The Effect of Temperature on Enzymatic Activity. Aim To investigate enzyme activity of yeast on glucose at different temperatures

Time

Concentration of glucose

Materials

• •        100mL beakers x5 (label from A-E)
• •        5 cm3 syringes x5
• •        10 cm3 of 10% yeast solution
• •        15cm3 of 2% glucose solution
• •        1 thermometer
• •        2 hotplates
• •        Stopwatch
• •        Ice cubes x 6
• •        400mL water
• •        Observations chart & pen

Method

1. 1.        Place 6 ice cubes and 80 mL of water into Beaker A
2. 2.        Measure and record the temperature (should be around 10°C)
3. 3.        Fill 3cm3 of glucose solution into the syringe and then in the same syringe insert 2 cm3 of the yeast solution
4. 4.        Place the syringe into Beaker A (mouth facing up) and record the number of bubbles produced in 10, 15 and 20 minutes
5. 5.        Fill Beaker B will 80 mL of water at room temperature (20°C)
6. 6.        Fill 3cm3 of glucose solution into the syringe and then in the same syringe insert 2 cm3 of the yeast solution
7. 7.        Place the syringe into Beaker B (mouth facing up) and record the number of bubbles produced in 10,15 and 20 minutes
8. 8.        Set up a hotplate at 30°C
9. 9.        Fill Beaker C with 80 mL of water and place on hotplate

10.Fill 3cm3 of glucose solution into the syringe and then in the

     same syringe insert 2 cm3 of the yeast solution

11.Place the syringe into Beaker C and record the number of    

     bubbles produced in 10,15 and 20 minutes

12.Repeat steps 9-11 for 40°C and 50°C in Beaker D and E

Data

Raw Data

Processed Data

Data Analysis

From the data above it can be seen that the hypothesis was correct because the enzymatic activity did increase until the optimum temperature of 40°C was reached and started to fall after that point.

Conclusion

In conclusion my hypothesis was correct because the rate or enzymatic activity did increase to a point and then dropped. This is due to the enzymes having an optimum temperature at which they catalyze reactions most efficiently. It can be seen that the optimum level for enzymatic activity is at 40 degrees Celsius because that is the peak of the curve and any point before or after that point has less enzymatic activity. At high temperatures the molecules, the enzymes and the substrates, move around fastest, and thus there are the most collisions per second, causing enzyme-substrate complexes to be formed more frequently and thus have a higher rate of reaction. Points after the optimum temperature result in a lower rate of reaction because the enzymes start to get denatured and lose enzyme structure and thus the substrate (e.g. glucose molecules) cannot bind to the active site of enzyme. So the higher the temperature the most enzymatic activity there will be until the optimum temperature and any temperature after that will result in denaturation of enzymes and drop in enzymatic activity.

Evaluation