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The point of this lab is to determine if a substance contains carbohydrates such as a reducing sugar and/or polysaccharides. This will be done by using Benedict’s reagent and Iodine stain tests. Benedict’s reagent will react to reducing substances in the solution by oxidizing it and changing the structure of the reducing sugar to form a colored precipitate. The color of this precipitate can be used to determine the concentration of reducing sugars in the substance. If the precipitate is blue no reducing sugars are in the substance. If the precipitate is bluish green, green, yellow, or orange it does contain reducing sugars. Iodine stain will be used to determine if the solution contains polysaccharides.…
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1. Fill in the following tables with your observations. Note if the test is positive or negative for the enzyme. Also note the appearance of the colonies and/or media. This will include: the color of the medium immediately surrounding the colonies after addition of iodine on PDA plate, whether bubbles were observed or not in the catalase test, the color of the urea slant, the color of the citrate slant, and whether the rabbit plasma remained liquid or became solid due to clot formation, etc. After each observation note which results indicate production of the given enzymes and which results indicate non-production of the given enzyme by placing a “+” or “-“in the appropriate squares.…
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By having a control in this experiment, we can see the changes with the presence of amylase. Lugol’s regent (I2Kl) changes color in the presence of starch, which is the control group that we have setup that demonstrates what would happen naturally, with starch and Lugol’s regent (I2Kl). The control group will have a distinct comparison available for us. As amylase, an enzyme that catalyzes the breakdown of the starch into glucose, which will have no reaction with Lugol’s regent (I2Kl) as well as no color change.…
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Experiment Results Predict Question: Predict Question: Do you think test tube 3 will show a positive Benedict's test? Your answer : a. yes Stop & Think Questions: You included tube 2 to Your answer : d. make sure there is no contaminating glucose in the amylase. Correct answer: b. see what a positive Benedict's test should look like. Which tube is included to detect contaminating amylase in the buffer or in cellulose? Your answer : b. tube 2 Correct answer: d. tube 4 What is the usual substrate for the pancreatic enzyme peptidase? Your answer : a. starch Correct answer: d. peptides Experiment Data: Tube No. 1 2 3 4 5 6 Reagent 1 Amylase Amylase Amylase Cellulose Peptidase Bacteria Reagent 2 Starch Glucose Cellulose Water Starch Cellulose Reagent 3 pH 7.0 pH 7.0 pH 7.0 pH 7.0 pH 7.0 pH 7.0 Time 60 60 60 60 60 60 Temp. 37 37 37 37 37 37 IKI + + + Benedict's ++ ++ ++…
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The purpose of this lab was to measure the extent of enzyme reaction on given substrates by means of color change. The reaction followed is given below:…
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We then repeated this in two more test tubes. We put one of the test tubes in ice (0 C) we put another in the water bath (42 C) then we put one in boiling water (100 C). We repeated the same thing for the boiled amylase. We then checked at five minutes to see if the starch had been digested by the amylase. We did this by putting a little of each of the six samples into a spotting tile. We then added iodine solution to this to see if starch was present or not. I could tell if starch was present or not because if the solution went orange it meant that there was no starch present, so all the starch had been digested, if the solution went blue/black it meant that there was starch present, so the starch had not been fully digested. We recorded the results in a table. We then waited another two minutes so that all together the starch solution had been in there seven minutes. We did exactly the same thing as we did at five minutes we also recorded these results in a…
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These biological macromolecules are to be identified by the changes in colour through three different tests - Iodine Test for starch and glycogen, Benedict 's Test for reducing sugars, and Biuret Test for Proteins. However, only two macromolecules are being identified in this experiment - carbohydrates and proteins. There are 12 solutions to be tested in this experiment. The Iodine test is used to indentify starch and glycogen in the given solutions. Of the 12 solutions, solution 8 is a starch solution and solution 7 is a glycogen solution. Starch solutions turn blue-black when Iodine solution is added to it. This is due to the formation of polyiodide chains when the Iodine solution mixes with starch. Starch contains both amylose and amylopectin. The amylose molecules in starch form helices at the locations where the Iodine molecules assemble. This cause a dark blue-black colour change ("Starch-iodine test", 2008). Therefore, solution 8 should turn blue-black when Iodine solution is added to it since it is a starch solution. However, glycogen solutions turn red-brown when Iodine solution is added. The chemical structure of glycogen is similar to the structure of amylopectin. Glycogen is highly branched. These branches are formed through acetal linkages. It is because of the highly branched structure of glycogen that solutions of glycogen turn red-brown in Iodine solutions (Ophardt, 2003). Thus,…
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Introduction: The Enzyme Lab is to conduct investigations to determine the most favorable conditions for the most efficient enzyme activity. Variables to be used testing include temperature, pH values and surface area. Enzymes are proteins that speed up the rate of chemical reactions, which would otherwise progress more slowly.(Background Information; pg. 1) pH is a measurement of the acidity or alkalinity (base) of a solution. When the liver got mixed with H2O2 , the first time the chemical reaction was fast, the second time the reaction was slow and the last try was very fast. Temperature is the degree or intensity of heat present in a substance or object. When the temperature of the liver changed from freezing to very hot to room…
