Enhanced podcasts for teaching biochemistry to veterinary students
Abstract
The teaching of biochemistry within medical disciplines presents certain challenges; firstly to relay a large body of complex facts and abstract concepts, and secondly to motivate students that this relatively difficult topic is worth their time to study. Here, nutrient biochemistry was taught within a multidisciplinary module as part of an undergraduate veterinary curriculum. The teaching approach was initially focussed on a mixture of didactic lectures and student-centred activities such as directed group/self learning. In subsequent years the core didactic lectures were replaced with enhanced podcasts covering the same material, along with the introduction of student presentations delivered within groups with both peer and facilitator assessment. These changes were accompanied by an increase in the time dedicated to this topic to allow sufficient time for students to work through podcasts and prepare presentations. The combination of these changes resulted in significant improvements in student performance within an in-course biochemistry long essay. These changes in the teaching approach, and particularly the introduction of extensive podcasts, was well received by students who perceived the process of going through the podcasts as time consuming but allowing them flexibility in both the pace that they studied this topic as well as the location and times that they studied it. BIOCHEMISTRY AND MOLECULAR BIOLOGY EDUCATION Vol. 39, No. 6, pp. 421–425, 2011
INTRODUCTION
Within medical disciplines, the motivation of students to study biochemistry may involve an innate desire for knowledge, to gain knowledge to inform future career roles and to pass assessments to progress on the course. I would suggest the latter may well be the main driver for most students. Biochemistry presents a relatively difficult subject to study, it contains a distinct “language” of names, processes and rules, it demands the retention of a large volume of facts as well as the understanding of abstract concepts [1-3]. When considering how this fits into the broader medical curriculum, students will be allotting only a small proportion of their time to studying this topic and this will be amongst other topics which may well reward their time more efficiently in terms of ease of understanding and assessment grades. In combination, this presents a considerable set of challenges to overcome when teaching biochemistry to medical faculty students: to efficiently relay the facts, to promote the understanding of the biochemical concepts and to motivate students that the topic is worth their time.
At present, there is an ever increasing range of “teaching technologies” that are available to try and enhance the learning experience of students. These include e-learning developments such as online learning environments and the use of vodcasts/podcasts to relay teaching. Podcasts are audio files and can be accompanied by coordinated visual presentations such as powerpoint presentations (enhanced podcasts), and vodcasts are video recordings of teaching material. Examples in the literature often show these methods being used to provide whole lectures electronically to students after they have been delivered live [4-6]. In addition, short podcasts, lasting just a minute or two, have been used to relay learning outcomes and resource information for student-led investigations [7]. These formats of relaying teaching to students have, on the whole, been well received and the underlying fear of their use adversely affecting student attendance at teaching classes has largely been unfounded [4-6]. On this topic, Lonn and Teasley concluded that “podcasting at least offers no more threat to standard teaching practices than coursepacks and at best offers new opportunities to restructure classroom face time” [4]. This is an interesting point, podcasts and other e-learning strategies do not just provide an alternative or addition to lectures for relaying information to the student; they also allow flexibility in how student contact time is used. With core knowledge delivered within the podcasts, contact time can be used to enhance the learning and understanding of this knowledge, for example by using inductive learning techniques [8]. Student's themselves have also suggested the use of podcasts for topics that are difficult to understand or where the lecture delivery is not clear [5]. In addition, the use of e-learning tools can directly enhance the understanding of complex topics. For example, molecular visualisation software and web-based animation are used to enhance the understanding of molecular structures [9]. Such tools have even combined with conferencing software to carry out live, interactive online tutorials [10].
In terms of teaching biochemistry it seems that podcasts have the potential to offer a significant advantage to students, that is they can work through this difficult topic at their own pace and review areas of weakness repeatedly and after further research [4, 6].
This study will describe the teaching of biochemistry to second-year veterinary students, the difficulties encountered and the application of podcasts to address some of these.
METHODOLOGY
The study examines the use of podcasts to replace traditional lectures in the delivery of a biochemistry topic within the wider context of an undergraduate veterinary module and curriculum. The main aims were to determine the effect of changes on the student's performance within in-course long essay assessments, and also to determine the students' attitude to the different teaching methods employed.
