Rate Of Starch Lab Report

In the experiment we used Turnip, Hydrogen Peroxide, Distilled Water, and Guaiacol as my substances. On the first activity, Effect of Enzyme concentration of Reaction Rate for low enzyme concentration, we tested three concentrations of the turnip extract, and hydrogen peroxide. For the Turnip Extract I used 0.5 ml, 1.0 ml, and 2.0 ml. For hydrogen peroxide we used 0.1 ml, 0.2 ml, and 0.4 ml. We used a control to see the standard, and used a control for each enzyme concentration used. The control contains turnip extract and the color reagent, Guaiacol. We prepared my substrate tubes separately from the enzyme tubes. My substrate tube

Amylase experiment # 2 was done to see how the pH affected the efficacy of the enzyme. First we collected all of the materials that were necessary to make this experiment. We needed five clean test tubes, the following standard solutions, 1% Starch Solution pH 3,1% Starch Solution pH 5,1% Starch Solution pH 7,1% Starch Solution pH 9,1% Starch Solution pH 11

The topic of this lab is on biochemistry.This experiment was conducted to show how cells prevent the build of hydrogen peroxide in tissues. My group consisted of Lekha, Ruth, and Jason. There were used two different concentrations of hydrogen peroxide through this experiment , 1.5% and 3%. By testing two different types it is easier to understand how the H2O2 and catalase react with one another. To do this both the yeast, which was our catalase, and H2O2 were mixed together in a beaker. Each concentration was tested out twice for more accurate results . 1.5% concentrated H2O2 had an average reaction rate of 10.5 seconds while 3% concentrated H2O2 had an average reaction rate of 7.5 seconds. From this experiment we learned that by increasing the concentration of H2O2 and chemically combining it with a catalase it will speed up the reaction. Enzymes speed up chemical reactions . The independent variable in this experiment was the concentration of the H2O2. Some key vocabulary words are Catalase, enzyme, hydrogen peroxide ( H2O2), and concentration.

Tables 2,3,4,5 and 6 show that as duration increased the absorbance also increased for each pH. The solution in the conical flask became darker (yellow) in time this is because the substrate, p-nitrophenyl phosphate was catalysed by acid phosphatase, releasing Nitrophenolate anion. It was the Nitrophenolate anion giving off the yellow colour; the presence of this feature increases the absorbance rate. The addition of sodium hydroxide distorted the shape of the enzyme making it no longer effective in its function.

Lab six requires students to observe the effects of pH and enzyme concentration on catecholase activity. Enzymes are organic catalysts that can affect the rate of a chemical reaction depending on the pH level and the concentration of the enzyme. As pH comes closer to a neutral pH the enzyme is at its greatest effectiveness. Also at the absorbance of a slope of 0.0122 the enzyme is affected greatly. The pH effect on enzymes can be tested by trying each pH level with a pH buffer of the same pH as labeled as the test tube and 1mL of potato juice, water, and catechol. This is all mixed together and put in the spectrophotometer to test how much is being absorbed at 420nm. As the effect on enzyme concentration can be tested almost the same way. This part of the exercise uses different amounts of pH 7-phosphate buffer and potato juice, and 1mL of catechol mixed together in a test tube. Each substance is put in the spectrophotometer at a wavelength set tot 420nm. The results are put down for every minute up to six minutes to see how enzyme concentration affects reaction rate. The results show that the pH 8 (0.494) affects the enzyme more than a pH of 4 (0.249), 6 (0.371), 7 (0.456), and 10 (0.126). Also the absorbance is greatest at a slope of 0.0122 with test tube C that has more effect on the reaction rate, than test tube A, B, and D.

To improve the results from the experiment buffer solutions that were not whole pHs could have been used e.g. pH 4.5, 5.5 etc. This would have provided more reliable results as a wider range of results would have been produced. Using pHs with decimals would also help to more accurately determine the optimum pH as the optimum may have been above or below the pH stated in the hypothesis; 8. In this experiment however the optimum is taken at 8 because the graph does not rise again.

In this lab experiment the action of the enzyme Amylase was observed on starch (the substrate). Amylase changed the starch into a simpler form, the sugar maltose, which is soluble in water. Maltose then breaks down the glucose chains of starch in the pancreas and intestines. Amylase is present in human saliva, and begins to act on the starch in the food while still in the mouth. Exposure to heat or extreme PH (acid or base) will denature proteins. Enzymes, including amylase, are proteins; if denatured enzymes can no longer act as a catalyst for the reaction. In the presence of potassium iodide, starch turns a dark purple color; however maltose does not react with I2KI. The rate of fading of starch allows a quantitative measurement of reaction rate.

