Biochemical
Education
ELSEVIER
Biochemical Education 26 (1998) 281-285
Laboratory practical work as a technological process
Augusto Pich-Otero, Sara Molina-Ortiz, Laura Delaplace, Oscar Castellani,
Daniela Hozbor, Delia Sorgentini, Anl'bal Lodeiro
Area de Quhnica BiohJgica y Biologia Moleculal: Facultad de Ciencias Exucla.s. U, iverskhul Nacicmal de La Plata. La Plata. AI74enthut
Abstract
Laboratory practical work is commonly intercalated with theoretical and seminar classes in packages that cover single units of a
given course program. Emphasis is put in to illustrate important theoretical concepts and in to improve students" laboratory handling
skills. Wc observed that this inw~lvcs serious disadvantages, namely (i) students lack an integrated view of the subjects, (ii) time
constraints for each experimental session preclude students to become familiar with most of the techniques and approaches, Off) how
to manipulate laboratory equipment become more important than the objectives and rational explanation of results, (iv) work
planning and evaluation of reproducibility of methods are not considered, (v) elaboration and communication of results are not
encouraged. To overcome these limitations we developed a new schedule were students get problem-based learning of theoretical
concepts during the first half of the course and plan and execute a laboratory project during the second half. The project is performed
within one of three main areas: purification, enzyme kinetics or metabolism~molecular genetics, with/]-galactosidase as model system.
By inducing a more positive attitude in the students towards the practical laboratory work, this schcdulc allowed us to awfid the
mentioned disadvantages while keeping the traditional practical laboratory work objectives met. © 1998 IUBMB. Published by
Elsevier Science Ltd. All rights reserved.
1. Introduction
Traditionally, practical laboratory work has been a
valuable method for demonstrating to students some of
the concepts dealt with in lectures. In such laboratory
classes, students are asked to follow a number of established recipes and protocols in order to attain a predetermined objective. Through the correct application of
techniques, the experimental data obtained should fit
with the predicted results and this is the main objective
of each experimental session. The experimental observations are then used to revisit the theoretical concepts,
from a point of view that now provides new insights
based on real world situations. In addition, it is thought
that this kind of organization of the course teaches
students about the use of experimental methods and
gives them the opportunity of improving their laboratory
skills.
The rapid global improvement and increasing acccssibility of technology requires that universities should
produce independent and self-critical graduates who
should be able to develop, carry out and control industrial processes by themselves, and who can take advantage of all available tools. In developing countries such as
Argentina, it is essential that new professionals arc able
to understand and rapidly adapt to new technologies as
they arise, as well as developing technologies by
themselves as required for specific problems. Thcrefi)re,
they should be able to learn.[or t h e m s e l v e s how to develop
and implement completely new processes, and participate in close interactions with other professionals inside
and outside the country and/or the company. The
development of these kinds of skills are not addressed by
traditional lecture/laboratory teaching programmes, thus
it is left to the future professionals to acquire these skills
themselves.
In fact, these abilities are not very well acquired from
textbooks or lectures; instead, they involve a very
important element of reasoning and expertise, and the
development of critical skills that only constant and
focused practice can help to achieve. The authors are
engaged in teaching biological chemistry to undergraduates in their fourth year of pharmacy training at the
Faculty of Exact Sciences, National University of La
Plata, Argentina. Since 1996 we have been setting up a
new teaching strategy to get the students involved in
practical laboratory work as a technological process, with
the aim of providing adequate stimuli to develop the
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282
A. Pich-Otero et al./Bh~chemical Education 26 (1998) 281-285
above-mentioned skills, in this way, laboratory work has
been converted from "one more step in the course" to a
major challenge that the students take responsibility for.
Therefore, the responsibility for the way in which experimental work is conducted is shifted from the instructors
to the students, and this constitutes the main motivation
to carry out enough practical work (with mind and
hands) to adequately develop the above-mentioned
reasoning, expertise and critical skills.
2. Previous history of our laboratory practical work:
W h y did we decide to make a change?
Up to 1996 we taught a traditional biological chemistry
course. For each subject the students had lecture
sessions complemented by problem-solving classes or
seminars, followed by practical laboratory work that was
done in the traditional way. The course was divided into
four modules by subject (i.e. Structure and purification
of macromoleculcs, Enzyme kinetics, Metabolism, and
Molecular genctics), and each subject contained a
complete set of lectures, seminars and lab work. Consequently, each modulc was essentially autonomous, and
provided little incentive for the students to try to
integrate the different subjects as needed in the real
world (for example, enzymes are macromolecules that
can be purified, which might have function in metabolism, and are coded by genes that can be cloned).
