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Some thoughts on problem-based learning
202
Features Section: Problem-based Learning Editor: C A S m i t h , the M a n c h e s t e r M e t r o p o l i t a n U n i v e r s i t y , U K
It will have been apparent that the Problem-based Learning Page in the last issue of Biochemical Education went somewhat awry. Unfortunately the article by Professor Campbell was transposed with a general review of problem-based learning by myself et al! 1 We apologise for the error. The Problem-based Learning Page in this issue therefore has two articles: one by Professor Campbell, the other by Drs Welch and Carroll. To reiterate the last issue, the article by Professor Campbell is different from anything other submission which the Page has published previously. It does, however, make a number of points pertinent to Biochemical teaching/education which most would think justified and many would own up to at least some of the criticisms. Professor Campbell is critical of a number of aspects of PBL and supports his views by stating that there have been a number of reports critical of PBL, for example Berkson (1993). 2 However, Berkson 2 is not by any means solely critical and sees a number of merits in PBL. Professor Campbell then develops his paper to outline an underlying rationale for a 'basic' Biochemistry syllabus and lists those topics which he feels should be covered in a lecture programme. Professor Campbell's submission contains much material to ponder on, and Biochemical Education, and the PBL Page in particular, would be delighted to receive letters and views on the topics he has raised. The article submitted by Drs Welch and Carroll is an excellent example of the practical use of PBL and I commend it to you. As always, the Problem-based Learning Page welcomes ideas and suggestions on the teaching and assessment of biochemistry and related disciplines. References 1Smith, C A, Powell, S C and Wood, E J (1995) Developing problemsolving skills in students: an esential corollary to problem-based learning in biochemistry and related disciplines. Biochem Educ 23, 149-152 2Berkson, L (1993) Problem-based Learning: have the expectations been met? Academic Medicine 10, $79-$88
B I O C H E M I C A L E D U C A T I O N 23(4) 1995
0307-4412(95)00076-3
Some Thoughts on Problem-based Learning PETER N CAMPBELL University College L o n d o n Gower Street L o n d o n W C 1 E 6BT, UK
Introduction Every year since I began teaching medical students in 1946, I have heard calls for changes in the undergraduate medical curriculum. These have come from a number of different directions, sometimes because of a change of Dean, sometimes because it is necessary to introduce new subjects, and sometimes because of complaints that the course is overloaded with facts. As readers of this journal will know j the latest call is from the General Medical Council which has issued a report entitled "Tomorrow's Doctors". 2 This Report recommends that there should be a core curriculum to which options can be added. It also demands a substantial reduction in the amount of factual material that students are expected to assimilate and places more emphasis on problem-based learning (PBL). I have been impressed in my visits to medical schools in various countries by the extent to which the PBL system has been so readily adopted by those in authority considering that there have been a number of critical reports among the many which have advocated PBL (see for eample Berkson3). Role of facilitators It is interesting that in the U K there is an increasingly strong feeling against PBL which has even been used in primary schools. I quote from The Times of 28th January 1995: "Teachers were instructed to present themselves as facilitators - - there simply to guide the children's own processes of discovery - - rather than as sources of expertise. The most pejorative word in the education lexicon became 'didactic'. Teachers were not to instruct - they were simply to supervise the child's quest for knowledge." This may be an extreme view of PBL but ! have certainly detected elements of it in the application of P B L to the education of medical students. The initial enthusiasm for PBL came from medical schools in Canada and the USA where the education of medical students is largely a postgraduate activity. In this respect such medical schools are almost unique in the world, for in virtually all other countries the medical
203 course starts with entry from school at about 18 years of a g e . The report by Berkson 3 concludes that P B L has much merit provided that the class size in toto is small, eg not m o r e than 40. Even then it has disadvantages in that it is usually not possible to find enough expert teachers, so that those who guide the P B L sessions are what is termed ' n o n - e x p e r t ' . As I have mentioned, those who favour P B L do not mind this, for the facilitators are not there to provide 'mini-lectures' but to guide the discussion in a fruitful manner. T h e r e are other requirements for success, such as the provision of numerous tutorial rooms, since the teaching groups should not be larger than about 10 students. T h e r e is also the need for well-equipped library resources.