To prevent fluctuation in the pH, a solution known as a “buffer solution” was used in the experiment. Buffer solutions are mixtures of at least two chemicals which counteract the effect of acids and alkalis. Therefore, when a small quantity of alkali or acid solution is added the pH of the enzyme doesn’t change.

After the substrate solution was added, five drops of the enzyme were quickly placed in tubes 3, 4 and 5. There were no drops of enzyme added in tubes 1 and 2 and in tube 6 ten drops were added. Once the enzyme solution has been added the tubes were then left to incubate for ten minutes and after five drops of DNSA solution were added to tubes 1 to 6. The tubes were then placed in a hot block at 80-90oC for five minutes. They were then taken out after the five minute period and using a 5 ml pipette, 5 ml of distilled water were added to the 6 tubes and mixed by inversion. Once everything was complete the 6 tubes were then taken to the Milton Roy Company Spectronic 21 and the absorbance of each tube was tested.

The experiments involved PH buffers of different pH were added to potato juice, water, and the enzyme catecholase. The mixture was then subjected to spectrophotometer at a wavelength of 420nm taking the absorbance readings. In the second experiment, a phosphate buffer of PH 7.0 was used in different measures together with different measurement of potato juice and the enzyme catecholase then subjected to the spectrophotometer at a wavelength of 420nm. The data collected inform of table and analyzed using descriptive statistics such as line graph and later interpreted, showing that PH and enzyme concentration do affect the rate of enzyme reaction

In addition, enzymes are highly specific since they act on substrates, which bind within the active site usually through weak interactions.” (3) There are three main types of enzymes in our digestive system including amylase, protease, and lipase. In particular, these enzymes are classified based on their target substrates, and they are also produced by different parts of the digestive tract. Imagine when we take our first bite of a meal, the food then enters our mouth, which is the beginning of the digestive tract. We then chew the food to break it down into smaller pieces that are readily digested. Meanwhile, amylase, which is secreted by the mouth and found in the saliva, “begins to split long and complex starch (polysaccharide) into smaller and simple sugar such as maltose (disaccharide).” (4) Further digestion is also required to break down maltose into glucose (monosaccharide) with the help of maltase. As a consequence, “when we chew breads slowly and thoroughly, we taste sweet on our tongue because amylase in the saliva is breaking carbohydrates down into their component sugars.” (5) The equation for this process is represented as

To test the optimal pH, the starch and a buffer were combined at a specific pH level and tested the absorbance of a solution at various times. To resolve the reaction rate of a solution at various temperatures, the solution was put into water both

Amylase is an enzyme that is located in human saliva. It is solely accountable for breaking down starch as a way to start the breakdown of food and is one of the first steps of digestion. The time at which the enzyme starts the chemical reaction with starch is called the reaction rate. In order to study how amylase works against starch, this experiment consisted of two tests; each testing a different condition of amylase. The first test was to simply study the reaction between saliva and amylase and note the reaction rates. The second test was to see if increasing the pH would decrease the reaction rate or halt it all together. Saliva was collected, diluted, and tested for reactions between starch and amylase. Another sample of saliva was collected, diluted, and had its pH increased and tested for reaction rate. The findings after the experiment was conducted aligned with the original hypothesis. The change in pH did show a significant decrease in the reaction rate.

Most importantly, it’s very hard to give exact measurements for the agar cubes. Therefore, each group could have had varying sizes of cubes or the size could have differed from the one we said it was. For example, the cube with the dimension of 1cm could have been more or less than that. To improve the accuracy, we can use an electronic balance to make sure that the cubes with the same dimensions have the same mass to ensure that their sizes are equal. Moreover, we didn’t measure the amount of hydrochloric acid we put into the beakers within the groups as the only instruction we got was to pour it in until the cubes are covered. Having varied amounts of hydrochloric acid became a source of error in the experiment. Next time, we should put the same amount of hydrochloric acid into the beakers. We can do this by using a measuring cylinder. Furthermore, not taking into account the possibility of an outlier became a source of error in the experiment. Not taking out the outlier from the data or repeating it for that specific one will wrongly influence the average, which in turn will influence the standard deviation. This could lead us to think that the experiment was more or less reliable than it actually was. For example, for the cubes with 1cm dimension, one of the values was 209 seconds while the others were 596,790, 720,750 and 841 seconds. This suggests that an error has been made in that

Hypothesis: If we decrease the level of pH in the enzyme Amylase, it will not be able to denature the carbohydrates in the potato starch solution after 10 drops because enzymes are very sensitive to pH levels and lowering it too much will compromise its ability to break them down.