In practice, we have observed that the "autonomous"
laboratory sessions generate many more problems than
simply hindering the acquisition of an integrated view of
reality. An important aspect concerns objectives. As
mentioned, the instructor's objective is that the students
should obtain good experimental data. However, "good
experimental data" are often thought as a precise
"match" of a given observed set of results with the
expected set. For example: "was the Lowry calibration
curve good?"; "did we get values for the protein samples
according to the dilutions made'?"; "could we observe the
expected bands in the agarose gel after the miniprcp?"
- - and so on, become the most important questions, as if
the only objective were to assess the manipulative skills
of students. The students tend to be shifted from one
method to another with the additional requirement of
finishing within the time limits of each lab session, thus
leaving them with few opportunities to get sufficient
practical expertise to understand what are they doing
and why. Lack of this expertise is frequently raised as the
explanation for the lack of match between the results
obtained by the students and the expected ones. Both the
lack of understanding, and the permanent feeling that
they do not know how to work properly, disappoints the
students - - thus leading to an inappropriate objective on
their part, namely just to finish the lab session and go
home.
3. The new m e t h o d o l o g y
We changed our schedule in order to make room for
extended experimental sessions where students could get
involved in technological processes that more closely
resemble the true situation of most professional work in
pharmaceutical industry, biotechnology, biochemical
research and related areas. In the first of the two semesters, the students have lectures and seminars that use
problem-based learning methodology [1] that relates to
the four main subjects mentioned above. At the end of
this first semester, the students get an evaluation during
which they have to try to solve real problems (mostly
borrowed from recent research articles) that integrate
the subjects and where the handling of concepts is much
more important than their memorization (to strengthen
this bias, students are allowed to use books during the
test). Those who pass the test may continue in the second
semester with the modified practical laboratory work.
In Fig. 1 we outline the steps commonly followed in a
technological process. This starts with the identification
of the problem, which also has to bc put in context, i.e.
viewed as part of a more general situation where we need
a better understanding and/or a new practical output.
Next, a project must be elaborated by which it is expected
to obtain solution(s) to the problem by means of the
proper application of techniques in relation to the availability of human and material resources. Once the
ldentificate and
put the problem
f
Selectthe proper
techniques to
- ""---~~elop
the pro!eel ..__.....-- ~
II
~valuate
t h e ~
uman and material .../)
esources
~
"
"......
.
processand its results
..~
Fig. I. Schemeof a technological process describing its principal
steps. Arrowheads are used as in flow charts: -,, stimulation; --I,
inhibition.
A. Pich-Otero et aL/Biochemical Education 26 (1998) 281-285
project is delineated, its execution by means of available
technological means is evaluated. This process may
dictate a re-elaboration of the project, an adjustment of
its goals, or even its interruption, if it is revealed to be an
impossible task. If the project continues, its operation
and the results produced must be evaluated; this evaluation can modify the way in which the project is executed
(or recommend its interruption) and also perhaps modify
our understanding of the problem (or reveal that it was
misunderstood, and that such a problem did not exist in
the way that had been thought).
Given that the most important priorities of the "traditional" lab session were to teach experimental
techniques, we asked ourselves which techniques were
involved. We decided that two classes of techniques were
used. One of these, which we will call the general class,
required neither intensive use of equipment nor expensive reagents, and therefore could be carried out by all
the students in almost all the experimental sessions.
These included chemical and enzymatic reactions that
measure reaction products by colorimetric methods in
three out of the four experimental sessions, and fractionation of different materials by centrifugation in all the
four labs. The second, which we will call the specialized
class of techniques, included those that made intensive
use of relatively expensive equipment and therefore the
number of students involved was limited by the availability of equipment. Examples were electrophoresis of
DNA and proteins, and chromatography by gel filtration
and ion exchange. In these cases only three or four
students could work actively, while the others were just
required to observe. To design objectives for the students
without simultaneously losing the goals of the traditional
laboratory schedule, we used/~-galactosidase as a model
system able to cover the main subjects treated in our
course. This enzyme can be purified by classical methods
[2], its biological activity can be measured by a one-step
colorimetric reaction by both in vitro [3] and in vivo [4]
methods, values for its kinetic parameters and activation
energy are available in the literature [5], it participates in
carbon metabolism and provides glucose for anabolism
or catabolism depending on the cell energy charge [6],
the gene cncoding this enzyme in Escherichia coli has
been cloned and fully characterized [7-9], its expression
and transcriptional regulation includes catabolite repression [ 10,11 ], and there are plenty of wild-type and mutant
strains available, as well as plasmids that carry the lacZ
structural gene under the control of diverse promoters
[12].
