Enzymes are catalysts which speed up a reaction by providing an alternative reaction pathway of lower activation energy. But they do not undergo permanent changes and so they remain unchanged even at the end of the reaction. Many enzymes consist of proteins and non-proteins called the cofactor. The intra- and intermolecular bonds that hold proteins in their secondary and tertiary structures are disrupted by changes in temperature and pH. This affects shapes and so the catalytic activity of an enzyme is pH and temperature sensitive.
The basic mechanism by which enzymes catalyze chemical reactions begins with the binding of the substrate (or substrates) to the active site on the enzyme. The active site is the specific region of the enzyme which combines with the substrate. The binding of the substrate to the enzyme causes changes in the distribution of electrons in the chemical bonds of the substrate and ultimately causes the reactions that lead to the formation of products. The products are released from the enzyme surface to regenerate the enzyme for another reaction cycle.
Just as only the correctly shaped key opens a particular lock, so does only one enzyme reacts with a substrate. It is shown in the diagram above.
In the graph above, we can see that the x shows the optimal temperature (this is the right temperature for an enzyme to act at it fastest rate). We can also see that as the graph is making a progress and after it reaches the point x is gradually declines.
In this experiment I will show that as the temperature increases, enzymes start to denature. They need a suitable optimum temperature to react and after a certain temperature the enzyme denatures and the graph slops downwards.
• Test tube - 1 • Measuring cylinder – 1 • Water •
Bibliography: • IB biology textbook by Minka Peeters Weem with Christopher Talbot and Antony Mayrhofer. • Internal assessment worksheet. • Andrew Allot and David Mindoff – Biology Course Companion • http://www.rsc.org/education/teachers/learnnet/cfb/images/07A.jpg • http://www.rsc.org/education/teachers/learnnet/cfb/enzymes.htm • http://www.elmhurst.edu/~chm/vchembook/571lockkey.html • http://www.poolcenter.com/blog-enzymes-in-pools.jpg ----------------------- |ENZYME EXPERIMENT |What is the effect of different temperatures on the number of oxygen bubbles produced in a potato during enzymatic | | |reaction? |