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UNIT 2: The Chemistry of Life Biology I DAYSHEET 23: Introduction to Enzymes Name _____________________________________ Date: __________ Bellringer: Directions: Use your reading strategies (underline, highlight and/or circle) as you review the passage below. pH & Solutions Active Reading: In class, we discussed three types of solutions: Acids, Bases, and solutions that are Neutral. How do we determine whether a solution is an acid, base, or neutral? That’s easy, we use the pH scale! The pH scale is a linear scale that runs from 0-14. Look at the scale below: 0 --------------------------------------------------7-----------------------------------------------14 Acid Base Neutral Substances with a pH below 7 are called Acids. Substances with a pH above 7 are called Bases. Substances with a pH of 7 are called Neutral. We need to add one more detail to this scenario: The pH scale actually measures the amount of HYDROGEN IONS (H+) that are present in a solution. The lower the pH value, the greater the amount of hydrogen ions (H+) present in the solution. Example: Solution A has a pH of 8. Solution B has a pH of 3. Because Solution B has a lower pH, it has a greater concentration of hydrogen ions present. The more acidic a solution is, the greater the concentration of hydrogen ions. 1. An unknown solution has a very high concentration of hydrogen ions present. Is this solution an acid or a base? _____________________________ 2. Most household cleaning products have a very high pH. Are most household cleaning products acidic or basic? ___________________________ 3. What is the only substance discussed in class that has a neutral pH? _______________________________________ Biology Objective: I understand that enzymes are necessary for maintaining metabolism and homeostasis in all living things Homework: HW23 due next class Activity 1: Cornell Notes Name: Period: Date: Biology Objective: Essential Questions #1: What is an enzyme? #2: How do enzymes work? #3: How does an enzyme’s shape help it speed up reactions? Notes: Enzymes are a type of _____________________________ Enzymes are made of _____________________________ Enzymes are __________________ = things that speed up chemical reaction Enzymes work by lowering ___________________________ energy= the energy needed to get a reaction started Lowering activation energy ______________________ chemical reactions! Complete the graph below to show how enzymes work: _____________________ = the molecule(s) an enzyme attaches to ____________________________ = part of the enzyme that fits the substrate An enzyme fits onto its substrate like a _____________________________ Label the following in the above picture: enzyme, substrate, active site Summary: ructure of a water molecule by filling in the blanks below! Directions: Use the graph below and your notes and answer the questions 1 2 1. Which letter(s) on the graph represent(s) the activation energy? ________ 2. Which line (1 or 2) on the graph represents a reaction with an enzyme? _________ 3. Which line (1 or 2) on the graph represents an uncatalyzed reaction? ________ 4. What do enzymes do? FLIP Lysosomes are responsible into breaking down food FLOP What is the function of the lysosome? molecules into even smaller molecules the cell can use for energy. They also help break down waste and old parts in the cell. Each cell contains many lysosomes. Each lysosome has specific molecules inside that help break down different substances. These molecules are called enzymes. Enzymes are proteins that act as catalysts. A catalyst is something that speeds up a chemical What do enzymes do? What are enzymes made of? A. monosaccharides C. amino acids B. fatty acids D. nucleotides reaction. Write what type of molecule the following enzymes All enzymes have the ending “ase” on their name, and you can usually tell what they break down by looking at the first part of their name. For example, lactase breaks down lactose, a sugar probably break down: Lipase breaks down ________________ Protease breaks down _______________ found in milk. All chemical reactions need some energy, called activation energy, to get them started. Some reactions don’t need much energy, while others need a lot. If a lot of activation energy is needed to get it started, it will be hard for the reaction to ever happen. That is why living things have enzymes. Enzymes speed up chemical reactions by lowering the activation energy, so that not as much energy is needed before the reaction can get going. Trace over the reaction with a higher activation energy in one color. Trace over the reaction with the lower activation energy in another color. Which line do you think represents the reaction that involved an enzyme? FLIP Enzymes speed up reactions by holding molecules in FLOP Example of enzyme and its substrate: place while they are joined together or broken Circle what could be the substrate for the enzyme shown here: apart. At the start of a reaction, the enzymes a. binds (attaches) to a specific molecule, called the substrate. The specific spot on the enzyme that attaches to the substrate is called the active site. b. As long as the enzyme is in good shape and can fit to the substrate, it will be a lot easier for the substrate to come together OR split apart. c. d. Why might the relationship between an enzyme and its substrate be compared to a “lock and key?” If something happens to an enzyme to mess up its shape, it will no longer fit the substrate and the What does it mean if an enzyme is “denatured?” reaction may happen very slowly or not at all! When an enzyme loses its shape, it is said to be “denatured.” Why might this happen? Well, all enzymes have specific temperatures and pHs where they work What might cause an enzyme to denature? best. If the temperature or pH gets too high or too low for that enzyme, the enzyme could denature. The enzyme ABCase catalyzes the following reaction: What will happen to ABCase if the temperature rises to 40 degrees Celsius? ABC A + B + C ABCase works best at a temperature of 35 degrees Celsius and a pH of 7 (neutral). What will happen to ABCase if the pH becomes more acidic (lower)? HW 23: Enzymes Name: ______________________________ Biology I Date ___________________ Enzymes & Chemical Reactions: Use your reading strategies to receive full credit for your work. Organisms must be able to quickly turn reactants in a chemical reaction into product. This speed helps to ensure proper metabolic function, which maintains homeostasis. This is a key characteristic of life! In class, we discussed speed bumps and their role regulating the speed of traffic on busy streets. Remember that speed bumps are designed to slow traffic down. We have a similar “bump” in biology! Although speed bumps are necessary when regulating traffic, they can be deadly in living things. The body must be able to lower these “bumps” to ensure that our chemical reactions happen as quickly as possible. Enzymes are special proteins designed to lower these “bumps.” In chemical reactions, these bumps are called ACTIVATION ENERGY. The higher the activation energy, the slower the chemical reaction! Enzymes increase the rate of chemical reactions by making these chemical speed bumps smaller. If a chemical reaction has an enzyme present, it is a CATALYZED reaction. Catalyzed reactions will always proceed faster than uncatalyzed reactions. 1. Which statement about enzymes is true? a. b. c. d. Enzymes are consumed during chemical reaction. Enzymes provide energy to activate a chemical reaction. Enzymes provide a site on which reactants can combine. Enzymes increase the concentration of reactant particles. 2. How are enzymes able to speed up biochemical reactions? a. b. c. d. They provide energy to the reactants. They absorb energy from the products. They lower the activation energy of the reaction. They increase the number of available reactant particles. Look at the graph below to answer questions 3-6. 3. Which of the chemical reactions has a lower activation energy in the graph above, the catalyzed or the uncatalyzed reaction? ______________________________________ 4. Which of the chemical reactions (catalyzed of uncatalyzed) in the graph above will happen at a faster rate? _____________________________________ 5. Which of the chemical reactions above (catalyzed or uncatalyzed) has an enzyme present? _________________________________ 6. Using the graph above, which chemical reaction will have a lower activation energy (with enzyme or without an enzyme)? ___________________________________