In the new schedule we divide the students into three
groups (5-10 per group). Each group engages in one
activity that they will carry out under supervision of one
instructor. The definition of the objectives for each
activity is accomplished in two previous seminars among
the students and the instructor, and the students arc
asked to agree their objectives during the semester. The
283
required output is a scientifically explainable result, i.e. a
general and reproducible one. As they progress with
their respective projects, they must communicate their
results both orally to the instructors and to the other
students at lab seminars held periodically, and finally, by
a written report. The activities suggested by each group
in 1997 are given in Fig. 2. Here we observe that all three
activities inw)lvc the use of the general class of techniques
whereas when the specialized class of techniques was
used by three or four students of one group, the others
(including other groups) were called upon to observe and
provide an explanation, as was done before in the "traditional" laboratory work schedule. Since the model
system is common, no significant losses of understanding
of techniques are perceived.
In the development of the technological process, the
students prepare their work plans during the first
seminar and, guided by an instructor, they consider the
possibilities and think about the equipment they need for
the project. In the second seminar, the plans and protocols written by the students are discussed and alterations
made when necessary. During the next three lab sessions,
the students carry out the work plans already agreed.
After these three lab sessions they describe the preliminary results they have obtained as an oral presentation.
In this forum the results are evaluated and future activities toward achieving the research objective are discussed with the participation of the other students and
the instructors. After this seminar, all groups have
another three classes of experimental work and another
scminar in the same format. By the last two lab sessions
it is expected that the main objectives will already have
been met, and so the time may be devoted to collaborative work in which different groups exchange materials
and expertise in order to generate new information of
mutual interest (this activity is again favoured by the
work done with a common model system). Finally, they
produce a written report and make the final oral presentation, both of which form the core of the second evaluation of students performance.
Using the scheme described here we have observed
that the students became much more interested in the
projects, since (1) having the whole semester to complete
the work they have sufficient time to become familiar
with the lab techniques and so gradually shift their attention to what they were doing and why instead of how it
should be done, and (2) their success or failure rests in
their own hands instead of those of the instructors from
the beginning of the second semester, and so lack of
results can no longer be explained simply by claiming
"lack of expertise". Having both an increased responsibility for the attainment of the experimental objectives
proposed by themselves, and the feeling of challenge that
accompanied this partial transfer of laboratory work
management, students develop a better motivation to
working in the lab. By comparison with the "traditional"
284
A. Pich-Otero et aL/Biochemi<'al Education 26 (1998) 281-285
schedule we found that students did not acquire fewer
technical skills but gained the capacity to: (i) plan their
own projects, (ii) properly execute and evaluate the
results by themselves, (iii) understand the logic and goal
of every step, and (iv) communicate their observations
and interpretations both orally and in written expositions. [To get a clearer picture of the whole sequence of
laboratory work and the standards of communication
achieved, selected students' laboratory work reports (in
Spanish) are available on request from author: E-mail
address: lodeiro~rnahuel.biol.unlp.edu.ar.]
Encouraging the students to develop these capacities
in order to obtain from them a positive attitude to
laboratory learning was a major contribution to our new
laboratory work schedule. In 1997 we surveyed students'
opinion at the end of the course in order to determine
their evaluation of several aspects of the practical work.
This questionnaire was obligatory for all the students and
was anonymous, it was carried out in class but on an
individual basis and in the absence of the instructors: the
marked questionnaires were collected up by a student.
Making the questionnaire both obligatory and anonymously was important for ensuring that all the opinions
- - both favourable and unfavourable - - were recorded.
The results are summarized in Table 1. Although wc
have no comparative results for the years when we only
had a "traditional" laboratory work schedule, it can bc
appreciated that students, in general, were positive about
the new laboratory work schedule (all the items that
asked for comments about improvement of the students'
skills received more than 70% scores). In particular, they
considered that the new style laboratory work contributed to an important improvement in their manual
skills (87%) and to their ability to analyse experimental
data (79%). The exercise of preparing a written report
was considered to be very useful to encourage them to
express ideas, organize information and to process and
communicate experimental data (82%, 82% and 84%,
respectively), this being the first written report of this
type t h a t students had prepared in their whole careers.
