Enzyme Worksheet PDF 2013-14

Enzymes We've been talking about various biological molecules and that they are needed for reactions in the body (DNA, Protein synthesis, Cellular respiration etc.) and how molecules can change. You should know that it doesn't happen on its own. If you leave a blob of protein in a petri dish will i...

Enzymes We've been talking about various biological molecules and that they are needed for reactions in the body (DNA, Protein synthesis, Cellular respiration etc.) and how molecules can change. You should know that it doesn't happen on its own. If you leave a blob of protein in a petri dish will it just break down to the amino acids? No. What will break down proteins? Enzymes! Enzymes are the biological substance (proteins) that act as CATALYSTS and help complex reactions occur everywhere in life. A catalyst is a substance that increases the rate of a chemical reaction by reducing the amount of energy needed to start that reaction. This is called lowering the activation energy. ACTIVATION ENERGY can be thought of as a hill that must be gotten over. When a catalyst acts, it lowers the energy required to get over the HILL and the reaction can proceed. An enzyme is an organic catalyst meaning that it is a protein that catalyzes reactions in living organisms. Most reactions in the body require enzymes LOCKS AND KEYS A door that is locked needs a key that is just the right shape to fit in that lock. Otherwise you're stuck in the cold. Enzymes work in a similar way. Enzymes complete very specific jobs and do nothing else. They are very specific locks and the compounds they work with are the special keys. Here's the deal... There are four steps in the process of an enzyme working. (1) An enzyme and a SUBSTRATE are in the same area. The substrate is the biological molecule that the enzyme will work on. (2) The enzyme grabs onto the substrate with a special area called the ACTIVE SITE. The active site is a specially shaped area of the enzyme that fits around the substrate. The active site is the keyhole of the lock. (3) A process called CATALYSIS happens. Catalysis is when the substrate is changed. It could be broken down or combined with another molecule to make something new. (4) The enzyme lets go. Big idea - When the enzyme lets go, it returns to normal, ready to do another reaction. The substrate is no longer the same. The substrate is now called the PRODUCT or products ENZYME CONTROLS Enzymes sometimes need to be controlled when done with their function. Other times they are controlled because of poisons. DENATURING occurs when the control changes the enzymes shape (1) TEMPERATURE: Proteins change shape (denature) as temperatures change. Because so much of an enzyme's activity is based on its shape, temperature changes can mess up the process and the enzyme won't work. (2) ACTIVATORS: Sometimes you need an enzyme to work faster and your body creates an activator. Other times you might eat something that acts as an activator. Activators make enzymes work harder and faster. Activators can help the enzyme bind to the substrate (3) pH LEVELS: In the same way that temperature can change the shape of proteins, the pH of the environment does the same thing. The proteins denature if too acid or too basic (4) INHIBITORS: Inhibitors either slow down or stop the activity of an enzyme. An inhibitor can be a COMPETETIVE INHIBITOR and block the active site or it can be an ALLOSTERIC INHIBITOR and bond to another spot causing the shape to change Remember - When the shape changes, the enzyme will not work the same way. A nasty example of an inhibitor is snake venom or cyanide. Mr. Martinez Biology 2013-14 Silva Health Magnet www.meestermartinez.com  Number: _______ Name ___________________________________________________ Period _____ Date ________________ Enzyme Worksheet A catalyst speeds up the reactions in organs, by reducing the amount of energy 1) What is a catalyst? ____________________________________________________________________ required for it to happen, meaning it reduces the activation energy. ____________________________________________________________________________________ An enzyme is a biological catalyst in an organism, that helps chemical reactions 2) What is an enzyme? ___________________________________________________________________ occur in life. ____________________________________________________________________________________ The active site is where the enzyme and substrate bind together 3) What is the active site and what is its job? _________________________________________________ and is shaped for specific substrates ____________________________________________________________________________________ ____________________________________________________________________________________ Substrates are reactants for chemically catalyzed reactions. 4) What is a substrate? __________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________ The product is the substrate after working with the Enzyme 5) What is the product? __________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________ 6) Explain how an Enzyme works using the terms from 1 – 5 ____________________________________ An enzyme acts as a biological catalyst by ____________________________________________________________________________________ speeding up the reaction and uses substrates ____________________________________________________________________________________ by working on them in the active site, and certain substrates can fit into certain enzymes. At the end ____________________________________________________________________________________ ____________________________________________________________________________________ of the process, the substrate becomes a product rather than a reactant. 7) What is denaturing and what causes it to occur? Denaturing is when an enzyme changes shape and a ____________________________________________ change in temperature or pH level can cause it to ____________________________________________________________________________________ occur ____________________________________________________________________________________ 8) What 4 things can affect the way enzymes work? Explain how each thing affects an enzyme. ________ 4 things that can affect the way enzymes work are activators, causing enzymes to work faster, change in ____________________________________________________________________________________ pH level, as they can denature if it is too acidic or basic, inhibitors, as they can prevent substrates from ____________________________________________________________________________________ ____________________________________________________________________________________ coming into contact with the enzyme, and change in temperature, changing the shape of an enzyme. ____________________________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________ A lock and a key could be used to described an 9) How can a lock and key be used to describe an enzyme? ______________________________________ enzyme because the enzyme houses a specific ____________________________________________________________________________________ shaped substrate. This would mean that an ____________________________________________________________________________________ ____________________________________________________________________________________ enzyme is a lock and the substrate is the key. ____________________________________________________________________________________ Enzymes generally bond with only one type 10) Why do enzymes generally only bind to one type of substrate? _________________________________ of substrate because they are the only ____________________________________________________________________________________ substrate that will fit into the active site. ____________________________________________________________________________________ Mr. Martinez Biology 2013-14 Silva Health Magnet www.meestermartinez.com 11) Label the following terms in the following picture c Enzyme___ d Product(s)___ a Substrate___ b Active site___ Graph 1 Graph 2 Graph 3 12) Using graph 1, explain how enzymes work. Include the term activation energy and compare the two Enzymes are biological catalysts meaning that they speed up curves, explaining which is with the enzyme. _______________________________________________ processes in organisms by lowering the activation energy. ____________________________________________________________________________________ In the first curve the activataion energy is higher while the ____________________________________________________________________________________ ____________________________________________________________________________________ bottom one is shorter. This means the bottom one is with ____________________________________________________________________________________ the enzyme because it has lower activation energy. 13) Using graph 2, explain how temperature affects enzyme activity. Use the word denature._____________ ____________________________________________________________________________________ Temperature affects enzyme activity because when it isn't at optimal temperature there is not much activity occuring within ____________________________________________________________________________________ the enzyme. This is because when the temperature is too cold or hot the enzyme will denature preventing any activity to occur. ____________________________________________________________________________________ ____________________________________________________________________________________ 14) Using graph 3, explain how pH affects enzyme activity. Relate to temperature effects.______________ pH level affects enzyme activity because when it isn't at optimal pH levelthere is not much activity occuring within ____________________________________________________________________________________ ____________________________________________________________________________________ the enzyme. This is because when the pH Level is too acidic or basic the enzyme will denature preventing any activity to ____________________________________________________________________________________ occur. ____________________________________________________________________________________ Mr. Martinez Biology 2013-14 Silva Health Magnet www.meestermartinez.com