more student-active learning in my upper-level cell physiology course, I
redesigned the laboratory component of the course to include
experiments to be performed by the class as a whole. Small groups of
cooperatively designed original experiments and led the class in performing
exercises. To help the students
make necessary decisions and choices, I provided them with some parameters
their experiments. I advised
that the experiments should elucidate some aspect of cell biology, use a
methodology or equipment available in our department, be performed in a
laboratory period, and be designed and presented by a group of three to four
composed of 15 undergraduate students in their senior year.
There were seven Sports Biology majors, three Biology majors, and one
Chemistry/Biology major. There
four self-selected groups.
students had all taken at least one laboratory course per semester
their college career.
twelve laboratory periods scheduled during the semester.
The first eight periods were spent in a traditional laboratory
Students were given written introductory material containing
background information, technical procedures to be followed, and questions
answered after completing the exercise. These
exercises were planned to illustrate concepts that had been discussed in
and to familiarize students with various laboratory techniques used in cell
biology. Weekly exercises were chosen to provide students hands-on
experience with a relatively large selection of methods from which to choose
their own experiments. The last
four weeks of the semester were devoted to the presentation of
experiments (one per week).
final month of the course, students had practiced protein gel
enzymatic assays using spectrophotometry, cellular fractionation using
differential centrifugation, isolation of red blood cells, separation of
water-soluble and lipid cellular components, phospholipid separation using
layer chromatography, quantification of phospholipids based on the
of a standard concentration curve, and the measurement of aerobic metabolism
time was devoted to planning and preparation for the experiments.
Early in the semester the class compiled a list of characteristics of
good experimental design. They
decided that a good lab exercise should:
1. Be easy to follow
2. Have a definite result
3. Have the preparatory work completed in
4. Allow some room for error
5. Be able to be completed within the allotted
of a laboratory period
6. Be based on background information provided
period was spent examining a variety of laboratory manuals (from
biology courses and cell/molecular biology courses) to seek feasible
applicable background information, preparatory instructions, etc.
A subsequent lecture period was spent
perusing chemical catalogs for the necessary supplies in appropriate
amounts at affordable prices. Supplies were ordered based on the students’
calculations and recommendations.
a later lecture period the groups met and discussed their preliminary
asking for guidance as needed.
group home-work assignment they wrote the laboratory hand-out for their
exercise. They handed in a
draft of their experiment about a month before the student
The drafts were returned to the groups with suggestions for
The students were responsible for testing and revising their
protocol before they presented it to the class.
In order to test their experimental design they first prepared
(based on their own calculations) and set up equipment (including cleaning
sufficient glassware for the entire class).
Some of the experiments required more complicated advance preparation
like isolating particular cell fractions to be used later by the class.
groups spent additional time in the lab preparing their material. The final draft of their laboratory hand-out was due one
before their presentation to allow time for the campus print shop to make
periods devoted to planning the experiments were interspersed with more
traditional lectures during the first eight weeks of the semester.
Throughout the course lecture topics included basic chemistry of
biological molecules, intracellular protein sorting and transport, cellular
metabolism, the cytoskeleton and cell movement, the plasma membrane and
molecular transport, endocytosis, and the extracellular matrix.
student groups designed their experiments using their earlier experience
cellular fractionation, enzymatic assays, and the measurement of metabolic
and their knowledge of protein structure, factors that effect enzymatic
activity, lipid biochemistry, and the structure and function of lysosomes
mitochondria. The four original
student-designed experiments were:
1. “Quantification of Mitochondrial Levels in
Cardiac and Skeletal Muscles”, a marker enzyme assay (succinate
used to compare mitochondrial abundance in white skeletal muscle, red
muscle, and cardiac muscle (all dissected from chicken).
2. “The Effects of Caffeine on Mouse
Metabolism”, an investigation of caffeine as a metabolic stimulant in
3. “The Breakdown of Triglycerides”, an
investigation of lysosomal lipase from chicken liver.
4. “A Study of Hemoglobin and Iron”, an
investigation of changes that occur when defibrinated blood is stored longer
than its shelf-life.
the laboratory portion of the course was based on three quizzes and the
presentation of their own experiment to the class.
The quizzes covered their understanding of all of the laboratory
exercises performed during the semester including the student-led
experiments. Each component was worth 25 % of their grade.
conclusion of the course I asked for feedback regarding this
All responses were positive.
from some selected responses follow:
was fun to see each other’s preference in subject and this added to a
diversity in lab.”
has given me the experience of designing an experiment, testing it, and
up a protocol. It requires me to think about what it is that I am doing, as
opposed to just doing it.”
made us think about aspects of experiments that we never really do.”
is a lot of work preparing solutions, ordering materials, designing and
the lab and then presenting it.”
and performing an experiment makes each student who created it highly
responsible... Because so much time was involved, results mean so much
felt that designing a lab experiment allowed me to experience what research
would be like. It was good for watching a thought develop from beginning to
finding an answer.”
tend to learn more from this type of experience.”
gives the students a chance to teach something they want to do.”
confirmed that I never want to teach, but now I can appreciate or
understand more about what it takes to do a lab in class.”
helped bring together a lot of the class experiences I have had in this
this activity has provided an informal “capstone experience” for the senior
science majors in this cell physiology class. The level of student
was extremely high. Many of the
student responses encouraged me to continue with this exercise while
more time for the planning and preparation stage.