Not so highly rated, but still above 70%, were the assessments of the contribution towards improving their selfevaluation and planning abilities (72% and 74%,
respectively), and the contribution to the understanding
of the subject of biological chemistry (76%). The lowest
score was for the c o n t r i b u t i o n made by the written report
to literature search (70%). This task was carried out
mainly using the databases available on the Internet,
since the faculty's library is very poorly supplied with
journals because of budget limitation. Nevertheless, the
ACHVITY 1
Purification
ACTIVITY 2
Kinetic Study
Escherichia coli
Determination of
initial rates
crude extract
1
Precipitation with
(NH4)2SO4 40%
Calculation of Kinetic
Parameters: Km and Vmax
Chromatography:
Ion Exchange
Gel Filtration
Temperature effects [
in enzyme activity
Process evaluation
by quantitative
analysis and
SDS-PAGE
Calculation of
Activation Energy
ACTIVITY 3
Metabolic Study
Transformation of I
into lac +
E. coli lac
Phenotypic and Genotypic
Analysis
Glycogen Biosynthesis
from glucose or
lactose in E. coli lac +
and/ms- strains6
Fig. 2. Activities carried out by three laboratory groups (around 5-10 students each) as technological processes during the 1997 course.
Reproducible results, communicatedboth orally and in a written report, were required in order to pass the course.
285
A. Pich-Otero et al./Biochemical Education 26 (1998) 281-285
Table 1
Questionnaire on' the practical laboratory work carried out in the 1997 course. The items are scored from I to 5, given as mean value _+SD for each
item (answered by 5(1 students)
Mean score +_SD
Question
Contribution of the practical laboratory work to the improvement of your:
(il) Manual skills for working in the laboratory
(i2) Ability in analyzing experimental data
(i3) Ability of self-evaluation
(i4) Planning ability
(i5) Understanding of biological chemistry (as a whole)
(ii) The written report of the laboratory work enhanced your ability to:
0il) Order and express ideas
(ii2) Organize information
(ii3) Search bibliography
(ii4) Process and communicate experimental data
(iii) Doing experimental work in a single subject limited your understanding of the other subjects*
(i)
4.34 + 0.86
3.94 __+_0.73
3.62_+0.83
3.68 _+0.73
3.78_+0.76
4.12_+0.89
4.10+_1).85
3.52 _+ 1.1/(t
4.18_+0.82
3.05 _+ 1.115
*Scored from 1 = very little to 5 = severely
literature search was also impaired by the limited availability of computers connected to the lnternet and the
disparate level of the students' English (which might
explain the high standard deviation of the scores in this
question). Another question of interest was related to
the students' opinion about how performing experimental work in a single subject (dictated by the project)
impaired their understanding of other subjects that were
being taken by the rest of students. Answers were around
the middle score range and had the highest standard
deviation, which suggests that whereas an important
fraction of students believed that working in a single
subject limited their understanding of the other subjects,
another equally important fraction did not.
An independent opinion poll was run by the Students
Center of the Faculty of Exact Sciences (CEFCE) at the
National University of La Plata. This was directed more
towards evaluating professors' and instructors' performance than the laboratory work itself, but some of answers
reinforce the above conclusions. Beyond the general
good ratings received by profcssors and instructors, 60%
of 40 students considered the evaluation system "very
good", 22% considered it "good" and 15% "excellent";
only 2.5% considered it "bad". On the other hand, when
asked about a given set of changes that should be introduced to improve the course, only one student among 19
considered that "seminars and practical work should be
intercalated", i.e. go back to the "traditional" experimental work schedule. A higher proportion asked for
"more time for seminars" (8 out of 19) and "smaller
groups in the lab and more availability of equipment" (10
out of 19). None of these 19 students considered it was
necessary to "avoid giving so much compressed information", nor "reducing the number of people working at
one time in the laboratory".
Taken together, these results suggest that students
perceived this exercise as useful and interesting.
Additional evidence for this conclusion comes from the
observation that in 1996 two out of 40 and in 1997 five
out of 50 students that finished our course then asked for
places to work as assistants on our research projects, in
remarkable contrast to only one student that did the
same from 1991 to 1995.
Acknowledgements
The authors are grateful to Professor Edgardo Donati
for critical reading of the manuscript.
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