Enzyme Discovery

Living Environment Student Work Biochemistry Unit Lesson 15 Enzyme Discovery Name: Period ______Date : Laboratory Experience Worth 90 Lab Minutes Bridge Define the terms below: Objective: 1. Rate To have students discover different characteristics and factors that 2. Relationship influence enzyme activity.

Essential Question: What are some Use each of the above words in a sentence. characteristics of enzymes? What role does the environment (internal or external) play with regards to enzyme activity?

Mini Lesson

P a g e | 1 Living Environment Student Work Biochemistry Unit Lesson 15 Work Period Expectations We will be looking today at a specific enzyme called catalase which we use to break down toxins, like H2O2 that are common waste products of digestion. We will also be determining if there are other enzymes that may be present, other than catalase in living systems.

Directions: There are several stations set up around the room. You will use the materials and directions at each station in order to discover and analyze how enzymes work in our bodies. Your goal is to be able to: 1. Determine how you can identify an enzyme reaction taking place 2. Determine if enzymes are reusable 3. Determine if all biological systems have the same enzymes present 4. Determine how different pH’s effect enzyme activity 5. Determine how temperature can effect enzyme activity 6. Determine if fruit has enzymes other than catalase present

In this lab, each station represents a different procedure where you will collect data in order to determine characteristics of enzymes and environmental factors that will effect how enzymes work. At each station you need to make a prediction/hypothesis that is specific to the question being asked and each station has its own analysis section where you will use data to find the relationship and answer the question. Once you have finished you will complete an evaluation section that includes ALL 6 stations following the format we have used all year.

Work Period

P a g e | 2 Living Environment Student Work Biochemistry Unit Lesson 15 Station 1. Enzyme Reactions

Question: What does normal catalase activity look like?

Prediction/Hypothesis:

Follow the procedures at the station.

Data Collection

Table 1. Catalase Activity Substance Observations Temperature Change

Analysis

Station 2. Reusable Enzymes

Question: Are enzymes reusable?

P a g e | 3 Living Environment Student Work Biochemistry Unit Lesson 15 Data Collection

Table 2. Catalase Activity Liver and Hydrogen Observations Peroxide, Trial Number 1

Analysis

Station 3. Enzymes in All Things

Question: Are the same enzymes present in all systems (living and non-living) on Earth?

Follow the procedures at the station

Data Collection

Table 3. Rate of Various Reaction Times for Various Tissues Tissue Rate of Reaction Potato Chicken Apple Sand

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Station 4. Temperature and Enzyme Activity

Question: Does temperature effect enzyme activity?

Data Collection

Follow the rating scale: “-“ no reaction “+” slow reaction “++” fast reaction “+++” very fast reaction

Table 4. ______

Enzyme Treatment Rate of Reaction Liver, 37 C, Ideal temperature for enzyme reactions Liver, 0 C, Freezing

Liver, 100 C, Boiling

Analysis

Station 5. pH and Enzyme Activity P a g e | 5 Living Environment Student Work Biochemistry Unit Lesson 15

Question: Does pH effect enzyme activity?

Data Collection

Follow the rating scale: “-“ no reaction “+” slow reaction “++” fast reaction “+++” very fast reaction

Table 5. ______

Enzyme Treatment Rate of Reaction Liver, HCl Analysis Liver, Water

Liver, NaOH

Station 6. Enzymes Elsewhere

Since there was a negative reaction from the apples that we tested at station 1, I am not so sure that fruits have enzymes present in them. Can you help me figure this out?

Question: Do fruits have enzymes in them?

Data Collection Create your own data table for Table 6!

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Analysis

Evaluation

P a g e | 7 Living Environment Student Work Biochemistry Unit Lesson 15 Summary Directions: Answer the EQs

1. What are some characteristics of enzymes?

2. What role does the environment (internal or external) play with regards to enzyme activity?

Closing Directions: Predict what kinds of reactions enzymes are responsible for and where in our bodies we might find enzymes!

Name: Period ______Date : Independent Practice P a g e | 8 Living Environment Student Work Biochemistry Unit Lesson 15 An abstract is a narrative tool that scientists use when writing formal articles or reports on their work. It is a short writing, usually about 250 words, in which they talk about the purpose of their experiment, the data that they collected, an analysis of that data, and the impact that the data has on their work. Your task is to write an abstract for the enzyme stations lab. You will use the questions to help guide your purpose, your data and analysis to speak to the results, and the impact that the data will have on your learning about enzymes and biology.

A sample abstract has been provided for you below so you can see how it flows. This is an abstract that was submitted by a high school senior that entered a science expedition event, a type of science fair, in 2002. Do NOT focus on trying to understand the content (this was an AP Biology student) so much as the format and WHAT it was that they included in their work.

"The Listeria monocytogenes p60 Protein is not Essential for Viability in vitro, but Promotes Virulence in vivo" Author: Sina Mohammedi, 2002 UC Day nominee and runner-up Intracellular pathogens (agents which infect host cells), such as Mycobacterium tuberculosis and Listeria monocytogenes, cause very high mortality rates in the United States. Therefore, deciphering the mechanisms through which the pathogens cause disease is of great interest. Listeria infection of mice is a well-developed model system for studying the fundamentals of host-pathogen interactions. In vitro assays in animal cell cultures have helped show that Listeria causes illness by secreting molecules, called virulence factors, to the outside of the bacterial cell in order to affect the host organism. My work involves one such secreted protein, called p60. P60 is an antigen (an agent seen by the host immune system) implicated in regulated bacterial cell wall breakdown. The objective of this study was to examine two questions: first, is p60 essential to the viability of Listeria, as previously published? and second, is p60 a virulence factor in Listeria? To examine these questions, I contructed a Listeria strain lacking p60 (p60-). This new strain displayed no defect in viability. In fact, most standard in vitro pathogenicity assays were normal for p60-. However, when p60- was tested in a mouse (in vivo), a 1000-fold reduction in virulence was observed. This discovery suggests that p60 is indeed a key factor in the disease-causing ability of Listeria, but not essential for viability. Future studies will focus on the precise role of p60 in Listeria pathogenesis. This work increases our understanding of such diseases as tuberculoses, various food poisonings, and meningitis.

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