The effects of temperature on the action of the enzymes catalyse.

Fair test

In this Investigation I will keep constant the following;

The same surface area of the liver. I will use the mashed up form as it will be a faster reaction as there is more area to react on, as we have to consider the time span.

The same volume of hydrogen peroxide in each part of the Investigation.

The same size equipment e.g. boiling tubes as the readings for the results will be wrong if this is not constant.

Use the same method for each experiment so that there won't be any major differences. I will only alter the temperature.

Measure the temperature with a thermometer.

Do the experiment 5 times to ensure that there isn't an odd result. 5 times is reliable to use as you can distinguish if there is one odd reading and whereas if you do the experiment less that 4 times, your readings will be less dependable.

Safety

In this experiment to make sure everything will be safe I will be wearing goggles while carrying out the experiment. I will also be wearing a gown and gloves to ensure full protection as I don not want to take any risks.

Denaturing

Each enzyme is a protein with a specific shape. If heat is applied to a reaction which an enzyme is taking part in, the reaction will speed up. As the temperature of the reaction is raised too much however, the reaction will quickly be halted. This happens because rising the temperature eventually makes the enzyme change shape. When the enzyme changes shape it can no longer catalyse reaction because the reacting particles can't fit onto the surface of the enzyme when this happens the enzyme is said be denatured.

Temperature

Particles have more energy as they travel faster. Some colliding particles just bounce off each other. As the temperature soars the particles are moving fast this makes particles collide more frequently in a certain time and makes it likely that collisions result in a reaction. Increasing the temperature of a reaction increases the rate of a reaction. At the higher temperatures reactant particles move more rapidly and collide more frequently and more aggressively.

How each part of the apparatus did I use?

Ice: To lower the waters temperature.

Measuring cylinder: To measure volume of hydrogen peroxide.

Thermometer: To determine the temperatures.

Kettle: To raise the waters temperature.

Ruler (30cm): To make measurements of the height of the foam.

Liver: To provide us the enzymes.

Test tubes: to hold the liver in.

Beaker: to accommodate the water in.

Hydrogen peroxide: to combine with the enzyme liver.

Results of Investigation

Test tube

Volume of hydrogen peroxide (h²o²) (cm³)

Temperature (ºC)

Height of foam (CM³)

Height of foam (CM³)

2

Height of foam (CM³)

3

Height of foam (CM³)

4

Height of foam (CM³)

5

Average of height of foam

A

5

0º

9.3

8.2

7.2

4.5

9.4

7.9

B

5

20º

2.0

7.2

6.4

5.9

2.9

6.88

C

5

30º

4.5

5.2

3.9

4.8

9.2

5.52

D

5

40º

8

9.2

5.9

6.2

7.9

9.44

E

5

50º

2.5

9.2

4.5

6.9

7.1

8.04

F

5

60º

9.5

0.9

1.2

0.1

9.1

0.16

G

5

70º

4.9

5.1

2.5

5.9

6.7

1.02

Conclusion and Interpretations

I expected these results because as the temperature is increases the height of the foam goes up. The height of the foam tells us how fast the reaction is going. As explained in the scientific theory the temperature increases the rate of reaction for the reasons given. The reaction peaked when the enzymes became denatured at 40ºC. I think that my results were accurate because I made a record of my work readings accurately and thoroughly. I would take readings at 5ºC intervals to get a consistent and accurate result. I didn't have any problems in maintaining the temperature while I was accurately interpreting the height of the foam. I also was able to read the measuring cylinder without any difficulty. Instead of measuring the height of the foam I could measure the volume of oxygen, this therefore gave a more truthful result. My results show me that as I decreased the temperature, the slower the reaction took to, my results went accordingly to the scientific theory. My results fluctuate this maybe because the liver might of not been the same size and given off more enzymes therefore reacting more with the hydrochloric acid consequently increasing the height of the foam.

Test tube

Temperature (ºC)

Height of foam (CM)

A

0

B

20

.8

C

30

5.5

D

40

.5

E

50

3.0

Collision theory

For a reaction to take place, the particles of the substances that are reacting have to collide. If they collide, with sufficient energy then they will react. There is minimum amount of kinetic (movement) energy that two particles need if they are going to react when they collide this is called the activation energy.

Equation Word:

Hydrogen peroxide oxygen + water

The chemical equation for this process is

2H O O + 2H O

² ² ² ²

Results of preliminary Investigation

Evaluation

I think the method was suitable for this experiment. The problem that occurred during the test was that I did not wash the test tubes to make sure that there were no remaining substances that could have affected other tests I redone my experiment which would have made my results more dependable. My measurements were likely to be inaccurate because the liver that was used to give off enzymes may have not given for the same amount each time, as it is very hard to make sure each bit of liver we used was exactly the same as one another. Another problem was that if the foam went higher than the test tube I would not be able to give an accurate reading. I think that if I were to do this experiment again the ways in which I could improve it are as follows; attractive looking graphs, a much more thorough description of things and more time, measure the liver twice to give a accurate amount each time and clean the test tubes after using them and do the experiment more times to give us a better and reliable result. The things that didn't go according to plan were my results of the experiment were not fair, so therefore I had to do the experiment again, this limited my time. By the time I had redone the experiment again and collected the results for a second time I had less time to finalize my coursework to hand it in on the deadline date given to me. Problems that I had were making an exact measurement on the height of the foam. As the foam bubbles was not all level. I resolved this problem by measuring the foam where most bubbles were instead of a couple on its own. If I had more time I would do the experiments more times to give and better synopsis and do more graphs to represent the data.