The charges holding the tertiary structure and the enzyme and substrate together are unaffectedly leading to a higher amount of product being formed. 4 bonds (S-S, ionic bonds) begin to break. For pepsin, which is active in the stomach, the optimum pH is 2 (the pH of the stomach). This shows that the biggest increase was from pH 3 to 4. A water bath was heated to 25°C. As the substrate concentration increases, the Enzyme reaction rate increases. Enzymes can be either activated or inhibited by other molecules. I will measure the distance moved and will take an average for the pH. On the white tile, I will place the potato cylinders. This is known as denaturing and causes a diminishing activity level from the enzyme catalase. Firstly, there were difficulties with handling various apparatus which restricted the reliability of my experiment. QUEENSLAND ACADEMY FOR HEALTH SCIENCES INTERNATIONAL BACCALAUREATE Term 1 2013 SUBJECT: BIOLOGY YEAR 11 HL & SL Name of Student: Name of Teacher: FORMATIVE ASSESSMENT ITEM: Chemistry of Life Practical. Independent Variable The independent variable is the value of the pH buffer (from 1-7) which was used in each beaker of H 2 O 2 . Effect of pH Each enzyme has an optimum pH. If, however, the temperature rises above a certain point, the heat will denature the enzyme, causing it to lose its three-dimensional functional shape by denaturing its hydrogen bonds. Catalase is a common enzyme found in all living organisms. There are five main ways that enzyme activity is controlled in the cell. Also, the changes in the active site would be damaged. This was used to keep the test tubes blocked to stop the oxygen escaping. When there’s more substrate than enzymes (substrate becomes the limiting factor) it will stay at one level. 7mm. Both were stood in a water bath until they reached the correct temperature. Apples and other fruit will turn brown when they are cut and the enzyme contained in the fruit (tyrosinase) and other substances (iron-containing phenols) are exposed to oxygen in the air.. However, the active site of the enzyme is still affected and causes the charges to become damaged leading to denatured enzymes. (2018, Dec 03). Generally, there is. PhDessay is an educational resource where over 1,000,000 free essays are collected. Investigating the Effect of Ph on the Activity of the Enzyme Catalase. Everything in my experiment happened the way it should have happened but there were two anomalous results at pH 5 and pH6. The aim of my investigation is to find out how different pH’s will affect the enzyme activity and how this will affect the rate of reaction. PH Each enzyme has an optimal pH that helps maintain its three-dimensional shape. To investigate the effect of temperature on the activity of trypsin - using casein as the substrate. But, there could have been different concentrations of catalase present in the different discs. The effect of sunlight on hydrogen peroxide might have had a problem on the stability of it as it was left out of the brown bottle that would normally protect the chemical. As the pH became more alkaline the rate of reaction decreased. I will then pour the potato disks and the buffer into the test tube. This means less enzyme-substrate complexes form when pH is acidic, leading to fewer products being formed. For four of the beakers, add 15ml of the selected pH buffer (beaker 1 – pH 4, beaker 2 – pH 6 and so forth all the way to pH 10). Then, by using a pipette, I will pour 10cm? The OH- ions bind with the positive charges in the enzyme and active site. Sketch Graph to show the expected effect of differing pH levels on the activity of the enzyme catalase. This was difficult to do and was not done as soon as the reaction began. Another important pathway is the effect of ST (but potentially also SWC) on enzyme activity itself by affecting enzyme affinity for the substrate (Razavi et al., 2015). This contrasts directly to the amount of time taken by the disc at the optimum pH of 7 – where the average value was the much lower 4.51s. However, this device also contains a couple of limitations. The temperature was kept constant using a water bath, the temperature of this was 25? On the whole, the data that was obtained exhibited a good level of reliability. This was the better device to use rather than the gas syringe as it contained the best way of getting measurements. The catalase is no longer able to function as it is denatured. For this piece of coursework, I will be concentrating on changing just 1 factor (pH) to show that this is the one that can change results. Few factors that affect enzyme activity. E. g. Hand in Glove. V-max is where all the enzymes are occupied in E-S complexes. Oxygen Reduction Reaction of Third Element-Modified Pt/Pd(111): Effect of Atomically Controlled Ir Locations on the Activity and Durability. C (room temperature). As a consequence of this, the hydrogen bonds that determine the 3-D shape of the protein are altered. However, the conditions in the human liver for catalase enzyme activity occur at pH 7, suggesting that due to adaptation over time, the body has determined that a neutral pH provides the very best conditions for catalase to operate under. Further, enzymes and their activity are very sensitive to temperature and pH. This will be my accountable variable. To another test tube, add vinegar to the potato which will lower the pH, making it acidic also having an effect. The fifth set should be left without a pH buffer to act as a control. 