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Start teaching with amino acids and proteins!
110
Letters to the E d i t o r From H V Wyatt
Relaxation of Examination Regulations Dear Sir, l welcome Dr Reed's proposal for use o f a metabolic map by students in examinations. 1 If we wish to test factual recall we should examine by using multiple choice questions ( M C Q ) or single word answers: this should, but rarely does, start a long argument about what we should examine and hence what we should teach. If one allows the student to use books, maps or his o w n notes in an examination, one should be examining some other aspect o f learning. I have used open bookunsupervised-unlimited time examinations 2'3 and open book selfcorrecting examinations. 4 There are special difficulties in using these different and unfamiliar modes o f examining. The first is that the students, even if warned, expect to find the answer in the books, not the clues to the explanation o f the question. Many students then misunderstand the question in order to make it fit the facts which they have found. Others spend e n o r m o u s time searching for the answer in the books, which o f course do not contain it. Some students get bored with looking and some cannot restrain the opportunity to pour everything, relevant and irrelevant, from book to paper. In short, students have become accustomed to certain responses in examinations and find it difficult to adjust to a new situation. This is particularly true if the mutant form o f examining occurs in one subject only or in one part o f a subject. Conflicts arise, l think that students should be given practice in such new techniques because, as Dr Reed suggests, we can then test different skills. M y attempts to measure different skills 5 have resulted in a far greater spread o f marks 2 than those o f m y colleagues - - with attendent difficulties with them and students! For the lecturer w h o wishes to experiment, there is little time for allowing students to practice a new technique, especially as this should include periods for discussion o f the aims o f the examination before and students' performance after, l believe that far more would experiment if they were more aware o f the difficulties. For instance, m y final-year students have for many years accepted the prospect o f problem-type questions to which there might be no single correct answer: so far none has preferred a more conventional examination. It is a failure o f our scientific societies, our subject education journals and ourselves that our papers on education mirror our scientific papers. There are no papers which deal in detail with h o w we should teach or examine specific items. 1 look forward to future investigations o f student responses, mistakes, etc, in relaxed examinations and o f the changes in teaching which have resulted. H V Wyatt
Department of Biology University of Bradford Bradford BD7 1DP, UK
References I Reed, F B (1981) BiochemEd 9, 21-22 : Wyatt, H V (1972) Getting the message over - - an examination of the teaching of the genetic code. J Biol Ed 6, 73--81 3 Wyatt, H V (1975) An introductory microbiology course based on the Clothier Report. J Biol Ed 9, 21-25 4 Wyatt, H V (1977) Investigating an epidemic:, a seven part simulation used in teaching. IntJ Epid6, 173-176 Wyatt, H V (1973) Examinations examined. J Biol Ed 7(4), 11-17
From R W McGilvery
Synthetases and Synthases Dear Sir, O n e point can be settled in the disagreement between Professors Metzler and Karlson on the merits ofsynthetase and synthase. I invented the word synthetase while a graduate student in Philip C o h e n ' s laboratory at the University o f Wisconsin. It was defined as applying to 'those enzymes creating a new molecule by the elimination o f water between to substrate molecules, excluding the formation o f phosphate esters and anhydrides • . . The generic term, synthetase, would apply to all enzymes forming amides and esters'. (] Biol Chem 171, 121 (1947): Cohen had me looking at the synthesis ofhippuric acid as a model for peptide bond synthesis. Good try, but definitely no cigar.) While it is true, as Mr Justice Holmes said, 'A word is not a crystal,
BIOCHEMICAL EDUCATION
9(3)
1981
transparent and unchanging, but the skin o f a living thought', there is benefit for all, especially for students, in being precise and consistent in nomenclature. Precision need not preclude inventiveness and occasional h u m o u r , but we need s o m e m e c h a n i s m to keep special interest groups from confusing everyone. Witness the designation o f gene sequences, the naming o f collagen peptides, clotting factors, or complement factors. It is also difficult to draw the line between the light touch and mere cuteness. If the physicists don't regret starting on the path to 'color' and 'charm', they o u g h t to.
