What Effect Does The Temperature Of Water

In this investigation I am going to mix a certain amount of rennin solution and milk, and record how long it takes the mixture to coagulate. I will repeat this procedure of mixing the rennin and milk when they are heated to 5 different temperatures and will leave them to coagulate in a water bath so as to maintain their temperature. I will repeat each temperature 3 times, calculate an average time of coagulation for each temperature and I will hopefully find a correlation between the temperature of the mixture and the time taken to coagulate and therefore come to a conclusion to my title question.I will use my existing scientific knowledge to make a prediction and to help me understand and explain the outcome once I have gained my results. Enzymes are biological catalysts.

They speed up a reaction without affecting the nature of the end products. Enzymes are specific and an enzyme will only work with a particular substrate. Rennin is an enzyme. So in the context of this experiment the enzyme, rennin, is speeding up the reaction of coagulation when the enzyme solution is mixed with milk.

There are many factors which can effect the rate at which an enzyme works.In this experiment I am testing the effect that change in temperature has on the rate of reaction. Diagram to show the process of enzyme reaction When discussing the effect of temperature on enzymes, there are two main points to consider - the collision theory and denaturing of the active site. The Collision Theory When the enzyme solution is at a low temperature, the molecules are moving relatively slowly. This means that there will be few collisions between the enzyme and the substrate and therefore few enzyme-substrate complexes will be formed, so the reaction rate will be fairly slow.

As the temperature rises there is more kinetic energy so the enzyme and substrate molecules will be moving faster. This results in there being more collisions between substrate molecules and the enzymes active sites and therefore more enzyme-substrate complexes are formed. This means the substrate molecules are broken up quicker and the reaction rate is therefore faster. This increase of reaction rate continues with the increase of temperature until the enzyme reaches it's optimum temperature and from then on the active site will begin to denature and the rate of reaction will slow.Denaturing of the active site Enzymes are proteins. Proteins are made up of a series of amino acids forming a polypeptide chain.

The order of these amino acids is called the primary structure of the protein. The secondary structure of the protein is the regular coiling or folding of the polypeptide chain forming an alpha helix or a beta pleated sheet. However the important thing to consider when exercising this investigation is the protein's tertiary structure. The tertiary structure of a protein results from 3D coiling of the already folded chain of amino acids.

It is formed by chemical bonds between the R groups of the amino acids and the protein folds into an irregular 3D shape. Proteins with tertiary structures are known as globular proteins. Since the sequence of amino acids is different in every protein, the bonds form in different places and therefore each globular protein has a different shape. This is why enzymes are specific. As can be seen in the above diagram, it is the active site of the enzyme where the reaction occurs.It is the shape of the active site that must be specific (due to the enzymes tertiary structure) so that the substrate fits into the active site and the reaction can occur.

The specific shape of the active site is due to the bonds between the R groups. However these bonds can be broken by high temperatures and therefore the active site can lose it's specific shape and become denatured. When the enzyme has become denatured, the substrate will no longer fit into the active site and therefore a reaction is not able to take place. This means as more enzymes denature due to increasing temperature, the rate of reaction will decrease.

Like the body, enzymes have an optimum working temperature. The optimum temperature for an enzyme is about 40 degrees Celsius. Our bodies stay at a temperature of around 37 degrees C which means enzymes in the body will always be working close to their optimum temperature and therefore as quickly as possible. It would be dangerous for the body to have a working temperature of 40 degrees C as if the temperature was raised even slightly, enzymes would start to denature. Graph to show the effect of temperature on the activity of enzymes PredictionHaving looked at the activity of enzymes and reactions in detail, I can make a knowledgeable prediction on the outcome of the experiment. I predict that as I increase the temperature of the both the milk and the rennin solution before and during mixing, the rate of reaction will increase.

This will be due to there being more kinetic energy as the temperature rises so more collisions between the enzyme and substrate molecules, more enzyme-substrate complexes formed and therefore a quicker reaction. This will be shown in my experiment by the time the rennin solution and milk takes to coagulate.However I also expect there to be an optimum point in my experiment where the enzyme works at it's fastest, and then as the temperature rises after that point I will expect the rate of the reaction to decrease due to the active sites of the enzymes becoming denatured so less enzyme-substrate molecules being formed and a slower reaction. I expect this optimum point to be about 40 degrees Celsius, as this is most animal/human enzymes optimum temperature. This will be shown in my experiment if the mixture that is quickest to coagulate is that nearest to 40 degrees Celsius.