Classic Research Articles as Classroom
Texts for PBL in Undergraduate
Biochemistry
Hal White
Dept. of Chemistry and Biochemistry
University of Delaware
16 June 2012
University of Michigan – Dearborn
ASBMB NSF-RCN Meeting
Introductory Science Courses
Stereotype
1. Lecture format that is content-driven.
2. Abstract concepts introduced before concrete
examples.
3. Enrollments often more than 100.
4. Limited student-faculty interaction.
5. Grading based on a few multiple choice
examinations that emphasize recall of information.
6. Reinforce intellectually immature students to a
naïve view of knowledge.
Common Features of a
Problem-Based Approach to Learning
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Learning is initiated by a problem
Problems are based on real-life, open-ended
situations, sometimes messy and ill-defined.
Students identify and find the information
necessary to solve the problem using appropriate
resources.
Students work in small permanent groups with
access to an instructor.
Learning is active, integrated, cumulative, and
connected.
What Does a PBL Classroom Look Like?
Overview of This Presentation
• The Case for Classic Articles as PBL
Problems
• Example of an Article-Based Course
• Experience a Classic Article Problem
• Designing a Course Around Classic
Articles
• Student Response
Characteristics of Good PBL Problems
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Engage interest
Require decision and judgment
Need full group participation
Open-ended or controversial
Connected to prior knowledge
Incorporate content objectives
Classic Articles as PBL Problems
Advantages
• Authentic (not contrived)
• Complex
• Relevant to the Discipline
• Introduce Important Historical Figures
• Encourage use of Internet Resources
Science as Literature?
“There is no form of prose
more difficult to understand
and more tedious to read that
the average scientific paper.”
Francis Crick (1995)
Science as Literature?
“I am absolutely convinced that science is
vastly more stimulating to the imagination
than are the classics, but the products of
this stimulus do not normally see the light
of day because scientific men as a class are
devoid of any perception of literary
form”
J. B. S. Haldane
Introduction to Biochemistry
Relation to Other Science Courses
COO
COO
CH2
CH2
H3C
O
CH3
H3C
N
H
C
H
N
H
C
H
H
N
H
C
H
CH3
N
H
O
Biology
Chemistry
Provides the
methods and
molecular perspective
Provides
the relevance
Biochemistry
Provides the means to
evaluate and predict
Mathematics
Provides
physical models
Physics
Introduction to Biochemistry
Evolution of the Course
1970's Course for non-science majors
based on Herman Epstein’s model.
1989 Modified course initiated as part of a
new B.S. Biochemistry curriculum.
1993 Problem-Based Learning format
introduced.
1996 Undergraduate Tutor-Facilitators
used for the first time.
Introduction to Biochemistry:
An Article-Based PBL Course
• 3 Credits, No Laboratory, 8:00 AM MWF
• Theme - Hemoglobin and Sickle Cell Anemia
• First Biochemistry Course for Sophomore
Biochemistry Majors
• Required for the Major
• Taught in a PBL Classroom
• Enrollment 20 - 35
• Uses Juniors and Seniors as Group Facilitators
Classic Hemoglobin Articles
Read Before Spring Break
Stokes (1864)
Spectroscopy
Solvent Extraction
Zinoffsky (1886)
Elemental Analysis
“Jigsaw” Groups
Bohr et al (1904)
Gas Laws
Herrick (1910)
Medical Case
Conant (1923)
Electrochemistry
Svedberg & F (1926)
Sedimentation Eq
Peters (1912)
Stoichiometry
Diggs et al (1934)
Epidemiology
Pauling & C (1936)
Magnetic Properties
Adair (1925)
Osmometry
Produce
Concept Maps
Home Groups
Individual and Group MidTerm Exam
Classic Hemoglobin Articles
Read After Spring Break
Pauling et al (1949)
Electrophoresis
Ingram (1958/59)
Peptide Sequencing
Dintzis (1961)
Direction Protein Syn
Group
Work
Allison (1954)
Malaria Resistance
Individual
Project
Hemoglobinopathy
Assignment
Genetic Mutations
Protein Structure
Shemin & R (1946)
Heme Biosynthesis
Individual and Group Final Exam
Course Timeline
Before Midterm
1850
Stokes
After Midterm
1900
1950
Zinoffsky
Diggs
Bohr
Herrick
2000
Dintzis
Ingram
Allison
Pauling et al.
Shemin Hemoglobinopathy
Peters
Conant Adair
Pauling +
Svedberg
Assignment
Introduction to Biochemistry
Course Description
• Heterogeneous groups of 4 discuss and work to
understand about ten classic articles.