R W McGilvery
University of Virginia Charlottesville, Va, USA From P Karlson
Start Teaching with Amino Acids and Proteins/ Dear Sir, In his editorial on the order o f topics in teaching medical biochemistry, Dr Saffran rightly points out that the old approach, starting with the organic chemistry o f carbohydrates, proteins and lipids, is certainly not the best way to introduce medical students to biochemistry. He then asks the question ' w h y not start with what is by far the simplest c o m p o u n d of biochemical interest, the fatty acid?' M y answer to this question is: because you soon need a knowledge o f enzymes and enzyme catalysis in discussing any biochemical field. It is true that the structure o f fatty acids is very simple, and also that their metabolism, ie the route o f [3-oxidation, is easy to understand. However we do not live in the 1930s when the elucidation o f the main pathways of metabolism was the aim o f biochemical research. Teaching biochemistry today, we would like to introduce the control o f metabolism, the concept o f multi-enzyme complexes in fatty acid biosynthesis, and m a n y other items for which a knowledge o f e n z y m o l o g y is needed• In a textbook I first wrote twenty years ago, which has been translated into fifteen languages, and which appeared in its eleventh edition last year, I start out with amino acids, peptides and proteins. The structure o f amino acids is only slightly more complex than the structure of fatty acids. It is not more complex than that ofphospholipids, glycolipids, etc. It is true that the student has to acquire a vocabulary of twenty amino acids which is o f course more difficult than to learn the names o f half a dozen fatty acids. O n the other hand, medical students are used to learning names and structures from their anatomy, thus they should easily be able to memorize and comprehend the twenty amino acids. From there onwards, there is a direct line to the primary structure o f smaller peptides and polypeptides, the range o f protein chains, the secondary and tertiary structure o f proteins, and an understanding o f the function o f enzymes on the basis of an active centre which brings together the reactants, thereby accelerating the rate o f reaction by a factor o f 109-1012. With this knowledge, the teacher can start into biochemistry at any point he wishes. Fatty acid metabolism is a topic which couldbe dealt with next. However, I found it convenient to treat fatty acids together with more complex lipids in the context o f biological membranes. O n e needs a knowledge o f biological m e m b r a n e s to really understand biological oxidations and ATP-synthesis. Indeed, this chapter in the last edition o f m y textbook is not entitled 'biological oxidations' as is customary, but rather 'energy conservation in biological membranes'. 1 agree with Dr Saffran that the order o f topics is very important in teaching medical students. I also agree that the time-honoured approach is probably the worst one can think of. There are, o f course historical reasons: the chemistry of carbohydrates developed m u c h earlier, around the turn o f the century, than the organic chemistry o f more complex lipids to say nothing o f the structure o f proteins. P Karlson
Institute of Physiological Chemistry Philipps-University Marburg Marburg, West Germany
BIOTECHNOLOGY
APPRECIATION COURSE
A one-day Biotechnology Appreciation Course will be held at the University o f Surrey on Wednesday 16 September 1981. The Course is aimed at engineers and scientists wishing to obtain a concise overview o f this rapidly-developing field. Detailed p r o g r a m m e from Mr M A Winkler, Biotechnology Group, Department o f Chemical Engineering, University of Surrey, Guildford, Surrey G U 2 5XH, U K .
Letters to the E d i t o r From H V Wyatt
Relaxation of Examination Regulations Dear Sir, l welcome Dr Reed's proposal for use o f a metabolic map by students in examinations. 1 If we wish to test factual recall we should examine by using multiple choice questions ( M C Q ) or single word answers: this should, but rarely does, start a long argument about what we should examine and hence what we should teach. If one allows the student to use books, maps or his o w n notes in an examination, one should be examining some other aspect o f learning. I have used open bookunsupervised-unlimited time examinations 2'3 and open book selfcorrecting examinations. 4 There are special difficulties in using these different and unfamiliar modes o f examining. The first is that the students, even if warned, expect to find the answer in the books, not the clues to the explanation o f the question. Many students then misunderstand the question in order to make it fit the facts which they have found. Others spend e n o r m o u s time searching for the answer in the books, which o f course do not contain it. Some students get bored with looking and some cannot restrain the opportunity to pour everything, relevant and irrelevant, from book to paper. In short, students have become accustomed to certain responses in examinations and find it difficult to adjust to a new situation. This is particularly true if the mutant form o f examining occurs in one subject only or in one part o f a subject. Conflicts arise, l think that students should be given practice in such new techniques because, as Dr Reed suggests, we can then test different skills. M y attempts to measure different skills 5 have resulted in a far greater spread o f marks 2 than those o f m y colleagues - - with attendent difficulties with them and students! For the lecturer w h o wishes to experiment, there is little time for allowing students to practice a new technique, especially as this should include periods for discussion o f the aims o f the examination before and students' performance after, l believe that far more would experiment if they were more aware o f the difficulties. For instance, m y final-year students have for many years accepted the prospect o f problem-type questions to which there might be no single correct answer: so far none has preferred a more conventional examination. It is a failure o f our scientific societies, our subject education journals and ourselves that our papers on education mirror our scientific papers. There are no papers which deal in detail with h o w we should teach or examine specific items. 1 look forward to future investigations o f student responses, mistakes, etc, in relaxed examinations and o f the changes in teaching which have resulted. H V Wyatt