Students in the School of Veterinary Medicine and Science (University of Nottingham, UK) are taught over a 5-year curriculum with the first 2 years focussed on basic science subjects with integrated clinical examples. This teaching is delivered within “body system-based modules” where topics, such as the “gastrointestinal system” (GI) or “musculoskeletal system” for example, integrate multiple basic science topics. The module of interest here, GI, is a second year module delivered over 11 teaching weeks, encompasses ∼270 hours of teaching. The module includes topics such as anatomy, physiology, biochemistry, microbiology, parasitology and toxicology; all when related to the GI tract and associated organs. The potential benefits of such a curriculum design are the promotion of an integrated understanding of the body system being studied. Each week is timetabled to include lectures, practical sessions, and student-led learning sessions to further investigate topics and/or to relate new knowledge to clinical situations. Student-led learning sessions include facilitated problem-based learning (PBL) as well as nonfacilitated directed-self learning (DSL) and directed-group learning (DGL).
Here, we will consider the delivery of a core biochemistry topic within the GI module: nutrient biochemistry. This topic covers concepts of energy use and storage under distinct physiological conditions and includes a range of biochemical pathways and biological control strategies. The Veterinary course at the University of Nottingham started in 2006, and the first running of the GI module was in the 2007–2008 academic year. In this first year (Year 1), nutrient biochemistry was delivered within three lectures and was supported by a further lecture aimed at the understanding of the core biochemistry principles within a clinical case, bovine ketosis. Further delivery included DSL sessions where students worked through short-answer questions (SAQs), two clinical cases and a web-based interactive tutorial to integrate knowledge delivered within the lectures. This delivery strategy combined so called “teacher-centred learning” (lectures) and “student-centred learning” (directed self/group learning). In terms of the duration of this teaching, this involved four contact hours and three other timetabled hours for directed-student learning. The content of the lectures and associated materials were reviewed by two experienced teachers involved in module design and the overriding feedback was that the course material was comprehensive and was delivered in appropriate sessions. In addition students were provided with clear learning outcomes to judge their knowledge and understanding against.
In the subsequent year (Year 2) the delivery moved teaching away from “traditional” lectures to a more complete student-centred learning experience by utilising e-learning strategies such as podcasts. The same material from the 3 × 1 hour lectures in year 1 was made into 18 enhanced-podcasts, audio description of the material with accompanying, synced powerpoint presentations. Each podcast lasted approximately between 5 and 13 minutes (Table I). In addition, short introductory lectures were used covering the broad topics, and the clinical relevance DSLs were converted into a facilitated PBL case. The final change was that students were directed to prepare two 15 minute presentations to be delivered within a team of 4–5 students to a similar number of their peers and a facilitator. The topics for the presentations were designed to integrate knowledge delivered within the podcasts. All other DSL sessions remained the same. This teaching approach had the same contact hours as before but the hours for directed-student learning were increased from 3 to 14 hours to allow more time for students to work through the podcasts and prepare presentations.