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The purpose of this experiment is to identify three unknown enzymes. This is done by…
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The purpose of this lab experiment is to investigate factors that can affect the porcine pancreatic amylase enzyme activity in different environments such as the temperature, pH and also how being stored in extreme temperatures can affect the activity of the amylase. The activity of the amylase is going to be determined by the presence or absence of starch in the samples over time. There are some hypotheses on the Effects of temperature and pH; as I add the amylase to the starch in different temperatures the reaction’s rate increases in high temperatures; I belive that the amylase will work better. As the environment grows warmer, the amylase is going to become more energetic and more effective. Amylase is affected by environmental pH. I predict that the amylase activity will work best at a pH 7. As the pH changes from this point I predicted that the amylase activity is going to decrease and eventually stop. If I boiled and froze some amylase solution, and try to digest starch with at it at room temperature, I predict the previously-boiled and frozen amylase will not…
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Firstly, a source of error may occur during the Benedict 's test. Positive results may occur when their should not be. This is due to the fact that there may be a presence of another substance that can be oxidized other than reducing sugars. Furthermore, another source of error may be the dirty test tubes which may sway some reactions when solutions are mixed. Measurements may be another source of error. Such as using a plastic measuring cup can measure off by +/- 5%, and estimating the amount of solution in half a pipette. To improve this lab, and the Benedict test, another test should be done for non-reducing sugars that may give positive results. Another way to improve the lab is to use distilled water as a solution for comparision. The distilled water will not result in a positive control in the test due to the fact that water does not contain any macromolecules. The water can be compared with other solutions for a negative control. The results for iodine test indicate that solutions 1,2,3,4,5,6,9,10 and 11 turn yellow when mixed with iodine and therefore the solutions do not contain starch or glycogen. The yellow is a result from a colorless solution mixed with iodine. Solutions 7 and 12 turned red/brown when iodine was added. Conclusions can be made that these solutions contain glycogen. The highly branched structure reacting with iodine and gives it that red/brown color. Furthermore, solution 8 turned blue/purple which is an indication that it is starch, and it was also expected to result positive because it was 1% starch solution. Solution 7 therefore contains amylose and amyloepectin. But it is the amylose that initially reacts with iodine creating a blue color. Secondly, the results for the Benedicts test showed that solutions 2, 5, 7, 8, 9, 11 and 12 had a negative control. No color change. Therefore these solutions do not contain any molecules that can reduce cupic ions such as a reducing sugar. An…
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How does changing the surroundings of enzymes affect their reaction rate? The purpose of the experiment is to determine how different abiotic conditions affect the rate at which enzymes accelerate/cause reactions In this lab students measured the height of the foam after catalysis between catalase (enzyme) and 7 other (solutions) to determine which solution had the fastest reaction rate.. The control variable of the experiment would be the solution of only hydrogen peroxide, water, and catalase. The independent variables of the experiment were the abiotic factors such as PH level, temperature, and the amount of salt within the environment. The dependent variable of the experiment would be the height of the foam(product) after each change in environment. If I change the environment of the catalyst by adding high sodium, low sodium, and very low sodium into three individual test tubes , and measured the height of the foam then low sodium would have the highest reaction rate, this is because changes in the concentration of salt alter the electrostatic interactions between charged amino acids, so if salt is added the ability of enzymes to bind to the substrate is altered and the enzyme may or may not be able to bind to it. If I change the environment of the catalyst by adding room temperature , boiling , and freezing cold Solutions into three individual test tubes and measured the height of the foam then freezing cold Solution would have the highest rate of reaction this is because the higher the temperature the weaker the hydrogen bond. If I change the environment of the catalyst by adding acidic and basic solution into two individual test tubes and measured the height of the foam then basic would have the highest rate of reaction because the PH level also alters the electrostatic interactions doing the same as salt, when PH level is decreased the negative charge is neutralized, hydrogen bind to the unoccupied pair of electrons on the nitrogen…
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a. maximum of amylase is at pH 7.0 (tubes 2 & 5, brownish red) and pH 9.0 showed little activity (tubes 6 & 7, green)…
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To test the effect of a substrate concentration on enzyme activity, the amylase enzymes were combined with a different substrate concentration (starch) and the rate of the reaction was determined with the aid of I2kI. If starch was detected, the solution turned to dark blue; if the starch was already broken down, then reaction stayed colorless. To test the optimal PH, the starch and a buffer were combined at a specific PH level and the rate of reaction was tested. To determine the optimal temperature of amylase enzyme, the solution and amylases enzyme were held at various temperatures and the rate of reaction was determined.…
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