Background knowledge My experience suggests that those who adopt P B L need to think carefully about the factual material - - the vocabulary - - with which the students need to be equipped at the start, for one cannot have a fruitful discussion without some facts. In the past, biochemists have often been accused of donning the mantle of the new anatomists in that they have d e m a n d e d from the students memorisation of a large body of facts soon to be forgotten. Often I have felt that such criticism had some justification. In serving as an External E x a m i n e r I have found myself protecting the student from teachers who were seeking the regurgitation of facts e x p o u n d e d in a particular lecture. A recent experience as External Examiner showed the dangers of applying P B L to students with very little factual background and of then asking them multiple-choice questions calling for factual minutae. The result was that the students failed not only on the recall of factual knowledge but also showed little ability to handle problems. This is also a conclusion reached by Berkson. 3 It seems to me inevitable that the undergraduate medical curriculum will have to be slimmed down and at least some P B L introduced. Thus the biochemists will have to decide what it is they wish to transmit to the students in terms of facts in perhaps 30 lectures. However, before giving my opinion of what the core might contain I would like to state my position concerning the perennial argument between 'vocational training' and 'university education'.
Education versus vocational training In the U K it would be fair to say that until recently we had two kinds of medical schools. Those that were part of a multifaculty university and those (mostly in London) that stood alone, being closely allied to a hospital. For some time various reports have argued against the stand-alone schools on the grounds that the medical students should have the opportunity to experience a broadly-based education in their preclinical years. This is very much in line with the training of other professions such as law and accountancy which have m o v e d towards the acquisition of a university degree before the vocational training. It seems to me right that medical doctors should have a broadly-
B I O C H E M I C A L E D U C A T I O N 23(4) 1995
based education not only on general grounds but also because they should be equipped to maintain their interest and knowledge of their profession for the 40 years they might expect to practice. As biochemists we have been fortunate in that we can now apply sound scientific principles to an understanding of the metabolism of both normal and pathological states. Thus I feel we can try to steer a middle course between education in depth and vocational training. The crucial question is to ask always why one is teaching a particular subject. If the answer m a k e s no sense on either educational or vocational grounds then it should be stopped.
Chemical background An immediate concern for a biochemist is the extent to which a knowledge of chemistry is required for entrants to the course. In the U K , where the different medical schools have authority over the admission of students, there has been much variation in the qualifications d e m a n d e d , but a c o m m o n requirement has been a good standard in chemistry form high school. There is now some relaxation in this respect and it is certainly interesting that in m a n y countries, such as G e r m a n y , there are no d e m a n d s for a demonstrated knowledge of chemistry, or indeed of any other science subject. While we can certainly overdo our emphasis on rote learning of chemical formulae so that the biochemistry course comes to be seen by the students to be dominated by the Krebs Cycle, or the structure of the ketone bodies, we are surely right in expecting an understanding of the meaning of chemical formulae in terms of structure and an appreciation of the characteristic properties of carboxylic acids, amino acids, lipids and carbohydrates, etc. The basic concepts of inorganic and physical chemistry are also essential. (My concern is to avoid the necessity of failing a student who has no m o r e ability to c o m p r e h e n d a chemical formula than I have to read Chinese.)
General principles At the start of a course it would be good to emphasise some general principles overriding the biochemical events in all types of living cells. I was always attracted by the first chapters of the various editions of Lehninger's text books. H e started by stating that the challenge to the biochemist was to explain how it is that living things are c o m p o s e d of lifeless molecules. The two most characteristic properties of living organisms is their ability to extract and transform energy from their environment and their ability to reproduce themselves, ie their capacity for precise self-replication. H e went on to explain that the chemicals involved are similar in all living things, that the energy currency is always ATP, and that the transmission of genetic information is always through nucleic acids. The function of enzymes which catalyse metabolic reactions at amazing speed and with practically no byproducts is crucial. A n o t h e r feature is the versatility of the chemicals involved, such as the amino acids which not only serve as building blocks for the proteins but also are
204 important in metabolism, and the same applies to the nucleotides. In terms of the economical use of energy, Lehninger indicated that there was careful conservation, although I am not too sure if this is really true in view of the loss of expensively constructed macromolecules during the maturation of nucleic acids and proteins for example. Living cells can be rather profligate in terms of energy. The metabolic turnover of the body constituents may also appear to be wasteful of energy but is in fact a good way to control metabolism, ensure that there are no pile-ups and that there are no useless molecules in the cell. The advantages of confining the different areas of metabolism within membranous organelles should be described as well as the corollary that proteins need to be targeted to the various organelles. Finally, and most importantly, the concept of structural complementarity needs to be emphasized whereby small molecules 'fit into' macromolecules as in enzyme action, signalling by means of membrane bound receptors and antigens interacting with antibodies. This complementarity is also important in ensuring that no molecules of DNA are synthesized without a DNA template.
