Enzymes Affecting Enzyme Activity
Independent Variable- different pH's in solution (4,7,10)
Dependent Variable- Pressure (kPa), reaction rate
Constants- amount of drops of yeast solution, temperature, amount of peroxide and pH in solution
Prediction: If the pH is too high or too low, then the rate of reaction will decrease.
Null: There is no affect on the rate of reaction because the optimal temperature stays the same despite the pH, so since the temperature (which affects enzyme activity )is staying the same, so should the reaction rate.
Alternative: There is an affect in the reaction rate because the pH can change specific bond interactions between the substrate and the enzyme which would affect the enzyme's ability to work at its maximum rate.
Bar graph- The solution with pH 4 has an average rate of reaction is about 0.01482 kPa/s. The solution with pH 7 has an average rate of reaction is about 0.06741 kPa/s. The solution with pH 10 has an average rate of reaction is about 0.0629 kPa/s. The solution with pH 7 has the highest rate of reaction with the solution with a pH of 10 coming in 2nd and the solution with pH 4 with the slowest reaction rate.
The experiment measured if there is an optimum pH which will make the enzyme rate of reaction work at its max.
The solution with a pH of 7 was the optimal pH to help the enzyme work at its maximum rate because it had the highest average rate of reaction (0.067412 kPa/s) compared the solution with a a pH of 4 (0.01482 kPa/s) and 10 (0.0629 kPa/s). The solution with a pH of 7 had the highest rate of reaction because it had the largest change in pressure over time. The bigger the change in pressure, the more chemical reactions are occurring between the enzyme and substrates because the enzyme (catalase in yeast) is breaking down the substrate (hydrogen peroxide) into water molecules and oxygen. A build up of oxygen leads to an increase in pressure; therefore, the more reactions, the more oxygen products, the higher the pressure, the higher the rate of reaction. With the other solutions of pH, the pH was more acidic or basic which hindered the bond interactions between the enzyme and substrate, so less reactions were able to occur, making less oxygen, having a lower pressure, and having a slower reaction rate.
Errors that could have occurred- The person holding the cap could have accidentally released some air during data collection by not keeping the cap completely secure, changing the pressure reading. The person holding the cap could have not put the cap on the tube after the yeast solution was added in the same amount of time each round, letting more air escape and getting a different pressure reading. The amount of yeast solution could have been different. The amount of drops of yeast solution was controlled, but one drop could have been larger than the others.
How experiment can be improved- Conduct more trials to ensure a better collection of data.