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Pectinase Lab

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-Abhirath Singh 9C Effect of Temperature on Pectinase - Experiment Aim: To determine the effect of temperature on pectinase, that in turn has on effect on the digestion of an apple. Hypothesis: The body temperature of a human is between 30�C - 40�C. Thus, we predict that this is the optimum temperature range where the pectinase will produce the most amount of apple juice. Background: Enzymes are biological catalysts that speed up chemical reactions without being utilized themselves. There are different types of enzymes that our produced by the body, for different types of food. eg. Lipase breaks down lipids, Protease breaks down proteins, carbohydrase breaks down carbohydrates and Pectinase breaks down pectin (found in apples). Different enzymes have a different & specific environment that they best work in at their fastest rate. There are many factors that affect the rate at which enzymes work, like the pH, temperature, etc. of the environment the enzyme is working in. In this experiment, we would like to explore the affect of temperature on the rate at which enzymes work. Variables: Constant Variable- Type and amount of apple sauce, Type and amount of Enzyme, Amount of control (Water), Time. Independent Variable- Temperature Of combination of food and enzyme. Dependent Variable- Amount of Juice produced. Materials: Preliminary Lab:- 1. Apple - 1 2. Pectinase - 8 drops 3. Water - 8 drops 4. ...read more.


5) Add 8 drops of pectinase in one test tube and 8 drops of water in the other. 6) Hold the two test tubes in the plastic bowl for 20 minutes. During these 10 minutes, you must maintain the temperature of the test tubes by adding cold or hot water to the plastic bowl. Also make sure to keep the thermometer rod in the apple sauce and not touching any part of the test tube. 7) During these 20 minutes also spread the cheese cloths into two different funnels and place the filters above a measuring cylinder for each. Use water to moisten the cheese cloth so that it sticks to the sides of the funnel. 8) Once the 20 minutes are over, remove the test tubes out of the beakers and filter the apple sauce through a filter paper into the measuring cylinders respectively. Use a stirrer to ensure that all possible juice is squeezed out, making sure not to let any of the apple sauce to fall outside or into the measuring cylinder. 9) Once all of the juice has been collected in the measuring cylinder, read the volume of the apple juice in each measuring cylinder and record it in a data table. 10) Repeat steps from 1-10 again for temperatures 20�C , 30�C, 40�C, 50�C, 60�C & 70�C. ...read more.


Errors & Modifications: 1) The temperatures maintained were about � 3�C of the desired temperature. This could lead to an anomalous result. This can be modified by placing the testubes in a controlled water bath, which is set at the desired temperature. 2) All the apple juice may have not made it through the cheese cloth, giving us an erroneous result for our reading for the volume of the apple juice produced. This can be modified by making sure to squeeze out all the apple juice from the cheese cloth or by using apple sauce in a more liquid state. 3) The time alotted for the pectinase to react on the apple sauce was not ample amount of time, thus giving us inaccurate results. This can be modified by increasing the time for the pectinase to react on the apple to 3 - 4 hours. This way we will get more accurate results. 4) The thermometers were placed in the bottom half of the test tube. Thus we did not know the temperatures at the top half of the test tube which also contained pectinase. Thus, the teperature at which the pectinse was acting on the top half of the test tube may not have been the temperature that was desired, giving us inaccurate results. This can be modified by placing a thermometer at the bottom of the test tube and at the top, reducing the chance of any inaccurate results. ...read more.

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Here's what a teacher thought of this essay

3 star(s)

Overall, this report into an investigation into the effect of temperature on pectinase activity covers most of the key sections required in a GCSE practical write up. The student includes a rather brief introduction which lacked any detailed research, either concerning the enzyme or the effect of temperature on its activity. The method was described in detail and it was pleasing to see that the student had carried out some preliminary work. Unfortunately, this work did not flag up problems with the variety of pectinase used and consequently the results proved to be invalid. The control results in which pectinase was replaced with water, generated almost identical results to those using pectinase.

The analysis and conclusion sections were therefore rather confused and struggled to draw clear, valid conclusions from the data. This essay is, however, an excellent example of the value of carrying out controls alongside the experimental tubes since without these, it would be difficult to assess the validity of the results.

3 stars

Marked by teacher Ross Robertson 10/05/2013

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