pages: 4 Words: 1145 Downloads: 7 Date added: 2019/07/29 Category Health Essay Level High school Topics: Sleep Deprivation Essay Did you like this example? The negative effects of sleep deprivation on brain activity and performance in cognitive tasks have been studied for generations. However, loss of sleep also has a significant impact on the manifestation of various diseases and metabolic disorders (obesity, diabetes) and cardiovascular disease. This is why for this assignment I have picked a paper that focuses on the effect of acute sleep deprivation on metabolomic profiles of patients (Davies et. al. 2014). The study used untargeted and targeted liquid chromatography (LC)/MS metabolomics to examine the effect of acute sleep deprivation on plasma metabolite rhythms. Characterization of plasma metabolites has revealed that lipid and acylcarnitine levels were significantly increased during acute sleep deprivation. Overall, 27 metabolites (tryptophan, serotonin, taurine, 8 acylcarnitines, 13 glycerophospholipids, and 3 sphingolipids) were increased after 24 hours of wakefulness. The levels of all metabolites changed during the 24 h wake/sleep cycle and clear daily rhythms were observed in most cases. Moreover, these rhythms were less apparent after 24 hours of wakefulness, which speaks to the significance of sleep for metabolic processes. Don’t waste time! Our writers will create an original "Effects of Sleep Deprivation on the Human Metabolome" essay for you Create order The significance of this study is enhanced by the fact that this is the first study focused on characterization of the 24 h rhythms of metabolic processes during the wake/sleep cycle and the changes occuring during the wakefulness period. There have been previous studies which used transcriptomic data to show that rhythmic gene expression may be affected by sleep deprivation or sleep restriction. However, metabolic profiling studies are best used for the purpose of characterising changes in specific molecular phenotypes associated with sleep deprivation (rather than inferring the changes in the metabolome from the transcriptome). Participants For the purpose of this study, twelve healthy young males were selected and monitored in carefully controlled laboratory conditions. The controlled variables included environmental light, sleep, meals, and posture during a 24-h wake/sleep cycle, followed by 24 h of wakefulness. Method The present study uses liquid chromatography-mass spectrometry (LC-MS) to ascertain the concentrations of plasma metabolites and link the changes in these concentration to the wake/sleep cycle rhythms. As suggested in the name, LC-MS combines the physical separation of molecules using liquid chromatography with the mass analysis capabilities of mass spectrometry (MS). The coupling of the two technologies provides higher accuracy in identification of structural identity of the individual components with high molecular specificity and detection sensitivity. In the first step (liquid chromatography) solubilized compounds are passed through a column packed with a stationary phase. The needed molecules in the mobile phase (which have the affinity for the stationary phase) get stuck on the solid stationary phase, while other molecules pass through the column freely. This effectively separates out the needed compounds based on their weight and affinity. LC is usually used the separate large non-volatile molecules such as proteins. However, the accuracy of this separation is not high enough for some purposes (for example for identifying isomers). This is where the next step, mass spectrometry, comes in. The sample passes into the vacuum chamber of the mass spectrometer. In simple terms, a mass spectrum measures the masses of molecules within a sample. Mass spectrometry allows to provide structural identity the the individual components of the product that has already been filtered using LC. There is also a modification of LC, which is called HPLC (high performance liquid chromatography). The idea behind this method is using a higher pressure ranging from 50-350 bar to separate out the molecules. Findings An unexpected result of this study is that in comparison with the number of ions and metabolites showing time-of-day rhythms (basically significant changes in expression of these metabolites during the day), fewer ions/metabolites were significantly changed when comparing the normal wake/sleep cycle to the 24 h during sleep deprivation (only 27 metabolites out of 171 were significantly different between the sleep and sleep-deprivation periods). All of these metabolites were increased during the sleep deprivation phase of the experiment, so it is possible that sleep has an inhibitory effect on synthesis of these metabolites. One of the metabolites which has shown increased levels after a 24 h wakefulness period is serotonin. This is an important finding because serotonin is known to be involved in both sleep cycle regulation and depression. Low levels of serotonin and reduced serotonergic neurotransmission are strongly associated with major depressive disorder, so if sleep deprivation over a short period of time (24 h) has shown to increase serotonin levels, this might provide a new avenue of clinical research. The amino acid tryptophan, which is vital for the formation of serotonin and melatonin, has shown significantly increased levels during acute sleep deprivation. This is in line with previous studies, which have indicated that tryptophan is an effective cure for major depressive disorder. It may be possible that the antidepressive effect of acute sleep deprivation is linked to the increased circulating levels of tryptophan, serotonin, taurine, and melatonin, and this subject deserves further investigation. Limitations The protocol described in the study allows identification of only metabolites that show increase or decrease in levels after a short period of time (less than 24 h) and do not show the changes in levels which occur over longer periods of sleep deprivation (longer than 24 h) or during repeated sleep deprivation (chronic partial sleep deprivation). Future applications Sleep deprivation has been previously shown to have an antidepressant effect. In line with this, the authors observed increased levels if serotonin, tryptophan and taurine after 24 hours of wakefulness. Therefore, the results of this study may have potential application in diagnostics and treatment of major depressive disorder, and perhaps even a series of related conditions, such as depressive disorders (seasonal affective disorder, bipolar disorder, psychotic depression, postpartum depression). In general, the metabolomics approach presented in the paper is a step toward understanding the metabolic pathways involved in regulation of the sleep/wake cycle. Determination of the impact of factors such as sleep on the metabolome could lead to future metabolic profiling-based studies aimed at identification of biomarkers of disease and drug effects. Conclusion The study has presented a n implementation of a method for identification of plasma metabolites that were significantly altered during acute sleep deprivation. It has been shown that 27 metabolites (mainly lipids and acylcarnitines, serotonin, tryptophan, and taurine) were increased during sleep deprivation. This study has provided me with some insight into why I might be able to not sleep for short periods of time, such as a 24h period investigated in the study. I myself do not know anyone who tried treatment of major depressive disorder using sleep deprivation, and the fact the people I do know that have it have told me that during the acute phase of MDD they tend to fall asleep for long periods of time and in generally sleep no less than 12 hours. It may be possible that this is in fact directly link to the cause for their disorder, and it is possible that the method suggested in this paper would help them.