This investigative case module was prepared as part of a BioQUEST faculty development workshop. The cases, resources, and implementation strategies were developed by participants for use with their own students. We invite you to adopt and adapt the following materials.

The BioQUEST Curriculum Consortium is committed to the reform of undergraduate biology instruction through an emphasis on engaging students in realistic scientific practices. This approach is sometimes characterized as an inquiry driven approach and is captured in BioQUEST's three P's (problem-posing, problem-solving, and peer-persuasion). As part of this workshop groups of faculty were encouraged to initiate innovative curricular projects. We are sharing these works in progress in the hope that they will stimulate further exploration, collaboration and development. Please see the following links for additional information:

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Investigative Cases
The Case: The Uninvited Guest

Julie's dad went in for a routine operation last week and she found out this morning that he picked up a bacterial infection. Although she initially thought that it would be no big deal, it turns out that this bug is resistant to several antibiotics. Two different types of penicillins were tried and neither worked. Now the doctors are going to try an exotic antibiotic but they say he has a 50/50 chance of making it.

"How can this be?" Julie asks. "Haven't antibiotics been used successfully for a long time?"

Case Author:
Walter Escobar Emory University:Center for Science Education

Case Analysis

1) How is it that penicillins work?

2) How do bacteria become resistant to penicillin?

3) How do drugs work?

Option: Include a know / need to know chart like the one below:

What do you know?
What do you need to know?

Learning Goals


We will study the enzyme beta-lactamase as a means of investigating both protein structure and function. This enzyme is produced by bacteria to breakdown penicillins. It is found in many common bacteria like Escherichia coli and Bacillus licheniformis. We will look at several beta-lactamase sequences and compare them to identify regions that are highly conserved. This will help us identify the substrate-binding site of these enzymes. Using Cn3D we will highlight these sequences and identify them in the 3D structure of beta-lactamase.

Study protein structure/function relationships.

Study enzymology taking into account substrates, products and inhibitors.

Study the development of antibiotic resistance in bacteria



Investigations and Activities

In the lab we can transform E. coli with pBR322 and then plate these bacteria onto media containing ampicillin.

We will take ampicillin plates and go to Lullwater Park. These plates will be inoculated with samples from the park to investigate the presence of ampicillin resistant bacteria.

We will grow up transformed bacteria and isolate crude preparations of beta-lactamase. The activity of these preparations will be tested with a spec 20.

Students will participate in the experimental design. They will be asked to think about appropriate controls for these experiments.



Biology, 6th edition (2002), J. Campbell etal.

Students will usually obtain additional references or resources
to help answer or explore their questions.

Special Data Items

1. bacteria.gif


Student Products

The students will write a report based on their findings.
The report will cover two aspects.

There will be a brief description of how bacteria become resistant to antibiotics and there will be another more extended description of the structure and function of beta-lactamases.

Background information will include information about the types of interactions that stabilize tertiary and quaternary structure.

A general description of the activity of enzymes and their interactions with substrates, products and inhibitors.

The report will include information about the mechanism of this enzyme and the role of catalytic residues of the active site.

Assessment and Evaluation Plan

The students will be evaluated on their participation in the classroom. They will be asked to work in groups of four in thinking about the case and answering the given questions.

Students will come up with their own set of questions and these will be shared. These questions will serve as a starting point for a resource search and these will also be shared with others in the course.

Students will devise an experimental design and turn this in for evaluation.

Participation in the initial process will be worth 20% of their grade for this module. The experimental design is worth 10% and their report will be worth the other 70%.



The case will be presented in class. We will then ask the students to break up into groups of four. They will be given questions and asked to discuss this. They will need to come up a list of new questions that will help them guide their course of action.

Students will be given a description of the lab and field exercise. They will be asked to submit an experimental design for their studies of beta-lactamase activity.

Students will be given a description of what to include in their report. Students will carry out their research and write their report. A first draft will be turned in for evaluation before the final deadline

Course name:
Biology 151
Likely sequence in syllabus:
Initial module to study protein structure and function
Time during term:
Within the first two weeks
This investigation will proceed over a week
The studies will occur in the field, lab, computer lab and lecture room
Students in course:
Collaborative elements:
Students will work in groups of four in the lecture and will work together as pairs in the lab and in the field.
Additional notes:



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