Core material The lectures or didactic presentations might cover the following topics: (1) Types of cell, prokaryotes, eukaryotes, viruses, organelles, (2) Structure of amino acids and proteins, (3) Structure and function of enzymes (4) Nucleic acids (5) Protein synthesis (6) Recombinant DNA (7) Molecular cell biology (8) Carbohydrate chemistry (9) Nitrogen metabolism (10) Lipid structure (11) Carbohydrate metabolism (12) Lipid metabolism (13) Oxidative phosphorylation (14) Interrelationship between carbohydrate and lipid metabolism (15) Diabetes, (16) Membrane structure and function, (17) The structure and function of vitamins (review). However, some of this material might be assigned to students to learn and understand by 'selfinstruction', the 'lectures' being used for highlighting key areas and interconnections. In the above list, which as I have previously indicated could take about 30 hours, I have particularly avoided examples of the application of biochemistry to the aetiology of specific diseases, except diabetes mellitus, since these would form the basis of subsequent problem sessions. I include diabetes since the interrelationship between carbohydrate and lipid metabolism is at the heart of metabolism. References i Higgins, S J (1994) All Change in Britain's Medical Schools, Biochemical Education 22, 66-69 2Tomorrow's Doctors, Recommendations on undergraduate medical education, December 1993, published by the General Medical Council, 44 Hallam Street, London WIN 6AE, UK 3Berkson, L (1993) Problem-biased Learning: Have the expectations been met? Academic Medicine 10, $79-$88
BIOCHEMICAL EDUCATION 23(4) 1995
0307-4412(95)00113-1
A New Erythrocyte Enzyme Polymorphism? SIMON G WELCH and MARK CARROLL
Biochemistry Department Queen Mary & Wesrfield College (University of London) London E1 4NS, UK Introduction The curriculum followed by medical and dental students at Queen Mary & Westfield College emphasises several aspects of independent learning, including a problembased approach.l Within a programme of student-directed learning, course organisers incorporate clinically orientated case-studies in which students are asked to address the underlying principles by means of a series of questions. Their answers are discussed with a tutor at a subsequent tutorial. Solving a clinical biochemical problem thus gives the students some feedback on their understanding of the course material, and also emphasises to them the medical relevance of the subject. In our experience, it is not easy to find problems with a suitable content and at an approriate level of difficulty. Most modern textbooks of biochemistry include some questions of a problem-solving nature, but many are mere tests of recall of information. A recent book 2 is a step in the right direction, with numerous biochemical problems with a medical flavour. Of course, there is always the caseoriented approach of Montgomery's textbook. 3 However, we still find it necessary to devise our own problems, or to adapt those described by others. In the second year of the course, our medical and dental students take a module entitled 'Genetics', in which they study the principles of the population, cellular, biochemical and molecular basis of human genetics, and the clinical relevance of these topics. One aspect of the biochemical and population genetics element concerns protein polymorphism. The inheritance of multiple molecular forms of a protein, governed by the HardyWeinberg Law, has been fully described by Harris. 4 In the past, analysis of isoenzymes and polymorphisms of plasma proteins was widely used for the purposes of forensic medicine, paternity testing, and genetic counselling. These days, such approaches have been largely superseded by DNA-based methods, such as genetic fingerprinting and the polymerase chain reaction. However, an understanding of population genetics and of biochemical genetics is still essential for medical and dental students. We therefore devised a problem based on a simulated enzyme polymorphism. The problem Imagine that you have just developed a staining procedure
Features Section: Problem-based Learning Editor: C A S m i t h , the M a n c h e s t e r M e t r o p o l i t a n U n i v e r s i t y , U K
