Liver Lab PDF

Liver Lab Enzymes - What are they, how do they work, and can we disrupt their function? Objective: To explore how enzymes function and how their function can be disrupted. Background: All organisms use enzymes to catalyze chemical reactions. An enzyme is a biological catalyst which increases the...

Liver Lab Enzymes - What are they, how do they work, and can we disrupt their function? Objective: To explore how enzymes function and how their function can be disrupted. Background: All organisms use enzymes to catalyze chemical reactions. An enzyme is a biological catalyst which increases the rate of a chemical reaction by lowering the activation energy required to start the reaction. Without enzymes, many of biological chemical reactions, like cellular respiration which supplies the body’s cells with the energy necessary for all life functions, would proceed too slowly to be useful. Enzymes speed up reactions by bringing reactants into close proximity to their substrates and increase the facilitation of their interaction. Write the highlighted material in your lab notebook. Liver contains a specific enzyme called catalase. Hydrogen peroxide (H2O2) breaks down into water ( ) and oxygen ( ) when exposed to sunlight. When catalase is added to hydrogen peroxide, the reaction occurs faster. Review: 1)​ Name the enzyme being studied in this experiment. 2)​ Identify the location of the enzyme in the human body. 3)​ Write the chemical equation that shows the reaction catalyzed by the enzyme. 4)​ Define enzyme and substrate. 5)​ Describe the function of a control situation in an experiment. Create and write a hypothesis about the exposure of liver pieces to each of the following conditions detailed below. A)​ The control situation: (If ______, then ____ because____.) B)​ The enzyme function situation: C)​ The temperature situation: D)​The pH situation: Materials: ​ Liver pieces​​ ​ ​ ​ Thermometers  ​ Well plate​ ​ ​ ​ ​ Sharpie ​ Hydrogen peroxide​ ​ ​ Tweezers ​ Deionized Water​ ​ ​ ​ Hydroxide solution ​ Ice bath​ ​ ​ ​ ​ Hydrochloric acid solution ​ Hot water bath​ ​ ​ ​ pH test strips ​ 10 mL graduated cylinder​ ​ pipettes (2) Procedures: Do not write in the lab notebook. Part 1 (control) 1)​ Obtain two small pieces of liver. 2)​ Place them into small wells labeled A1 and B1. 3)​ Add just enough hydrogen peroxide to well A1 to cover the liver. 4)​ Note the reaction. Draw and describe what you see. 5)​ For tube B1 add just enough water to cover the liver. 6)​ Draw and describe the reaction. Part 2 (enzyme function) 1)​ Label two more small wells C1 & C2. 2)​ Take the liver piece from well A1 and place it into well C1. 3)​ Add fresh hydrogen peroxide to the well, just enough to cover the liver piece. 4)​ Draw and describe the reaction. 5)​ To well C2 add a fresh (new) piece of liver and the hydrogen peroxide from well C1. 6)​ Draw and describe the reaction. Part 3 (enzymes and temperature) 1)​ Label three wells A2, B2, C3. 2)​ Add a new piece of liver to each well. 3)​ To well A2, add hot hydrogen peroxide, just enough to cover the liver. 4)​ Record the temperature. 5)​ Draw and describe the reaction. 6)​ To well B2, add cold hydrogen peroxide, just enough to cover the liver. 7)​ Record the temperature. 8)​ Draw and describe the reaction. 9)​ To well C3 add room temperature hydrogen peroxide, just enough to cover the liver. 10)​ Record the temperature. 11)​Draw and describe the reaction. Part 4 (enzymes and pH) 1)​ Label three more wells A3, B3, C4. 2)​ To twell A3, add liver, water, and hydrogen peroxide, equal parts of each to just cover the liver. 3)​ Dip a pH strip into the solution and record the observation. 4)​ Draw and describe any reaction. 5)​ To well B3, add liver, hydrogen peroxide, and hydrochloric acid, equal parts of each to just cover the liver. 6)​ Dip a pH strip into the solution and record the observation.  7)​ Draw and describe any reaction. 8)​ To wellC4, add liver, hydrogen peroxide, and sodium hydroxide, equal parts of each to just cover the liver. 9)​ Dip a pH strip into the solution and record the observation. 10)​ Draw and describe any reaction. Data: Create and label the data tables you need to organize the measurements and observations described in the Procedures section. Analysis: 1)​ List the evidence that illustrated that a reaction occurred. 2)​ Below is a graph which shows how enzymes work. Use the graph and what you know about enzymes to respond to the questions beneath the graph. 2a) What does an enzyme do to a chemical reaction? 2b) Is an enzyme used up during a chemical reaction? Identify the test tube which supports your response. 2c) An enzyme/substrate is often described as a lock and key. Describe this analogy, using your data as support. Conclusion: (respond in CER format) You are the lab technician for a university biochemistry lab. One of the teaching assistants (T.A.) wants to use 1000 ml of the enzyme catalase solution for one lab section of 10 groups of students conducting the above “liver lab”. Using your data from this lab, explain to the T.A. why 1000 ml is too much to ask for. (Hints: explain what catalase does, the conditions in which catalase works best, and why only a small amount of catalase will work.)