How does temperature affect enzyme activity?
In this practical investigation, my aim is to discover how temperature will affect enzyme activity, by looking at the rate of reaction.
I predict that the higher the temperature will be, the faster the reactions take place. However, I also think that there will be an optimum temperature, at which the reaction will work at its fastest; if the temperature goes beyond that, the reactions will stop altogether as the enzymes would have been denatured.
Scientific knowledge:
Enzymes are biological catalysts that speed up the rate of reactions without being used up. They are proteins that allow smaller molecules (substrate molecules) to fit within them. The area that these molecules fit into is called an active site. The active site has a very specific structure, and only the correct substrate molecule can fit within the active site for a chemical reaction to take place.
This simple action can be described using the lock and key theory/analogy. This is the hypothesis that describes the function of the active site and how the substrate molecule must be the perfect shape and fit inside the active site perfectly for a reaction to occur. If the substrate molecule cannot fit within the enzyme, it prevents a reaction to take place. This is illustrated in the diagram below (Figure 1):
However, enzyme activity is not always consistent – there are many factors that have an effect on the rates of reaction, as I am investigating. One of these factors (the one that will be explored) is temperature. There is an optimum temperature in which the enzymes work at their best and most commonly, the enzymes within the human body have an optimum temperature, and that is 37⁰C, however due to different conditions, the temperature varies. If the temperature it too cold for the enzymes, the reactions will be very slow. This is because there is less molecular motion in the enzyme and the substrate, causing there to be