Core Practical By Everjoy Kanyangarara

Everjoy Kanyangarara

Core practical: Investigating the effect of Temperature on enzyme activity

Hypothesis: temperature increases the rate of the enzyme-catalysed reaction but at a certain temperature the enzymes are denatured and temperature stops to have an effect on the reaction. This is a one-tailored hypothesis. Procedure: The equipment that were used in this experiment are: A measuring cylinder, container, water baths-24°C,40°C,60°C,80°C and an Ice bath, yeast cells, distilled water, scale, test tubes, gas delivery tube connected to a bung, hydrogen peroxide, stop watch, pipette,  Put water into the measuring cylinder and then place it face down in a container full of water and then record the making that the water gets to.  Measure out 0.1 grams of yeast cells on the scale and using a pipette measure 2cm³ hydroxide into a test tube  This is done under room temperature and at the time that I carried this experiment out it was 24°C  Connect the delivery tube to the measuring cylinder that is filled with water  Add the weighed yeast into the test tube containing the hydrogen peroxide and quickly bung the test tube at the same time using a stop watch record the amount of gas that is released within 30 seconds.  Measure the new level at which the water is at and then take this value from the original water level to know the amount of oxygen that is produced  Record the results into a table and then repeat the experiment twice with the same temperature  Repeat this experiment three time with all the other temperatures

Results: Repeats

Temperature 24°C

40°C

60°C

80°C

Ice 1°C

Volume of O₂ Produced 1

30

21

20

9

10

2

32

22

21

10

11

3

34

25

23

13

12

Table 1:

Table for the results that I collected at the different temperatures and the repeats that I carried out

Everjoy Kanyangarara

Everjoy Kanyangarara

Temperatu res

Volume of O₂ produced

Rate of reactions

30

1

32

1.06

34

1.13

21

0.7

22

0.73

25

0.83

20

0.67

21

0.7

23

0.66

9

0.3

10

0.33

13

0.43

10

0.33

11

0.37

12

0.4

24°C

40°C

60°C

80°C

Ice 1°C

Table 2:

Table for the rates of reactions for all the different temperatures used to carry out the experiment. Formula to work out the rate of reaction= (Volume of O₂ produced) ÷ (time) this was for 30 seconds. These are for all the repeats. Temperatur es 1°C

Mean Rate of reaction s 0.37

24°C

0.91

Everjoy Kanyangarara

Everjoy Kanyangarara

40°C

0.75

60°C

0.68

80°C

0.35

This is the table that I used to sketch my graph as I found the mean average rate of reactions for all the temperatures Table 3:

Graph 1: this is the graph for the temperatures plotted against their rate of

reactions. The scale for the temperature =1-13. 1 represents 1 then from there all the other values represent a number n*6. E.g. 4 is =24

Discussion: as the temperature increased the rate of the reaction increased. I say this is so because at the start when the temperature was 1°C the rate of reaction was 0.37 and as the temperature got to 24°C the rate of reaction increased to 0.91. As the reaction went on and the temperature got to 40°C, the rate of reaction started to decrease. This agreed with my hypothesis because for all the other temperatures the rates of reactions decreased. This showed that there is a positive correlation between the rate of reaction and the temperature. At 40°C onwards the rate of reaction started to decrease, this agreed with my hypothesis because the enzymes in the reaction became denatured around 24°C -26°C so the reaction was not taking place at a fast rate anymore. The rate at which kinetic energy was being produced was decreasing because the temperature was decreasing so there was less chance of the substrate and the active site colliding. So overall the rate of reaction will decrease.

Everjoy Kanyangarara