Vol of O2 - Optimum temperature
Temp
I am now going to use scientific theory to back up my hypothesis.
First of all I will use the ‘lock and key’ theory.
All enzymes are specific and there is one enzyme per function. The enzyme that I am investigating is called Catalase and its function is that it can only break down Hydrogen Peroxide. Just like no other enzyme will be able to break down Hydrogen Peroxide.
Catalase is found in potato or liver.
If the enzyme is heated up to say 45°C the active sit will change, but our substrate will stay the same.
We say that our enzyme has been denatured. The substrate no longer fits. What has happened to the enzyme is not reversible-it is permanent.
If we take another fully functional enzyme but this time cool the enzyme down, like before the active site will change and our substrate stays the same.
But this time what has happened to the active site is mot permanent. Heating up the enzyme can reverse what has happened to the active site. When the enzyme is in this cold state it is inactivated.
Something else to help back up my hypothesis is the collision theory.
This is my predicted graph again, but this time with two points marked on it-a and b. This is where the collision theory comes in, to back up what happens between these two points.
Chemical reactions only occur when reacting particles collide with each other with a certain minimum amount of energy. This energy is called the activation energy and results in reactants being converted into products.
Increasing the temperature of the reactants
The higher the temperature of the reactants, the greater the number of collisions so resulting in an increased rate of reaction (In my experiment this would mean that Hydrogen peroxide will be turned in to oxygen and water quicker) He is a diagram to illustrate this:
I have also found different wording on the collision theory that I have just explained. (And a slightly different diagram)
Chemical reactions only occur when reacting particles collide with each other with sufficient energy to react. As I found from before: The minimum amount of energy required to cause this reaction is called the ACTIVATION ENERGY.
When the temperature increases, the particles move faster, resulting in an increased number of collisions, and an increased rate of reactions. Also, the particles collide more energetically and therefore are more likely to react.
Enzymes
This is also some more research that I have done to help me with backing up my hypothesis-it is about the enzymes themselves.
Enzymes can be extracted from organisms in a purified form and then used in all sorts of scientific and industrial processes. An everyday use of enzymes in the home is in biological washing powders. A variety of protein-digesting enzymes are added to the powder. They are said to dissolve protein stains. The advantage of doing this is that the enzymes work at relatively low temperatures (about 37°, like I mentioned earlier). Working at low temperatures means that they can be used on delicate fabrics. But some people are allergic to them and they can also cause skin problems. Enzymes have many uses like: tenderising meat, skinning fish, removing hair from hides, softening vegetables, removing seed coats from cereal grain, extracting agar jelly from seaweed, making syrups, fruit juices, chocolates and other food products. All of the above jobs require different types of enzymes. So using an enzyme for making syrups to extract jelly wont work.
Some enzymes can work both ways. If two much of the reactant(s) is changed in to their product(s) the enzyme might change them back. Most metabolic reactions are reversible like this.
Here are the 5 important properties of enzymes:
- They are always proteins- this is one reason why we need proteins in our food.
- They are specific in their action. -Like I said earlier this means that each enzyme controls one particular reaction, or type of reaction.
- They can be used over again- this is because they are not altered by the reaction in which they take part.
- They are destroyed by heat-again like I said before this is because enzymes being proteins are denatured by heat. Most enzymes stop working if the temperature rises above 45°C. But some microbes have enzymes which can work at higher temperatures.
- They are sensitive to pH-this refers to the strength of acidity or alkalinity of a solution. Most intracellular enzymes work best in neutral conditions. However the digestive enzymes in the stomach work best in acid conditions), and those in the small intestine work best in alkaline conditions. (If I wanted to extend the investigation I could set up an experiment to see how acidic/alkalinity solutions affect how Catalase work)
With out enzymes the reactions that they perform would be so slow that life would grind to a halt.
Enzymes are made inside cells. Once formed the enzyme may leave the cell and exert (perform) its action outside. These enzymes that do this are called extracellular enzymes. They include the digestive enzymes that break down food substances in our gut (like the enzyme we are investigating)
Other enzymes exert their action inside the cell they are called intracellular enzymes. Their job is to speed up the chemical reactions occurring in our cells, but not only speeding up the reactions they also control them.
Anything that helps substrates to come into contact with the right enzymes will make enzyme-controlled reactions go faster. For example, raising the temperature will increase the random movements of the molecules and increase the chances of substrate and enzyme colliding-but the temperature must not be raised to much or the enzyme will be destroyed.