Enzymes Review

What are Enzymes? Acatalyst is a substance that speeds up a chemical reaction.Enzymesare biological molecules (typically proteins) that act as a catalyst for chemical reactions that take place within cells. They are needed for life and serve a wide range of important functions in the body, such as helping with digestion and metabolism.Some enzymes help break large molecules into smaller pieces that are more easily absorbed by the body. Other enzymes help bind two molecules together to produce a new molecule. Enzymes are highly selective, meaning that each enzyme only works with a specific shaped substrate.The specific action of an enzyme with a single substrate can be explained using a Lock and Key analogy. In this analogy, the lock is the enzyme and the key is the substrate. Only the correctly sized key (substrate) fits into the keyhole (active site) of the lock (enzyme).Smaller keys, larger keys, or incorrectly positioned teeth on keys (incorrectly shaped or sized substrate molecules) do not fit into the lock (enzyme). Only the correctly shaped key opens a particular lock. This is illustrated in the graphic below: Label the parts! Write them exactly as listed here: Enzyme, Substrate, Active Site, Product, Product Substrate Enzyme Active Site Product Product Naming Enzymes Most enzymes are easy to spot, as they commonly end with -ase. It is also usually easy to guess what substrates they work on depending on the first part of the name. For example, Sucrase is an enzyme that works on Sucrose (a sugar) and Lipase works on Lipids.Not all enzymes are like this, however. For example, the enzyme that breaks down starches (carbohydrates) is called Amylase. Fun fact: Amylase is in your spit. It is what helps break down food in your mouth. When you put bread in your mouth, you should notice that it will break down on its own. This is because the Amylase enzymes start breaking down the bread without you even chewing! Enzymes, Substrates, Products Complete the chart my filling in the enzyme for each substrate. You will click on the center boxes to see the options in the Word Bank. Match them to the molecules in the first column! Substrate (molecule to start) Enzyme Product (broken down into...) Lipids Lipase Glycerol Fatty Acid Maltose Maltase Glucose Proteins Protease Amino Acids Sucrose Sucrase Glucose Fructose Starch Amylase Maltose Optimal Conditions Enzyme activity can be affected by a variety of factors, such as temperature, pH, and concentration. Enzymes work best within specific temperature and pH ranges, and sub-optimal conditions can cause an enzyme to denature, or change shape and lose its ability to bind to a substrate.Temperature (Chart a): Raising temperature generally speeds up a reaction, and lowering temperature slows down a reaction. However, extremely high temperatures can cause an enzyme to lose its shape (denature) and stop working. The optimal temperature is the highest temperature that makes enzymes better before they start getting bad, so the TOP of the curve. The optimal temperature in the chart below is 35 degrees.pH (Chart b): Each enzyme has an optimum pH range. Changing the pH outside of this range will slow enzyme activity. Extreme pH values can cause enzymes to denature. As with temperature, the optimal pH range is when the enzyme is performing at its best. The optimal pH in the chart below is a pH of 7.Concentration (Chart c): Concentrationis just how much of something you have in one place. Increasing enzyme or substrate concentration will speed up the reaction, as long as there is not to many. If the concentration gets too high, it will not hurt the enzyme, it just will not become any more productive. As the chart shows below, the production just balances, it does not go back down. Enzyme Practice Questions An experiment was performed to test the effect of temperature and pH on the activity ofEnzyme X. The following data was collected during the experiment:Use the data to answer the following questions: 1) What is the optimum pH of enzyme X? 7 8 9 10 2) What is the optimum temperature of enzyme X? 10 20 30 40 3) Enzyme X performs critical life functions. Use the data above to explain why a fever of 40 degrees may be dangerous: It will make the enzyme move too fast, which will burn the person. It will cause the enzyme to denature, which means it will get bigger. It will cause the enzyme to denature, which means it will stop working. I will turn the enzyme into DNA, which will make it stop working. Using the 2 graphs above, at what pH do the following enzymes work best?Sucrase: 4Lipase: 8Pepsin: 3Trypsin: 8 Vocabulary Enzyme A protein that is a catalyst for chemical reactions. Substrate the substance on which an enzyme acts. Active Site the specific region of an enzyme where a substrate binds Product the substance that enzymes turn substrates into Vocabulary Part 2 Enzyme A protein that is a catalyst for chemical reactions. Catalyst A substance that speeds up a chemical reaction Optimum Temperature or pH at which the enzyme works best Denature When the active site of an enzyme changes so that the substrate no longer fits.