5 = 6.33 seconds (± 1s). It moved the red dye 11. of hydrogen peroxide into one of the measuring cylinders. It has now reached an optimum temperature where there’s optimum energy. Changes in pH do not only affect the shape of the catalase enzyme but also change the shape or charge properties of the hydrogen peroxide substrate so that the hydrogen peroxide will not bind to the active site and thus cannot undergo catalysis. Experiment Description Research Overview Using the forceps, immerse a paper disc of regular and consistent shape and size (taken from a collection of hole punch detritus) into the catalase solution. In the simplest case of a monomeric enzyme with a single active site, the K m is independent of the enzyme concentration, in principle. This may result in the hydrogen bonds breaking therefore enzyme structure may change,. Its functions include the conversion of Hydrogen Peroxide, a powerful and potentially harmful oxidizing agent, to water and oxygen. The logistical and financial difficulties of this solution are, of course, noted. Synthesis: How does pH affect the activity of enzymes? 3.01 Effect of pH 3.02 Discussion 3.03 Discussion - answers 3.04 Effect of pH - preparation All zipped. There is a steady increase from pH 3 to pH 6 and it increases, there is more distance that the dye has moved and therefore this shows an increase in the rate of reaction. This occurred as the charges holding the tertiary structure together would have been affected. This may have contributed to results being variable, as due to this flaw in the method it is difficult to standardise the results with the same conditions, A different measurement technique for the production of gas could be used – perhaps a gas syringe if the experiment was conducted in a different way, using different volumes and concentrations of the enzyme and the substrate, Catalase concentration varied wildly due to imprecise source (could have come from all sorts of different Ovis aries whose liver concentration of catalase would fluctuate greatly) – so difficult to be exact, Since the higher the concentration of catalase, the higher the rate of reaction, this variation of the nature of the catalase used in different parts of the lab could have caused a lack of accuracy between the sets of trials at each pH value. I will be using the same concentration and volume of hydrogen peroxide (substrate) because if I change too many variables it will make it difficult to know which affected the results. An increase in energy causes molecules to vibrate. To export a reference to this article please select a referencing stye below: If you are the original writer of this essay and no longer wish to have your work published on UKEssays.com then please: Our academic writing and marking services can help you! The enzyme salivary amylase is most active at pH 6.8. Enzymes are usually very specific as to which reactions they catalyze and the substrates that are involved in these reactions. My dependant variable will be the time it takes for the red dye to move across the monometer. The substrate and enzyme are not complimentary. This was a continuous problem that caused many difficulties. How could this have affected the results and hence the conclusion? This alters the ionic bonds of the enzyme that contribute to its functional shape. Extremely high or low pH values generally result in complete loss of activity for most enzymes. In the future if catalase was taken from the livers of Ovis aries that exhibit similar physical characteristics (size, age, gender etc.) As the pH became more alkaline the rate of reaction decreased. Another problem was bungs. 