It will have been apparent that the Problem-based Learning Page in the last issue of Biochemical Education went somewhat awry. Unfortunately the article by Professor Campbell was transposed with a general review of problem-based learning by myself et al! 1 We apologise for the error. The Problem-based Learning Page in this issue therefore has two articles: one by Professor Campbell, the other by Drs Welch and Carroll. To reiterate the last issue, the article by Professor Campbell is different from anything other submission which the Page has published previously. It does, however, make a number of points pertinent to Biochemical teaching/education which most would think justified and many would own up to at least some of the criticisms. Professor Campbell is critical of a number of aspects of PBL and supports his views by stating that there have been a number of reports critical of PBL, for example Berkson (1993). 2 However, Berkson 2 is not by any means solely critical and sees a number of merits in PBL. Professor Campbell then develops his paper to outline an underlying rationale for a 'basic' Biochemistry syllabus and lists those topics which he feels should be covered in a lecture programme. Professor Campbell's submission contains much material to ponder on, and Biochemical Education, and the PBL Page in particular, would be delighted to receive letters and views on the topics he has raised. The article submitted by Drs Welch and Carroll is an excellent example of the practical use of PBL and I commend it to you. As always, the Problem-based Learning Page welcomes ideas and suggestions on the teaching and assessment of biochemistry and related disciplines. References 1Smith, C A, Powell, S C and Wood, E J (1995) Developing problemsolving skills in students: an esential corollary to problem-based learning in biochemistry and related disciplines. Biochem Educ 23, 149-152 2Berkson, L (1993) Problem-based Learning: have the expectations been met? Academic Medicine 10, $79-$88
B I O C H E M I C A L E D U C A T I O N 23(4) 1995
0307-4412(95)00076-3
Some Thoughts on Problem-based Learning PETER N CAMPBELL University College L o n d o n Gower Street L o n d o n W C 1 E 6BT, UK
Introduction Every year since I began teaching medical students in 1946, I have heard calls for changes in the undergraduate medical curriculum. These have come from a number of different directions, sometimes because of a change of Dean, sometimes because it is necessary to introduce new subjects, and sometimes because of complaints that the course is overloaded with facts. As readers of this journal will know j the latest call is from the General Medical Council which has issued a report entitled "Tomorrow's Doctors". 2 This Report recommends that there should be a core curriculum to which options can be added. It also demands a substantial reduction in the amount of factual material that students are expected to assimilate and places more emphasis on problem-based learning (PBL). I have been impressed in my visits to medical schools in various countries by the extent to which the PBL system has been so readily adopted by those in authority considering that there have been a number of critical reports among the many which have advocated PBL (see for eample Berkson3). Role of facilitators It is interesting that in the U K there is an increasingly strong feeling against PBL which has even been used in primary schools. I quote from The Times of 28th January 1995: "Teachers were instructed to present themselves as facilitators - - there simply to guide the children's own processes of discovery - - rather than as sources of expertise. The most pejorative word in the education lexicon became 'didactic'. Teachers were not to instruct - they were simply to supervise the child's quest for knowledge." This may be an extreme view of PBL but ! have certainly detected elements of it in the application of P B L to the education of medical students. The initial enthusiasm for PBL came from medical schools in Canada and the USA where the education of medical students is largely a postgraduate activity. In this respect such medical schools are almost unique in the world, for in virtually all other countries the medical
203 course starts with entry from school at about 18 years of a g e . The report by Berkson 3 concludes that P B L has much merit provided that the class size in toto is small, eg not m o r e than 40. Even then it has disadvantages in that it is usually not possible to find enough expert teachers, so that those who guide the P B L sessions are what is termed ' n o n - e x p e r t ' . As I have mentioned, those who favour P B L do not mind this, for the facilitators are not there to provide 'mini-lectures' but to guide the discussion in a fruitful manner. T h e r e are other requirements for success, such as the provision of numerous tutorial rooms, since the teaching groups should not be larger than about 10 students. T h e r e is also the need for well-equipped library resources.