• Articles presented in historical context, show the
development of scientific understanding of
protein structure and genetic disease.
• Assignments and examinations emphasize
conceptual understanding.
• Instructor monitors progress, supervises tutors,
presents demonstrations, and leads whole class
discussions to summarize each article.
Introduction to Biochemistry
Instructional Goals For Students
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
Become intellectually independent learners
Recognize and confront areas of personal ignorance
Review and apply chemical, biological, physical, and
mathematical principles in a biochemical context
Improve problem-solving skills
Create, understand, and value abstract biochemical models
See biochemistry in relevant historical and societal contexts
Discover and use the resources of the library and the Internet
Gain confidence in reading and understanding scientific
articles
Experience the powers (and pitfalls) of collaborative work
Appreciate importance of clear oral and written communication
Learn to organize logical arguments based on evidence
Author of the first article students read.
Known for:
“Stokes Law”
“Stokes Radius”
“Stokes Reagent”
“Stokes Shift”
Sir George Gabriel Stokes (1819-1903) became Lucasian
Professor of Mathematics at the University of Cambridge in
1849. This prestigious professorship once was held by Sir Isaac
Newton and now is held by Stephen Hawking. Like Newton,
Stokes served both as president of the Royal Society (1885) and
as a conservative member of Parliament (1887-1892)
Instructions for Stokes (1864)
In groups of two or three, consider the
introductory section of the Stokes
(1864) article.
Assignment: Make a list of the
concepts and facts that your
students would need to know (or
review) in order to understand this
section.
Oxidation and Reduction of
Hemoglobin
CHEM-342 Introduction to Biochemistry
Question for Group Work on
Midterm Examination
Prof. Essigsaure returned to his lab one night to prepare for a lecture
demonstration based on the experiment presented in the second
paragraph of Section 11 in Stokes’ 1864 article. Within minutes he was
looking high and low for the glacial acetic acid and mumbling angrily
about associates who don’t replace the things they use up. Frustrated,
but undaunted, he figured any acid would do and substituted
concentrated hydrochloric acid. After all, he reasoned, a stronger acid
should work even better. — Not so. Sure enough the hemoglobin
solution turned brown immediately upon addition of HCl but, much to
his initial puzzlement, the resulting hematin did not extract into the
ether layer.
Explain in chemical terms why HCl cannot be substituted for glacial acetic acid in
this experiment. Draw chemical structures and diagrams to support your
argument. If you are uncertain of the explanation, please outline the
possibilities you have considered or how you analyzed the problem.
Conceptual Representation of the Stokes (1864) Article
Reducing
Agents
+H2CO3
O2
+ O2
Reversible
Scarlet Cruorine
Acid, Heat,
Organic
Solvents
Purple Cruorine
Irreversible Decomposition
Acid, Heat,
Organic
Solvents
Albuminous Precipitate
Reducing Agents
Brown Hematin
O2
Red Hematin
Oxidized
Products
Irreversible
H2O
Conceptual
model for the
reactions of
“cruorine”
described by
Stokes. The
color of the
squares
corresponds to
the spectral
properties of
the compound
involved.
Reversible “Reduction” of
Oxyhemoglobin
Add a small amount of
sodium dithionite,
Na2S2O4
Stir in the presence of air
Constructing Models
to Explain Observations
O2 (g)
1. Diffusion, very slow transfer
Air
2. Shaking, rapid transfer
Water
slow
O2 (l)
HbO2
rapid
Reversible binding
SnIV
Hb SnII
Irreversible oxidation
H2O
Introduction to Biochemistry
Student Assignments
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Write an Abstract
Construct a Concept Map
Draw an Appropriate Illustration
Critique from a Modern Perspective
Find out about the Author
Explore a Cited Reference
Contains
BLOOD
Contains
Plasma
Which
includes
Clotting
Factors
Red Blood Cells
BLOOD TRANSPORT
OF OXYGEN
CHEMISTRY
Lyse in water
to release
Oxygen
In lungs
OXYGENATION AND DEOXYGENATION
Oxyhemoglobin
(Scarlet Cruorine)
Arterial
Blood
Deoxyhemoglobin
(Purple Cruorine)
Venous
Blood
In tissues
Reversible dissociation
Oxygen
Such
as
H2CO3
Fibrinogen
Has a
distinctive
Absorption
Spectra
Observable
with a
Spectroscope
Protein
Precipitate
Heme
Spontaneously reacts
with oxygen forming
Brown
Hematin
Soluble in
Reducing
Agents
H2O
irreversible
slow
SnII
Acid
Ether
fast
FeII
Oxidized
Products
SnIV
Reduced
Carbon
(Food)
Carbon
Dioxide
CELLULAR RESPIRATION
BIOLOGY
FeIII
Stabilized by
2H+
Anionic
Hematin
In tissues
O2
Heat, Acid, Ethanol
decomposition to form
Colored Compound
Water
Soluble in
Aqueous
Base
Tartaric Acid
Indigo
HEMATIN FORMATION
AND SEPARATION
Colorless
Product
OXIDATION AND Oxygen
REDUCTION REACTIONS
Concept map
illustrating the
relationships
among significant
words and ideas in
Stokes’ 1864 article.