7mm. There could have been problems also because of my technique. This is an increase of 3. Company Registration No: 4964706. Some enzymes are produced in an inactive form, therefore, need to be switched on by the addition of a non-protein group, this sometimes causes a permanent change. I will have to wear safety goggles to protect my eyes. The curve of best fit shows that there are two anomalous results at pH 5 and pH 6 therefore all the other points are correct. It can be seen from the graph that at pH 5 and pH 6, the dot was not on the curve of best fit proving it to be an anomalous result. The monometer appeared quite simple to use and I thought that it would be easy But it turned out this was the hardest piece of equipment instead and caused me the most problems. Temperature Each enzyme has an optimum temperature at which it works best. VAT Registration No: 842417633. PHSchool.com has been retired. number: 206095338. We put the products in this order because the reaction starts as soon as the hydrogen peroxide goes in and we want the reaction to start just before we put the bung on so none of the oxygen escapes. Regulation. Besides it has revitalized the function of Peroxidase. Enzyme Biocatalysis Andr? The salivary amylase did not react in the tubes that had pH tablets of 5 and 8. After the optimum ph, there is a decreasing gradient showing the more alkaline the solution is, the lower the rate of reaction. At this pH, the temperatures changed from 25 C to 26 C. There was a slightly higher rate of reaction than what it should have been according to the curve of best fit but it still follows the pattern that there is a positive gradient for the acids and a negative gradient for the alkalis. This shows that the more pH varies from the optimum level of pH7, the less active the enzyme catalase becomes in breaking down the hydrogen peroxide, because at low and high pHs less gas is being produced at the same rate to propel the disc upwards. This is the best pH for the enzyme to collide with the substrate and successfully bind. If the properties of the active site change, the substrate can no longer combine (I. e. increase in protons of hydroxyl ions will repel the substrate) pH can also affect individual amino acids as the formation of zwitterions are common. The pH can stop enzyme activity by denaturating (altering) the three-dimensional shape of the enzyme by breaking ionic, and hydrogen bonds. the inhibitory effects of heavy metal ions. Due to Adobe’s decision to stop supporting and updating Flash® in 2020, browsers such as Chrome, Safari, Edge, Internet Explorer and Firefox will discontinue support for Flash-based content. But, then there was only a small steady increase at Ph5 to 5. Also, as the pH decreased to pH 3 and 4 (acid), the rate of reaction was slow. During my investigation, I recognized that there were limitations to both the apparatus and techniques used. It is clear that as pH increases and decreases from pH 7, then the time taken for the paper disk to rise and fall through the hydrogen peroxide solution increases. Obtain five test tubes and put a mark 2 cm from the bottom of each using a wax pencil. It was expected that the mean time taken (s) (± 1s) for pH 4 and pH 10 would be more similar than 8.93s and 6.75s respectively, due to the fact that these two values are the same difference from the optimum pH (of 7). Acidic amino acids contain carboxyl functional groups in their side chains. Hire a subject expert to help you with Investigating the Effect of Ph on the Activity of the Enzyme Catalase. Suggestion for amelioration of this problem, Beaker size not entirely consistent – since they are designed by humans, and due to meniscus effect the volume of substance in the beaker may be deceptive, This created room for error with regards to the measurements – if too much hydrogen peroxide had been used then the effect of the pH changes on the experiment would be less pronounced and would thus lead to less clear results. But as the pH number was increased to pH4, it had increased to 4. Validity and Reliability As I’ve just discussed, various factors affect enzyme activity. Above or below an enzyme’s optimum pH, its activity is lower. The acid in lemon juice inactivates polyphenol oxidase to prevent browning. I think that this conclusion is fairly accurate. The gradient is similar to the positive gradient of Ph 5 and 6. This can result in SWC having a protist-mediated impact on soil enzyme activities. The following graph shows reaction rates of various enzymes in the body. Explain how increasing amount of sucrose in food affects sucrase activity. This leads to less enzyme-substrate complexes, and a lower amount of product being formed. I will then place the hydrogen peroxide and straight away after this, I will place the bung on top of the test tube straight away to stop oxygen from escaping. Above and below this range, the reaction rate reduces as enzymes get denaturated. As the temperature increases, molecular motion increases resulting in more molecular collisions. The results do not entirely represent the perfect trend which was hypothesized at the beginning though. a chemical that blocks the effect of histamine in a susceptible tissues. Then, by using another pipette, I will pour 10cm? This 15ml