Background knowledge My experience suggests that those who adopt P B L need to think carefully about the factual material - - the vocabulary - - with which the students need to be equipped at the start, for one cannot have a fruitful discussion without some facts. In the past, biochemists have often been accused of donning the mantle of the new anatomists in that they have d e m a n d e d from the students memorisation of a large body of facts soon to be forgotten. Often I have felt that such criticism had some justification. In serving as an External E x a m i n e r I have found myself protecting the student from teachers who were seeking the regurgitation of facts e x p o u n d e d in a particular lecture. A recent experience as External Examiner showed the dangers of applying P B L to students with very little factual background and of then asking them multiple-choice questions calling for factual minutae. The result was that the students failed not only on the recall of factual knowledge but also showed little ability to handle problems. This is also a conclusion reached by Berkson. 3 It seems to me inevitable that the undergraduate medical curriculum will have to be slimmed down and at least some P B L introduced. Thus the biochemists will have to decide what it is they wish to transmit to the students in terms of facts in perhaps 30 lectures. However, before giving my opinion of what the core might contain I would like to state my position concerning the perennial argument between 'vocational training' and 'university education'.
Education versus vocational training In the U K it would be fair to say that until recently we had two kinds of medical schools. Those that were part of a multifaculty university and those (mostly in London) that stood alone, being closely allied to a hospital. For some time various reports have argued against the stand-alone schools on the grounds that the medical students should have the opportunity to experience a broadly-based education in their preclinical years. This is very much in line with the training of other professions such as law and accountancy which have m o v e d towards the acquisition of a university degree before the vocational training. It seems to me right that medical doctors should have a broadly-
B I O C H E M I C A L E D U C A T I O N 23(4) 1995
based education not only on general grounds but also because they should be equipped to maintain their interest and knowledge of their profession for the 40 years they might expect to practice. As biochemists we have been fortunate in that we can now apply sound scientific principles to an understanding of the metabolism of both normal and pathological states. Thus I feel we can try to steer a middle course between education in depth and vocational training. The crucial question is to ask always why one is teaching a particular subject. If the answer m a k e s no sense on either educational or vocational grounds then it should be stopped.
Chemical background An immediate concern for a biochemist is the extent to which a knowledge of chemistry is required for entrants to the course. In the U K , where the different medical schools have authority over the admission of students, there has been much variation in the qualifications d e m a n d e d , but a c o m m o n requirement has been a good standard in chemistry form high school. There is now some relaxation in this respect and it is certainly interesting that in m a n y countries, such as G e r m a n y , there are no d e m a n d s for a demonstrated knowledge of chemistry, or indeed of any other science subject. While we can certainly overdo our emphasis on rote learning of chemical formulae so that the biochemistry course comes to be seen by the students to be dominated by the Krebs Cycle, or the structure of the ketone bodies, we are surely right in expecting an understanding of the meaning of chemical formulae in terms of structure and an appreciation of the characteristic properties of carboxylic acids, amino acids, lipids and carbohydrates, etc. The basic concepts of inorganic and physical chemistry are also essential. (My concern is to avoid the necessity of failing a student who has no m o r e ability to c o m p r e h e n d a chemical formula than I have to read Chinese.)
General principles At the start of a course it would be good to emphasise some general principles overriding the biochemical events in all types of living cells. I was always attracted by the first chapters of the various editions of Lehninger's text books. H e started by stating that the challenge to the biochemist was to explain how it is that living things are c o m p o s e d of lifeless molecules. The two most characteristic properties of living organisms is their ability to extract and transform energy from their environment and their ability to reproduce themselves, ie their capacity for precise self-replication. H e went on to explain that the chemicals involved are similar in all living things, that the energy currency is always ATP, and that the transmission of genetic information is always through nucleic acids. The function of enzymes which catalyse metabolic reactions at amazing speed and with practically no byproducts is crucial. A n o t h e r feature is the versatility of the chemicals involved, such as the amino acids which not only serve as building blocks for the proteins but also are
204 important in metabolism, and the same applies to the nucleotides. In terms of the economical use of energy, Lehninger indicated that there was careful conservation, although I am not too sure if this is really true in view of the loss of expensively constructed macromolecules during the maturation of nucleic acids and proteins for example. Living cells can be rather profligate in terms of energy. The metabolic turnover of the body constituents may also appear to be wasteful of energy but is in fact a good way to control metabolism, ensure that there are no pile-ups and that there are no useless molecules in the cell. The advantages of confining the different areas of metabolism within membranous organelles should be described as well as the corollary that proteins need to be targeted to the various organelles. Finally, and most importantly, the concept of structural complementarity needs to be emphasized whereby small molecules 'fit into' macromolecules as in enzyme action, signalling by means of membrane bound receptors and antigens interacting with antibodies. This complementarity is also important in ensuring that no molecules of DNA are synthesized without a DNA template.