| Podcast topic | Duration | Learning objectives |
|---|---|---|
| Nutrient utilization: introduction | 6′48′′ | Define energy, its units and how energy is used |
| Describe the sources of energy in the absorptive state | ||
| The absorptive state: energy from glucose | 12′17′′ | Describe the utilization of glucose for energy metabolism under aerobic and anaerobic conditions. |
| Describe the role of glycolysis in nutrient metabolism. | ||
| Describe the role of the TCA cycle in nutrient metabolism. | ||
| Describe the role of oxidative phosphorylation in nutrient metabolism. | ||
| Describe the role of the Cori cycle in nutrient metabolism. | ||
| The absorptive state: energy storage molecules from glucose | 10′35′′ | Explain how energy is stored: describe the synthesis of glycogen and triglycerides |
| Describe the role of lipogenesis and the pentose phosphate cycle in nutrient metabolism. | ||
| Describe the role of glycogenesis in nutrient metabolism. | ||
| The absorptive state: lipid transport/utilization | 5′08′′ | Describe the transport of lipids by lipoproteins |
| Describe the utilization of triglycerides as energy sources. | ||
| The absorptive state: volatile fatty acids | 5′34′′ | Describe the utilization of volatile fatty acids as energy sources |
| The absorptive state: amino acid utilization | 5′17′′ | Describe the utilization of amino acids as energy sources |
| The absorptive state: summary | 8′28′′ | – |
| The post-absorptive state: glycogenolysis | 6′26′′ | Describe the utilization of energy stores during the post-absorptive state: glycogen mobilization |
| The post-absorptive state: gluconeogenesis | 9′17′′ | Describe the utilization of energy stores during the post-absorptive state: gluconeogenesis, protein catabolism |
| The post-absorptive state: lipolysis | 7′25′′ | Describe the utilization of energy stores during the post-absorptive state: lipid catabolism |
| Control of metabolism: Metabolic integration | 7′29′′ | Explain why there is a need to coordinate pathways involved in nutrient metabolism |
| Control of metabolism: Hormonal control | 9′24′′ | Explain the role of hormones in the coordination of nutrient metabolism |
| Control of metabolism: AMPK and substrate/product concentration | 10′51′′ | Explain the role of AMP activated protein kinase in the coordination of nutrient metabolism. |
| Explain the role of substrate/product concentrations in the coordination of nutrient metabolism | ||
| Control of metabolism: Enzyme modification 1 | 10′24′′ | Explain the mechanisms by which enzyme's are modified to control metabolism |
| Control of metabolism: Enzyme modification 2 | 11′37′′ | Explain the mechanisms by which enzyme's are modified to control metabolism |
| Control of metabolism: compartmentation | 13′16′′ | Explain the role of compartmentation in the coordination of nutrient metabolism. |
| Control of metabolism: metabolic scenarios | 11′59′′ | – |
| Metabolic diseases | 8′42′′ | Describe the metabolic events that can lead to disease during periods of negative energy balance |
The efficacy of the teaching methods was assessed in terms of the performance of the students in their summative in-course exams. The GI module as a whole was assessed using six long essays with in-course exams scheduled 3 weeks after the delivery of the biochemistry teaching. One of the in-course essays was on nutrient biochemistry with the same essay set for both Years 1 and 2. All essays were marked against standardised marking schedules with the biochemistry essay marked by myself (who delivered almost all of the teaching on this topic). In-course essays made up 20% of the module mark with 80% being assigned to end-of-year, multiple-choice-question (MCQ) exams.
STUDENT PERFORMANCE IN SUMMATIVE ASSESSMENTS
For the GI module, students were assessed in both in-course long essay exams as well as end-of-year MCQ exams. A general held belief, although an oversimplification, is that long essays test higher cognitive skills whereas MCQs are more likely to test knowledge recall [11]. However, studies suggest that a well constructed MCQ may well test higher cognitive abilities [12, 13]. The biochemistry essay under consideration was titled “Describe glycolysis and the role of insulin in the control of this pathway.” Such open questions require more effort to recall facts and simulate them into a logical order than the recognition of a correct answer within an MCQ format. In addition higher marks would require the integration of hormonal regulation of cellular function with knowledge of biochemical pathways and enzyme function. However, this essay still largely tests knowledge recall rather than higher levels of cognitive hierarchy: analysis, synthesis and evaluation. As such, students with sufficient recall of facts would be expected to gain ∼ 40 to 50% in this essay.
With regard to the nutrient biochemistry essay, the performance of students between the two years was significantly different with the students taught using podcasts outperforming those taught using lectures (p < 0.001, two-tailed unpaired t-test; Fig. 1). This was also highlighted when considering the number of students achieving 40+ percent (p < 0.001) as well as 60+ percent (p < 0.001; Fig. 1). When comparing the number of students from each year achieving/failing to achieve these marks, data was set up as 2 × 2 contingency tables and Fisher's exact test (two-tailed) was applied to derive p-values. For all comparisons, when the GI module as a whole was considered there was no statistical difference between students' performance in the 2 years.
