Systematic Error Lab Report

There is a large amount of catalase found in a human liver. Does the liver break down more hydrogen peroxide in the summer or winter? Explain your answer.

This experiment looked at how substrate concentration can affect enzyme activity. In this case the substrate was hydrogen peroxide and the enzyme was catalase. Pieces of meat providing the catalase were added to increasing concentrations of hydrogen peroxide in order to measure the effect of hydrogen peroxide concentrations on the enzyme’s activity. The variable measured was oxygen produced, as water would be too difficult to measure with basic equipment.

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.

The differences for the rates of reaction between the liver and potato are accounted for because liver contains more catalase enzymes than potatoes. This is because the liver is responsible for ridding toxins out of the body and as a result needs more catalase enzymes to do so; explaining the bigger reaction it had with the hydrogen peroxide.

Hydrogen peroxide is a toxic byproduct of cellular functions. To maintain hydrogen peroxide levels the catalase enzyme deconstructs hydrogen peroxide and reconstructs the reactants into oxygen gas and water. The catalase enzyme is found inside cells of most plants and animals. Regulating the levels of hydrogen peroxide is crucial in homeostasis and analyzing it’s optimal conditions for performance is just as important. To understand the optimal environment for this enzyme, they are put into different environments based off protein activity (enzymes are proteins). Catalase samples will be put into different hydrogen peroxide environments based off pH and temperature. The more active the enzyme, the more oxygen and water it will produce. Enzyme activity can be seen through the release of oxygen in the hydrogen peroxide. Since oxygen cannot be accurately measured, the data will consist of the longevity of the reaction in different environments. If the pH is higher than 7, then the reaction rate will increase due to the ample amount of hydrogen ions in the hydrogen peroxide. However the pH level cannot be higher than 10 or else there will be too many hydrogen atoms in the peroxide for the enzyme to be able to deconstruct them. If the temperature is increased, then the reaction rate will increase due to the ample amount of energy and movement in the hydrogen peroxide and enzyme.

Controls- The control in this experiment was very important because if it was not contained, then the data would have been faulty. It was very difficult to keep

To begin the experiment, six 16 x 150 mm test tubes were chosen, three marked “enzyme” and three marked “substrate.” For the baseline test using a 10 mL syringe and two 5 mL syringes, 7 mL of distilled water, 0.2 mL of a 0.3% guaiacol solution, and 0.3 mL of 0.1% hydrogen peroxide were added to the first substrate tube, containing a total volume of 7.5 mL. The baseline substrate test tube was then covered with a piece of Parafilm and gently mixed. To the baseline enzyme test tube, 1.5 mL of the standard 25g/400 mL concentration of peroxidase and 6.0 mL of distilled water were added; a piece of Parafilm also covered the tube then the test tube was gently mixed. The other two substrate tubes, one for the low concentration test and one for the

We did this by placing 20 mL of 0.3% hydrogen peroxide into a small test tube. Once this had been completed, 1mL of diluted catalase was placed into the small test tube. Quickly, we placed a large test tube over it and inverted the tubes, then measured the amount of oxygen immediately. This experiment included the mean, standard deviation and three t-tests set at

The percent error of the lab of my partner and I can be attributed to the small amounts of air that made it into the graduated cylinder and the confusion we had with massing the lighter. If I were to do the lab again I would submerge the cylinder more carefully and read the directions more

The purpose of the Anatomy and Chemistry of the Human Liver Lab is to understand and observe the functions of the liver in the human body. Throughout the experimentation process, the goal of the lab was to recognize the function of the liver when the organ becomes exposed to hydrogen peroxide and be able to classify the chemical reactions that take place during the process. My original prediction, or hypothesis, is: if a section of a liver, accompanied by a catalase, is exposed to hydrogen peroxide then the chemical reaction that will occur will be decomposition and exothermic. During the experimental process, three trials were performed and recorded with equivalent amounts of chicken liver, weighing .55 grams each, while reacting in the same amounts of hydrogen peroxide,10 mL. Before performing our trials, we measured the constant temperature of the hydrogen peroxide, which was 23.7 degrees Celsius. The first trial began with a temperature of 23.6 degrees Celsius, and rose to a finishing temperature of 24.1 degrees Celsius. As for trial two, this experiment was performed the next day, and had a starting temperature of 24.6 degrees Celsius and ending temperature of 25.8 degrees Celsius. The third trial, also performed the next day, the starting temperature was also 24.6 degrees Celsius and the ending temperature was 26.3 degrees Celsius, measuring as the highest increase in temperature among the trials. The increase in temperature enabled the observation of energy in the

This seminar was presented by Dr. Alison Frontier of University of Rochester. She is a current chemistry professor and she also runs a website called “Not Voodoo”. In this seminar, she talked about some common lab mistakes that she has discovered after 10 years and shared some useful techniques that help to avoid them.

The first possible source of experimental error in this experiment was the fact that our lab setup was not working properly since it was giving the lab group different data which lead to a higher than usual percent difference. This may hvae been caused by faulty lab equipment. The second source could've came from the PASCO since our data was incorrect depsite having a correct set-up. The third source may have been a faulty curcuit board since the data was also incorrect. Every source could have been responsible for the high percent difference.

Three sources of error that might have led to the systematic error during the lab include: lack of insulation, lack of even heating, and loss of heat to the environment. First, in my experiment I had to set the sample foods aflame in a coffee tin, which would heat the water inside the soda can. There was a large amount of heat that escaped through the top of the soda can, which made the water have a smaller temperature change. Secondly, there was incomplete burning of food in my experiment. The marshmallows did not burn; instead they caramelized on the outside, so not all the energy contained was released. Incomplete burning also occurred with the animal crackers. Lastly, my inefficiency was caused by heat loss to the environment. When trying

A potential source of error can be the amount of fire that is used on the paper (soaking in the chemical). As there was no specific time that the fire remained on the paper (from the lighter), the fire could have affected the intensity of the initial spark on the paper. Resulting in a longer time period that the fire was active. This would then change the data that was gathered and it would affect how powerful each retardant seems. Another source of error can be the amount of water and dry chemicals that were used. As the same graduated cylinder was used for the measuring and pouring of the deionized water, the 2nd-4th trials may have had an extra amount of water as there were drops left over in the graduated cylinder. This can also a reason for the dry chemicals. As the

I read your comments on my lab report and understand why I missed the points that I did. I didn’t miss many points but the ones I did miss included simple mistakes like word choice. For instance, I wrote “by hand” at one point when I should have written “manually.” A similar mistake was when I noted that a wider variety of ages would lead to “…more conclusive results” when I shouldn’t have used this wording because our results were conclusive. My abstract had the most mistakes. I was more specific than I should have been. I included too many details and I now understand why they were unnecessary. Other than those few mistakes, my report was pretty solid. This is reassuring because I put a lot of time into it. I worked diligently to ensure