Core material The lectures or didactic presentations might cover the following topics: (1) Types of cell, prokaryotes, eukaryotes, viruses, organelles, (2) Structure of amino acids and proteins, (3) Structure and function of enzymes (4) Nucleic acids (5) Protein synthesis (6) Recombinant DNA (7) Molecular cell biology (8) Carbohydrate chemistry (9) Nitrogen metabolism (10) Lipid structure (11) Carbohydrate metabolism (12) Lipid metabolism (13) Oxidative phosphorylation (14) Interrelationship between carbohydrate and lipid metabolism (15) Diabetes, (16) Membrane structure and function, (17) The structure and function of vitamins (review). However, some of this material might be assigned to students to learn and understand by 'selfinstruction', the 'lectures' being used for highlighting key areas and interconnections. In the above list, which as I have previously indicated could take about 30 hours, I have particularly avoided examples of the application of biochemistry to the aetiology of specific diseases, except diabetes mellitus, since these would form the basis of subsequent problem sessions. I include diabetes since the interrelationship between carbohydrate and lipid metabolism is at the heart of metabolism. References i Higgins, S J (1994) All Change in Britain's Medical Schools, Biochemical Education 22, 66-69 2Tomorrow's Doctors, Recommendations on undergraduate medical education, December 1993, published by the General Medical Council, 44 Hallam Street, London WIN 6AE, UK 3Berkson, L (1993) Problem-biased Learning: Have the expectations been met? Academic Medicine 10, $79-$88
BIOCHEMICAL EDUCATION 23(4) 1995
0307-4412(95)00113-1
A New Erythrocyte Enzyme Polymorphism? SIMON G WELCH and MARK CARROLL
Biochemistry Department Queen Mary & Wesrfield College (University of London) London E1 4NS, UK Introduction The curriculum followed by medical and dental students at Queen Mary & Westfield College emphasises several aspects of independent learning, including a problembased approach.l Within a programme of student-directed learning, course organisers incorporate clinically orientated case-studies in which students are asked to address the underlying principles by means of a series of questions. Their answers are discussed with a tutor at a subsequent tutorial. Solving a clinical biochemical problem thus gives the students some feedback on their understanding of the course material, and also emphasises to them the medical relevance of the subject. In our experience, it is not easy to find problems with a suitable content and at an approriate level of difficulty. Most modern textbooks of biochemistry include some questions of a problem-solving nature, but many are mere tests of recall of information. A recent book 2 is a step in the right direction, with numerous biochemical problems with a medical flavour. Of course, there is always the caseoriented approach of Montgomery's textbook. 3 However, we still find it necessary to devise our own problems, or to adapt those described by others. In the second year of the course, our medical and dental students take a module entitled 'Genetics', in which they study the principles of the population, cellular, biochemical and molecular basis of human genetics, and the clinical relevance of these topics. One aspect of the biochemical and population genetics element concerns protein polymorphism. The inheritance of multiple molecular forms of a protein, governed by the HardyWeinberg Law, has been fully described by Harris. 4 In the past, analysis of isoenzymes and polymorphisms of plasma proteins was widely used for the purposes of forensic medicine, paternity testing, and genetic counselling. These days, such approaches have been largely superseded by DNA-based methods, such as genetic fingerprinting and the polymerase chain reaction. However, an understanding of population genetics and of biochemical genetics is still essential for medical and dental students. We therefore devised a problem based on a simulated enzyme polymorphism. The problem Imagine that you have just developed a staining procedure