should be measured carefully using a graduated syringe. Substrate Concentration Rate of reaction will increase proportionally to the sub concentration until V-max. Ensure it is well mixed. Do you have a 2:1 degree or higher? In the results section you were asked if rate of increase of sucrase activity was greater when sucrose concentration went from 2.5 to 7.5 g/l or when it went from 22.5 to 27.5 g/l. I will keep this volume the same for each of my tests to make it fair. PH 7 allows the reaction to take place faster as enzyme-substrate complexes can be formed to produce a product. Hydrogen peroxide, which is a harmful by-product of the process of cellular respiration is broken down if it builds up in concentration in the cells. Then, I will connect the test tube to the monometer by the delivery tube. This would have resulted in some oxygen escaping giving me a slightly lower number of oxygen produced than was actually produced. The earlier segment of a biphasic plot of log C against t (following intravenous injection of a drug) represents the “distributive phase” of a drug’s sojourn in the body. But, there were the two anomalies but this was because of a variable. cia Universidad Cat? Investigating the effect of pH on the activity of the enzyme catalase. This follows the trend observed in most scientific investigations about the effect of pH on enzyme activity – and resembles the hypothesis diagram from the start of this report. Tests can be preformed to determine the effects of different conditions on the enzyme function. Enzyme Model : Index > Animations > Enzyme Model . I am going to show this by doing an experiment with potato disks. It is a weak acid. It moved the red dye 11. However this does not solve the inherent (and perhaps unsolvable) problem of the delay in human reaction times. of pH buffer solution and pour it into the other measuring cylinder. A simple model allowing the user to demonstrate the effect of various factors on an enzyme catalysed reaction. This occurred as it affects the bonds in the active site of catalase. A3. There is a slow decrease after pH 7 and it is a negative correlation. The rate of reaction is slow due to insufficient energy (kinetic), this means there are very few collisions between substrate and enzymes. 3 Effect of pH Timing the disappearance of blue colour at different pH values. can use them for free to gain inspiration and new creative ideas for their writing assignments. 0mm in one minute. The rate of reaction is affected by changes in pH. Also as I am using pH 3 to pH 9 I am going from acid to alkali giving me a wide range of results. Our academic experts are ready and waiting to assist with any writing project you may have. It will bleach clothes. of the enzyme activity. Most enzymes function between a pH of 6 and 8; however pepsin in the stomach works best at a pH of 2 and trypsin at a pH of 8. Enzyme activity may be influenced by environment (e.g., temperature, and pH) and needs to be considered separately:[12]dCSdt=D(CS, in−CS)−rwhere r ((mol-S) h−1) is the rate of enzymatic reaction that may follow any of the common enzyme kinetics expressions, for example, Michaelis–Menten, substrate inhibition, product inhibition, or Hill kinetics [5, 6]. the organism studied in the experiment (if applicable), context for the results: the treatment applied or the relationship displayed, etc. Then at pH6, there was another increase to 8mm which is an increase of 2. mm. Safety Hydrogen peroxide is an irritant and highly corrosive, therefore. This shows that the more acidic it is, the lower the rate of reaction. This is because I used potatoes as the form of my catalase. This is because the problems that have existed have not had a significant effect on my results and my conclusions prove the aim. An increase in temperature would give the particles higher energy and so there would be an increase in collisions. After this point, there is only a slight increase (at pH 6). From pH 8 to 9, there was a steady decrease of 4. More enzyme-substrate complexes are formed. In other words, digestion of food by salivary amylase is also effected by pH and temperature and can be verified experimentally. The tertiary structure is now permanently altered and therefore the active site and substrate are no longer complimentary so no products can now be made. The model isn't really robust enough to generate meaningful data but it does show the general effect of the factors and helps students visualise the reaction. The trend of the data obtained overwhelmingly supports the hypothesis that was made. They are biological catalysts that can speed up a reaction rapidly. Most human enzymes work at an optimum pH of around 7. Cold temperature, on the other hand, slows down enzyme activity by decreasing molecular motion. This means that there is a relationship between the pH and the rate of reaction. All the enzymes have still not been affected at this point and there has not been a permanent change. In a covalent bond, the atoms are bound by shared electrons. 