AP Biology. [Structured Inquiry]. Enzyme Lab Outline. For each of the sections
below, you will be writing in your lab notebook, you may need to do a little ...
AP Biology
[Structured Inquiry]
Enzyme Lab Outline
For each of the sections below, you will be writing in your lab notebook, you may need to do a little research & writing outside of class. You will have one week to complete this. “If you don’t make mistakes, you’re not working on hard enough problems. And that’s a big mistake.” ~ Frank Wilczek “Science: If you don't make mistakes, you're doing it wrong. If you don't correct those mistakes, you're doing it really wrong. If you can't accept that you're mistaken, you're not doing it at all." unknown 1. Preparation for Lab (Thurs.-Fri.) - refer to “What is Inquiry” handout • What factors affect the rate of an enzymatic reaction in general? Factor (variable)
Effect
Why?
Temperature Substrate concentration Enzyme concentration pH
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The specific reaction we will investigate is shown in this equation: H2O2
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H2O + O2
The enzyme catalase speeds up this spontaneous reaction – why? What does hydrogen peroxide (H2O2) do to/in living cells? The enzyme catalase is found in living cells - which type of cells? Are there differences in this enzyme based on species of origin? What predictions can you make about the differences between the enzyme catalase taken from different enzymes?
2. Lab set-up (Friday) • The products of this reaction can be measured in several different ways. • Most scientists measure results in at least two different ways so that they can confirm their results before proceeding to the next stage of investigation or publication. • Since oxygen is released as gas, general principles (such as gas displacement under water) can be used to quantify gas volume. A gas pressure sensor may also work. These procedures & materials will be demonstrated & practiced in class. • What are the principles behind these procedures? [may need to research] • What science practices do you anticipate using from the AP curriculum?
3. Data collection (Monday-Wednesday) • Establish a baseline measurement – collect data on the activity of catalase taken from a potato at a specific concentration on a solution of 1.5% hydrogen peroxide. • Pick a variable (see #1 above) – make a prediction about the results of changing that variable. Develop a procedure to measure the effects of changing that variable. [Remember to run multiple trials] • Run the experiment – make good use of group members and maximize the data collection during class time so that you will not have to repeat or supplement procedures before &/or after-school. • Record data in a table format in your lab notebook. • Pick a different variable (see #1 above) – make a prediction about the results of changing that variable. Develop a procedure to measure the effects of changing that variable. [Remember to run multiple trials] • Run the second experiment – make good use of group members and maximize the data collection during class time so that you will not have to repeat or supplement procedures before &/or after-school. • Record data in a table format in your lab notebook. • You MAY find it useful to share information about your procedure with other groups before spending all of your class time collecting data. The discussion board on the wiki has a discussion area for this purpose. Your lab report will need a section that describes your procedures, so use this opportunity to make sure you can explain your lab set-up clearly & concisely before turning in your report. I will respond to the discussion board, but I am not reading reports before due date. 4. Writing the report (due Fri. Oct. 12th) - I have scheduled Oct. 11th & 12th to be in the computer lab. •
Use the LABWRITE tutor from NCSU for a full description of each element listed below. The postlab link will help walk you through each section of the lab report. (http://labwrite.ncsu.edu/index_labwrite.htm)
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Introduction – background information on enzymes & the reaction used for your experiment
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Methods – describe your experimental design
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Results – data collected presented in tables and graphs with descriptions of errors, difficulties or other data related information
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Discussion – conclusions and evaluation of the experimental results.
