BIOL 1208 Fall 2014 Writing Assignment 1 Cover Sheet I certify that the writing in this assignment is my individual work and is my intellectual property It does not contain the ideas or writing of other individuals authors Date October 15 2014 Victoria Sills Author 10 Lab Section Sera Niehaus Lab Partner Lab Topic Enzyme Lab Substrate Concentration Introduction Enzymes serve as natural organic catalysts used to speed up reactions by lowering the reaction s activation energy Enzymes which are mostly proteins are very specific to the substrates they catalyze The substrate fits perfectly into the active site of an enzyme which is specific to that substrate Once the substrate binds to the enzyme the enzyme substrate complex is formed The reaction occurs and the products are released The experiment was carried out to investigate the effects of changing the substrate concentration on reaction rate We used three different conditions each one varying the concentration of the substrate Condition 1 had a 5 ml substrate concentration Condition 2 had a 2 5 ml substrate concentration Condition 3 had a 1 25 ml substrate concentration We prepared 3 trials of each condition and recorded their absorbance at every 30 seconds for 150 seconds Having 3 test tubes of each condition increased our accuracy of the results From there we calculated the concentration of each absorbance value using the equation Absorbance 0 0014 1 0905 mMolar concentration From the concentration values we calculated the mean and standard deviation from each trial of each condition Enzyme substrate concentration is an important topic to explore because enzymes effect all living organisms Our null hypothesis we formulated states that changing the concentration of the substrate catechol will not affect the rate of the reaction changing catechol to benzoquinone Our alternative hypothesis we formulated states that increasing the substrate concentration or catechol concentration causes the rate of the reaction or the rate catechol changing to benzoquinone to increase as well The rate of the reaction increases at a constant rate until it reaches its maximum and plateaus when all the catechol is used up Prediction Before beginning this experiment we predicted that increasing the concentration of the substrate will increase the rate of the reaction So we predicted that condition 1 with 5 ml of catechol will have the highest rate of reaction followed by condition 2 with 2 5 ml of catechol and last condition 3 with 1 25 ml of catechol We based our prediction off the knowledge that the more substrate in a solution the more opportunity for the substrate to bind to the enzyme and start and create a faster reaction than a solution with a lower substrate concentration Results Figure 1 This scatter plot graph demonstrates the relationship between concentration and time for our 3 conditions of substrate concentration Condition 1 the highest substrate concentration of 5ml had concentration values ranging from 0 016 mM at 0s to 0 157 mM at 150s Condition 2 with a substrate concentration of 2 5ml showed decreased concentration values from condition 1 with concentration values ranging from 0 01 mM at 0s to 0 132 mM at 150s Condition 3 with a substrate concentration of 1 25 ml showed a significant decrease from both conditions 1 and 2 with concentration values ranging from 0 008 mM at 0s to 0 129 mM at 150s Figure 2 In condition 1 with 5 ml catechol the average rate of the reaction was 0 0009 mM sec and the standard deviation was 5 7735x10 5 mM sec In condition 2 we decreased the substrate concentration to 2 25 ml catechol and the reaction rate slightly decreased to 0 00075 mM sec with a standard deviation of 0 000106066 mM sec compared to condition 1 In condition 3 we decreased the substrate concentration to 1 25ml catechol and the reaction rate slightly decreased again to 0 00068 mM sec with a standard deviation of 0 mM sec compared to condition 2 and a standard deviation of 0 00015556 mM sec when compared to condition 1 The main trends in all of our data was the increase in concentration over the 0 seconds to 180 seconds Also all 3 conditions showed the same trend that closer to 120 seconds the concentration values began to plateau or level off after most of the substrate had been used up in the reaction and the reaction was over Another trend in our data was that the rate of the reaction of condition 2 and condition 3 were much closer together than condition 1 This data supported that increasing substrate concentration also increases the rate of the reaction Results Conclusions The null hypothesis should be rejected because our data shows that increasing substrate concentration increased the rate of the reaction Condition 1 with the highest concentration of 5ml catechol had the highest reaction rate of 0 0009 mM s While condition 2 with half the value of catechol as condition 1 2 5 ml showed a lower reaction rate then condition 1 0 00075 mM s And accordingly condition 3 with 1 25 ml of catechol the lowest substrate concentration had the lowest reaction rate of 0 00068 mM s This data shows a direct relationship between substrate concentration and reaction rate so the null hypothesis is rejected Our predictions were fully supported by our data We predicated that increasing substrate concentration would increase the rate of the reaction That prediction would supported since the condition with the highest substrate concentration also had the highest rate of reaction Our other prediction that the rates of reaction would correlate with highest to lowest substrate concentrations was also supported by our data Our data showed 5 ml to have the highest rate of reaction followed by 2 5 ml to have the second highest rate of reaction and finally 1 25 ml to have the lowest rate of reaction In conclusion increasing the substrate concentration also increases the reaction rate because the more substrate the more enzyme activity and therefore a faster rate of reaction Results Conclusions What were the main trends or patterns in your data Describe them Attach a Figure Graph of your processed data mean 1 stdev not raw data The Figure must have a figure caption Figure must be generated in Excel Based on your processed data which hypothesis should be rejected Explain your answer based on the slopes of the lines Was your prediction supported Explain your answer