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Integrating Lecture,
Laboratory, and Literature
using Case Studies
Ann T.S. Taylor
Chemistry Department
Wabash College
Crawfordsville, IN 47933
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What are your non-content
course goals?
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The Context: Che 361
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Required course for Chemistry majors
Most Chem minors also take the course
Organic II prerequisite
Typical enrollment: 24-30 students, 8-12
per lab section
• Three 50 minute class periods and one
three hour lab per week
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Che 361: Biochemistry
non-content goals
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Cooperative learning strategies
Transferrence and connections
Application, not only memorization
Cultivate intellectual curiosity
Requires critical thinking skills
Oral and written communication skills
Use bioinformatic and modeling tools
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Common features my cases
• A short real-life story
• Reading review and primary literature
articles
• Short in-class small group activities which
connect the case and lecture
• Laboratory activities that directly relate to
the case
• Computational activity
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The Case of the Tainted Tacos
A Case Study on Genetically Modified
Foods which integrates laboratory,
lecture, and literature
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Unit goals
Students should be able to:
• Explain transcription and translation
• Design PCR probes for a sequence of interest
• Understand how transgenic organisms are made
• Reinforce principles of enzymology, protein
structure, and membrane transport
• Resolve conflicting data sets
• Understand the broader ethical implications of
using GM foods
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The Case of the Tainted Tacos
The Setup Story
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Questions generated by story
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How are GM foods made?
How do GM foods “work”?
Are GM foods safe for the environment?
Could weeds become resistant to herbicides?
Are GM foods safe for humans?
Do farmers really benefit from using GM
products?
• Should I eat GM foods? Do I already eat GM
foods?
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Case teaching strategies
• Common study areas
• Specialization
• Jigsawing
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Questions all groups study
• What are the most common genetic
modifications of foods
• How genetic modifications are made
• How genetic modifications can be detected,
and how these methods work
• Design the primers that are used in the lab
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Specialist groups
Farmers
• Study the economic impact of GM foods and
how RoundUp Ready products work
Entomologists
• Study the mechanism of Bt products and their
impact upon other insects
Immunologists
• Look at methods to predict allergenicity
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Linking Literature
• Guided reading questions
• Small group problems
• Literature searches
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Example: Farmers
Read three papers, then answer questions such as:
• Why do farmers use genetically modified plants?
• When do farmers benefit economically from using GM
crops?
• Why does RoundUp (glyphosate) affect plants but not
animals?
• How does glyphosate affect EPSPS, both structurally
and kinetically?
• Describe in detail how weeds that are resistant to
RoundUp differ from wildtype (normal) plants.
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Economic impact of GM crops
Goals:
• Better pest
management
• Increase yield
• Reduce pesticide use
• More flexibility
Disadvantages:
• Only profitable when
infestation cost is
greater than tech cost
• Unknown effect on
soil ecology
• Development of
“superweeds”
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How does RoundUp work?
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Integrating technology
• Presentations
• Research techniques with guided
directions
• Tools and tutorials from the internet
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RoundUp Resistance
modeling
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Entomologist modeling
Protein
Slope of short circuit current decay
Wild type
(no mutation)
-13.8
R224A
-10.2
R228A
-9.6
R233A
-4.2
No cry protein
0
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Computational analysis of
Cry9 for allergenicity
• Does it have homology to known
allergens?
– BLAST search of allergen database
– STGSST (422-428) is identical to a sequence
in a Aspergillus fumigatus allergen
• Is the homology in a hydrophilic region?
– No—from a computational tool discussed in
one of the papers
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Linking lab
Do an experiment related to the issue!
• Sources:
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Adapt an existing lab
Adapt a “real world” technique
Adapt an experiment from one of the papers
Adapt a published teaching lab (Biochemistry and
Molecular Biology Education, Journal of College
Science Teaching, Journal of Chemical Education)
• Work on the case during lecture and lab
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Typical lab results
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Lane 1, Arrowhead Mills corn meal; lane 2, Kroger corn meal; lane 3,
Quaker white corn meal; lane 4, Cotton Pickin’ corn muffin mix; lane 5, Jiffy
corn muffin mix; lane 6,Gold Medal corn muffin mix; lane 7, Aunt Jemima
corn bread mix; lane 8, Martha White corn muffin mix; lane 9, nontransgenic corn seed; lane 10, Pioneer YieldGard corn seed.
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Break down of events
Lecture
Laboratory
Case
-Nucleic acid
structure
-Transcription and
translation
-Nucleic acid
methods
-Recombinant
DNA methods
-Making
transgenic plants
-Isolate DNA from
food samples
-Determine DNA
purity (A260/A280 )
-Set up PCR
-Read set-up story
-Divide into teams
-Read common
and specialist
papers
-Analyze PCR
results via
agarose gel
electrophoresis
-Group
presentations
-Ethics discussion
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Other examples
• Olestra case
– http://www.providence.edu/chm/kcornely/Cas
ebook.htm
– extract & digest lipids from potato chips
• Drug discovery
– HIV protease kinetic analysis
– structure exploration
– Drug discovery lab (BAMBED (2005) 33:
16 – 21)
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References
• Case study:
– Advanced version:
http://www.sciencecases.org/gmo/gmo_adv.asp
– GOB version:
http://www.sciencecases.org/gmo/gmo_gen.asp
– Also published in JCST (2005) 34(2):
• Lab experiments:
– Taylor, J Chem Ed (2005) 82 (4): 597-598.
– Brinegar & Levee BAMBED (2004) 32: 35-38.
– http://www.greenomes.org/
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Case study collections
• https://chico.nss.udel.edu/Pbl/ (requires
password)
• http://www.fhs.mcmaster.ca/pbls/writing/
• http://ublib.buffalo.edu/libraries/projects/ca
ses/ubcase.htm
• K. Cornely, Cases in Biochemistry, John
Wiley & Sons, 1999; also at
http://www.providence.edu/chm/kcornely/
Casebook.htm
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