Group Quizzes
with IFAT® Answer Sheets
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Multiple Choice Format
Lottery Ticket Design
Immediate Feedback
Partial Credit
Tremendous Discussion Stimulator
Students Like It
Potential for Multiple Use
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http://www.epsteineducation.com/
BAMBED 33, 261-2 (2005)
Allison, A. C., (1954) Brit. Med. J. 1, 290-294
Protection Afforded by Sickle-Cell Trait Against
Subtertian Malarial Infection.
Question for group consideration and
subsequent class discussion:
How might you demonstrate that people
carrying one allele for sickle cell hemoglobin
have increased resistance to malaria?
Introduction to Biochemistry
Student Perceptions 1995-2004
A. Consider items 1 through 12 and rate them with respect to how important
they are for success in CHEM-342, Introduction to Biochemistry.
(1 = Extremely Important to 5 = Not Important; N = 263 out of 268)
Item
1. Personal Initiative
2. Library Research
Skills
3. Taking Notes in Class
4. Writing Skills
5. Collaboration with
Classmates
6. Oral Communication
Skills
Mean
± SD
1.47
± 0.61
1.88
± 0.80
2.92
± 1.00
2.16
± 0.85
1.55
± 0.76
1.77
± 0.81
Item
7. Prior Knowledge
8. Memorization
9. Learning New
Information
10. Problem Solving
Skills
11. Conceptualization
12. Attendance
Mean
± SD
2.83
± 0.97
3.90
± 0.95
1.61
± 0.77
1.64
± 0.79
1.50
± 0.65
1.43
± 0.69
Introduction to Biochemistry
Student Perceptions 1995-2004
B. Consider the items 1 through 12 in relation to other science courses.
Circle those items which, in your experience, are more important in CHEM-342
than in most other science courses you have taken. (N=263)
Item
Percent
Item
Percent
1. Personal Initiative
40.8
7. Prior Knowledge
12.1
2. Library Research
Skills
3. Taking Notes in
Class
4. Writing Skills
60.0
8. Memorization
1.1
1.9
9. Learning
New Information
10. Problem Solving
Skills
14.8
5. Collaboration with
Classmates
6. Oral Communication
Skills
72.7
11. Conceptualization
40.5
57.8
12. Attendance
39.7
37.5
46.9
Effect of Facilitators on Attendance
Attendance before facilitators: 91.1%
Attendance after facilitators: 94.1%
(32% reduction in absences)
Allen & White (2001). In, Student-Assisted Teaching,
Miller, Groccia & Miller, Eds. Bolton, MA: Anchor.
Effect of Facilitators on Effort
Hours before facilitators: 4.8 per week
Hours after facilitators: 6.0 per week
(25% increase in time spent on course
work outside of class)
Allen & White (2001). In, Student-Assisted Teaching,
Miller, Groccia & Miller, Eds. Bolton, MA: Anchor.
Performance Comparison on 21-item Pre-post Test
on Chemistry Concepts Important in Biochemistry
Spring 2012
15
Post > Pre test
12
9
Pre > Post test
6
Ave 9.60 → 12.92
Post-course Tes Score
Post course Test Score
18
3
Fall 2010
21
21
18
Post > Pre test
15
12
9
Pre > Post test
6
3
Ave 10.98 → 12.23
0
0
0
3
6
9
12
15
18
21
0
3
6
9
12
15
18
21
Pre course Test Score
Pre-course Test Score
Sophomore PBL Course
Upper-Level Lecture Survey
CURE Survey Results
Course Elements Gains
CHEM-342 Students
All Others
Course Web-Site
Introduction to Biochemistry
www.udel.edu/chem/white/CHEM342.html