15ml was added each time using a graduated syringe. Then at pH7, the enzyme activity is at its maximum and so is the rate of reaction. or even simply from the same animal this would improve the accuracy of the results since the catalase concentration would be more consistent. Let us examine enzyme kinetics as a function of the concentration of substrate available to the enzyme. How does temperature affect the rate of reaction for Lipase? A lower pH means the substance is more acidic. The majority of these are intracellular enzymes. I will also be measuring the rate at which oxygen is evolved and how it reflects the activity of the enzyme catalase. If the conditions become more alkaline, then due to the proliferation of OH– ions, the charge becomes more negative. 0mm, from 9.3mm to 5. One molecule of catalase can convert millions of molecules of hydrogen peroxide to water and oxygen per second. Keisuke Kusunoki, Daisuke Kudo, Kenta Hayashi, Yoshihiro Chida, Naoto Todoroki*, and ; Toshimasa Wadayama This made my results more accurate. There are relationships between the amount of oxygen produced and the pH used. In conclusion, I can say that as the pH increases, so does the rate of reaction meaning that the enzyme activity increases. I will be using different pH buffers in my experiment; from pH3 to pH9, and will have a range of variables; dependant and independent. This is because my graph showed exactly this because there was a positive gradient for the acids and at pH7 it reached its maximum, and then there was a negative gradient for the alkalis. We use cookies to give you the best experience possible. lica o de. Introduction. Enzymes are generally globular proteins that have primary, secondary, tertiary, and maybe quaternary structures. The effect of substrate concentration on the rate of enzyme activity of Catalase Aim To investigate the effect of substrate concentration (manipulated by increasing concentration of hydrogen peroxide) on the. However, there is one limitation as the investigation was carried out over a period of a couple of days. The standard deviation was calculated to show how much the results varied from the mean on average (the spread). If the disc settles at the side of the beaker or gest caught on the sides, remove it with the forceps and repeat that trial. One of the tubes had to be completely blocked using a clamp so no oxygen could escape; this had to be done a couple of seconds after the catalase was added. Many coenzymes are derived from vitamins. This will help me work out close trends and get me a good range of results. Pepsin is found in the stomach, amylase in the saliva, and phosphatase in the liver. Materials and method. PH 3 moved the red dye 1.mm; PH4 moved it 4. No plagiarism, guaranteed! Covalent Bonds. This is due to the fact that the human eye is not precise in analysing such measurements, Spend some more of the science department budget on mathematically produced beakers which are all precisely the same size. Study for free with our range of university lectures! A higher temperature generally results in an increase in enzyme activity. If the conditions become more acidic, then due to the proliferation of H+ ions, the charge becomes more positive. pH – using buffers to maintain a pH (see also Investigating the effect of pH on amylase) comparing the effects of trypsin with the effects of other enzymes – lipase or amylase – to demonstrate the specificity of enzyme action. However, at very high substrate concentrations, the enzymes become saturated with substrate and a higher concentration of substrate does not increase the reaction rate. The standard deviation was low for all data points, with the maximum being 1.16. But, this wasn’t that unreliable because I think that this happened because of the change in my temperature. *You can also browse our support articles here >. On the whole though, in this investigation pH clearly has had an effect on the ionization of amino acids – the proteins that make up the catalase enzyme. Basic amino acids contain amine functional groups in their side chains. The bung also had to be placed seconds after the catalase was added, this could have also resulted in some oxygen escaping. Although not as many enzymes become denatured leading to a slightly higher number of products being formed (not as great as pH7). The objective of this study was to … The meniscus effect in liquids can be overcome by using a goniometer – which is an instrument that measures contact angles, Sometimes the catalase in the filter paper disk reacted too quickly/not quickly enough with