Biology coursework: Enzyme


Aim: Investigate the effect of one independent variable, enzyme concentration or the temperature, on the rate of the enzyme catalase.


The experiment that I am going to do is, to find the rate of reaction at different temperatures. My experiment is to cut the potato in to equal pieces then to put it into hydrogen peroxide, and then collect the reaction. I want to see which temperatures the enzyme work best. And use my experiment to prove my prediction is correct or wrong.


My prediction is that, the enzyme, potato, will work the best around 35C - 40C, the optimum temperature. And there will be less reaction happening in the higher temperatures like 90C- 80C. But the least volumes of oxygen to be produced would be at the lower temperatures, 10C 0C, were reactions occur slowly.


The low temperature would make the reaction happen very slowly because the enzyme does not get enough energy from its surrounding to collide with the substrate, hydrogen peroxide. So the reaction will happen slowly therefore little oxygen will be produced.


Moreover, in the high temperatures 60C and above, the hydrogen peroxide temperature would be too high so therefore the enzymes would denature. Denaturing is when there is too much thermal energy and the bonds in the enzymes vibrate so much that they break and deform, therefore changing the shape of the enzyme, which means that it can no longer fit into the substrate. If the enzyme denatures then little reaction would occur because there would be fewer enzymes for the substrate to collide into, therefore less oxygen would be produced. However, it would be interesting to see if the denatured enzyme or low temperature enzyme which produces more oxygen. Figure 1.1 shows how the substrate and enzymes collide.


In addition, for optimum temperature like 40C, the temperature would be perfect for a reaction to take place. It would prefer temperatures are 35C to 40C, this is when the work at their best. Therefore, the enzyme would collide with the substrate and I would most likely get the most volume of oxygen. Figure 1 will help me prove my prediction


Rate of reaction at different temperatures.





















Figure 1.0: (on the previous page) shows the rate of reaction of an enzyme at different temperatures.


The substrate is hydrogen peroxide, and the enzyme is the potato.
The substrate and enzyme have complimentary shapes, so that the hydrogen peroxide will fit in to the potato perfectly.
The perfect fit of the enzyme and the substrate is called the lock and key.


Figure 1.1: (Above) show us how the enzyme and substrate meet and then lock together.

Hydrogen peroxide (H2O2) is made up of two hydrogen atoms and two oxygen atoms. Hydrogen peroxide should really be called hydrogen dioxide. H2O2 looks like water (H2O), but that extra oxygen molecule makes this natural water additive one of the most powerful oxidizers known to man. Hydogen peroxide is also used kills bacteria, viruses and fungi.


Hydrogen peroxide is a harmful substance but it is being produced in the body?

Hydrogen peroxide is made by quite a few enzymes in the body. In particular, some enzymes breaking down certain amino acids and fatty acids make significant amounts of hydrogen peroxide. Since hydrogen peroxide can be damaging to normal
tissue, these enzymes are kept inside specialized organelles inside cells
called peroxisomes. The peroxisomes also contain large amounts of catalase
to break down the hydrogen peroxide before it can escape.



Hydrogen Peroxide is produced in the body in different amounts for different purposes. It is part of a system that helps you use the oxygen you breathe. It is part of a system that helps your body regulate all living cell membranes. It is important in the regulation of blood sugar and the production of energy in all cells. It helps regulate certain chemicals necessary to operate the brain and nervous system. It is used in the defence system of the body to kill bacteria, virus, yeast, and parasites. It is important in regulating the immune system. Scientists are finding more and more useful uses of hydrogen peroxide.


Hydrogen peroxide can help and some times cure some diseases; heart and vessel diseases, like poor circulation, heart arrhythmias, Cardiovascular Disease.


Asthma, Bronchiectasis, Emphysema,


Infectious Diseases, Immune Disorders, Migraine Headaches, Parkinsonism.