Department of Biology University of Bradford Bradford BD7 1DP, UK
References I Reed, F B (1981) BiochemEd 9, 21-22 : Wyatt, H V (1972) Getting the message over - - an examination of the teaching of the genetic code. J Biol Ed 6, 73--81 3 Wyatt, H V (1975) An introductory microbiology course based on the Clothier Report. J Biol Ed 9, 21-25 4 Wyatt, H V (1977) Investigating an epidemic:, a seven part simulation used in teaching. IntJ Epid6, 173-176 Wyatt, H V (1973) Examinations examined. J Biol Ed 7(4), 11-17
From R W McGilvery
Synthetases and Synthases Dear Sir, O n e point can be settled in the disagreement between Professors Metzler and Karlson on the merits ofsynthetase and synthase. I invented the word synthetase while a graduate student in Philip C o h e n ' s laboratory at the University o f Wisconsin. It was defined as applying to 'those enzymes creating a new molecule by the elimination o f water between to substrate molecules, excluding the formation o f phosphate esters and anhydrides • . . The generic term, synthetase, would apply to all enzymes forming amides and esters'. (] Biol Chem 171, 121 (1947): Cohen had me looking at the synthesis ofhippuric acid as a model for peptide bond synthesis. Good try, but definitely no cigar.) While it is true, as Mr Justice Holmes said, 'A word is not a crystal,
BIOCHEMICAL EDUCATION
9(3)
1981
transparent and unchanging, but the skin o f a living thought', there is benefit for all, especially for students, in being precise and consistent in nomenclature. Precision need not preclude inventiveness and occasional h u m o u r , but we need s o m e m e c h a n i s m to keep special interest groups from confusing everyone. Witness the designation o f gene sequences, the naming o f collagen peptides, clotting factors, or complement factors. It is also difficult to draw the line between the light touch and mere cuteness. If the physicists don't regret starting on the path to 'color' and 'charm', they o u g h t to.
R W McGilvery
University of Virginia Charlottesville, Va, USA From P Karlson
Start Teaching with Amino Acids and Proteins/ Dear Sir, In his editorial on the order o f topics in teaching medical biochemistry, Dr Saffran rightly points out that the old approach, starting with the organic chemistry o f carbohydrates, proteins and lipids, is certainly not the best way to introduce medical students to biochemistry. He then asks the question ' w h y not start with what is by far the simplest c o m p o u n d of biochemical interest, the fatty acid?' M y answer to this question is: because you soon need a knowledge o f enzymes and enzyme catalysis in discussing any biochemical field. It is true that the structure o f fatty acids is very simple, and also that their metabolism, ie the route o f [3-oxidation, is easy to understand. However we do not live in the 1930s when the elucidation o f the main pathways of metabolism was the aim o f biochemical research. Teaching biochemistry today, we would like to introduce the control o f metabolism, the concept o f multi-enzyme complexes in fatty acid biosynthesis, and m a n y other items for which a knowledge o f e n z y m o l o g y is needed• In a textbook I first wrote twenty years ago, which has been translated into fifteen languages, and which appeared in its eleventh edition last year, I start out with amino acids, peptides and proteins. The structure o f amino acids is only slightly more complex than the structure of fatty acids. It is not more complex than that ofphospholipids, glycolipids, etc. It is true that the student has to acquire a vocabulary of twenty amino acids which is o f course more difficult than to learn the names o f half a dozen fatty acids. O n the other hand, medical students are used to learning names and structures from their anatomy, thus they should easily be able to memorize and comprehend the twenty amino acids. From there onwards, there is a direct line to the primary structure o f smaller peptides and polypeptides, the range o f protein chains, the secondary and tertiary structure o f proteins, and an understanding o f the function o f enzymes on the basis of an active centre which brings together the reactants, thereby accelerating the rate o f reaction by a factor o f 109-1012. With this knowledge, the teacher can start into biochemistry at any point he wishes. Fatty acid metabolism is a topic which couldbe dealt with next. However, I found it convenient to treat fatty acids together with more complex lipids in the context o f biological membranes. O n e needs a knowledge o f biological m e m b r a n e s to really understand biological oxidations and ATP-synthesis. Indeed, this chapter in the last edition o f m y textbook is not entitled 'biological oxidations' as is customary, but rather 'energy conservation in biological membranes'. 1 agree with Dr Saffran that the order o f topics is very important in teaching medical students. I also agree that the time-honoured approach is probably the worst one can think of. There are, o f course historical reasons: the chemistry of carbohydrates developed m u c h earlier, around the turn o f the century, than the organic chemistry o f more complex lipids to say nothing o f the structure o f proteins. P Karlson
Institute of Physiological Chemistry Philipps-University Marburg Marburg, West Germany
BIOTECHNOLOGY
APPRECIATION COURSE
A one-day Biotechnology Appreciation Course will be held at the University o f Surrey on Wednesday 16 September 1981. The Course is aimed at engineers and scientists wishing to obtain a concise overview o f this rapidly-developing field. Detailed p r o g r a m m e from Mr M A Winkler, Biotechnology Group, Department o f Chemical Engineering, University of Surrey, Guildford, Surrey G U 2 5XH, U K .