the hydrogen peroxide, since there had been different levels of absorption into the paper. Without the charges present the substrate no longer fits, resulting in the enzyme being denatured. The catalase and hydrogen peroxide bond form water and oxygen successfully. This would have directly affected the results – since time was being measured as the dependent variable. We're here to answer any questions you have about our services. The charges on R groups maintaining a structure of the active site are essential for the formation of the E-S complex. The state of ionization of the amino acids is altered when the pH is changed. Control of activity. s Illanes e School of Biochemical Engineering Ponti? All work is written to order. The study of the rate at which an enzyme works is called enzyme kinetics. 3mm.This in turn shows that there is a negative correlation and therefore showing that the rate of reaction is decreasing. Effect of pH. I will take the reading of where the red dye is. 3mm. a is used as a subscript for pharmacokinetic parameters appropriate to the distributive phase, e.g., t 1/2a, V da, etc.. Cf. Research question Investigation on the effect of different substrate concentrations, which in this case are the manipulated hydrogen peroxide concentrations on the rate of enzyme activity of catalase in liver on the decomposition of the hydrogen peroxide. A2. When the red dye was inserted into the odometer, air bubbles were frequently produced and this would have affected my results if I didn’t correct it. : 30.1.1. Note that the hydrogen peroxide only needs replacing when the pH is altered and should not be replaced between repeats at the same pH value, Measuring cylinders – 2 x 50ml (± 0,05ml), Stopwatch – the iPhone app was used since it was deemed easier to use than the analogue stopwatches provided by the school (± 1 second), pH buffer – 15ml each of pH 4, pH 6, pH 8 and pH 10, Paper discs – 25 (plus ample spare discs in case of mistakes), Forceps – thoroughly cleaned beforehand, Stopwatch inconsistencies – because it is the one that directly influences the final results in the largest way, given that the average human delay in reaction time is approximately 0.25 seconds for a visual stimulus. Free resources to assist you with your university studies! Rate of reaction increases due to more kinetic energy and more collisions. It had a minimal effect as the results are reliable and also the curve of best fit is reliable. We've received widespread press coverage since 2003, Your UKEssays purchase is secure and we're rated 4.4/5 on reviews.co.uk. 4. 7mm. Polyphenol oxidase (the enzyme) is pH dependent. s Illanes e Editor Enzyme Biocatalysis Principles and Applications 123 Prof. Dr. Andr? location (ONLY if a field experiment), As there is an increase in H+ they bind with the negative charges in the active site, stopping the substrate binding with the enzyme. My conclusion that I came up with was that as pH increased, the rate of reaction of the enzyme increased, and then at pH 7 it reached its maximum, and as the pH’s increased after, the rate of reaction decreased. Then I will inject the red dye into the monometer by using a clean syringe and make sure there are no bubbles in the monometer. At high temperatures, the enzyme gets denatured and at low temperatures, the enzyme is deactivated. I will measure temperature as I know it will affect enzymes and the rate of reaction. pH is also a factor in the stability of enzymes.nAs with activity, for each enzyme, there is also a region of pH optimal stability. The purpose of this chemistry laboratory exercise is to observe the effects of acids and bases on the rate of browning of apples when they are cut and the enzymes inside them are exposed to … Hence the data was clustered around the mean, illustrating the fact that there were no wild variations. The standard deviation for pH at pH 6 for example: The mean is equal to 6.726 and the sum of all deviations from the mean is 1.0172. Claim: This consistency is perhaps down to the fact that following the pilot study, where we found the stopwatch quite difficult to use accurately, the iPhone app was used instead – something which enabled us to be far more precise and to obtain more reliable results. Looking for a flexible role? I will also be using the same number of potatoes, same variety of potatoes, same mass of potatoes, to indicate I am using the same enzyme concentration. I will be keeping the temperature the same as it is difficult to control and is a limiting factor, and so to record results and minimize fluctuations I will do the experiment at the same time of day. Enzyme Activity. But overall this proves that there is a positive correlation between the increase in pH and the rate of reaction.

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