Student's performance in a summative in-course biochemistry essay across two consecutive academic years. The average student mark is shown for each year for the nutrient biochemistry essay question or for the module (GI) as a whole (a). The breakdown of student grades is also given (b) as well as the scatter plot of individual student scores for the biochemistry essay along with the mean and standard error of the mean (calculated using the GraphPad Prism software). The numbers of students sitting the exams were 88 and 92 for years 2007-08 and 2008-09, respectively.
Also of note was that the students' performance in end of year MCQs on the biochemistry questions was at least comparable to responses on all topics within the GI module, and this was the case for both years. In Year 1, students gave 69% correct answers for biochemistry questions (11 questions, 1012 responses) compared to 60% correct answers for the module as a whole (170 questions, 15,640 responses). In Year 2, students gave 64% correct answers for biochemistry questions (15 questions, 1440 responses) compared to 62% correct answers for the module as a whole (180 questions, 17,240 responses). These exams were made up of “traditional” MCQs with a single correct answer and 3–4 distractors (∼ 45% of questions), extended matching questions (EMQ; ∼ 25% of questions), diagrammatic questions (∼ 10% of questions) and assertion-reason questions (ARQs; ∼ 20% of questions), some of which formed case-based question sets. Making the assumption that questions on biochemistry and those for the whole module were of similar difficulty, these data would indicate that regardless of teaching method, by the end-of-year exams the students' knowledge of biochemistry was at least comparable to that of the combined module topics.
The changes in the teaching from Year1 to Year 2 have had a significant effect upon the exam performance of the students when considering in-course long essays and have not had any apparent detrimental effect on student performance in end-of-year MCQ exams. The major changes in teaching were 1) the replacement of didactic lectures with short summary lectures and enhanced podcasts, the latter covering all of the core learning outcomes for the topic, 2) the inclusion of student presentations at the end of the time that the material was delivered which were peer and facilitator assessed, and 3) the provisions of extra time in the timetable for the students to go through podcasts and prepare presentations. The combined effects of these changes are obvious but it is not possible to know what contributions individual changes have had on the student performance. Previous studies have indicated that whilst the use of podcasts can enhance the student experience it may have little effect on exam performance [14]. However, it may be that the level of benefits gained by employing this form of knowledge delivery is likely to be dictated by the subject under study. It seems likely that the provision of podcasts for subjects such as biochemistry that have high levels of abstract information will have the advantage of allowing students to go through material at their own pace and concentrate on individual areas of weakness. The student performance may also be influenced by the hours available for this subject in the timetable. Overloading of information and/or perceived unreasonable workload has been shown to adversely affect motivation and discourage a deep-approach to learning [15]. The inclusion of group presentations increased the level of inductive learning for this subject within Year 2 and as such this may have contributed to improved performance in essay type exams [16]. The latter is also likely to have increased student motivation to study this topic because the material within the podcasts was directly assessed within the student presentations [2]. An increase in student motivation for the topic could be significant, as stated previously biochemistry is perceived as being a difficult and time-consuming topic to study. Given the limited time available to study before the essay exams, low motivation for the topic may lead many students to strategically decide that other topics within the module will be easier/more beneficial for them to study.
STUDENT FEEDBACK: STUDENT EVALUATION OF MODULE
Student feedback was obtained from anonymous questionnaires on the module as a whole which included the following 3 free response sections: “What did you like about this module?”, “How could this module be improved?” and “Any further comments about the module”. Comments were collated from Years 1, 2, and 3; with delivery of nutrient biochemistry teaching within Years 2 and 3 being basically the same. Year 1 feedback included just three comments on the nutrient biochemistry topic (representing <5% of the free responses given on the module), and all three were positive, listing this topic in response to the question “What did you like about this module?” (Table II). For Years 2 and 3 there were 44 positive comments about the subject and 17 negative comments (representing 26% of the free responses on the module). Where students elaborated on these positive comments they mainly focussed on the perception that this learning method allowed them greater flexibility in both the pace and location of their learning (Table II). The negative comments mostly focussed on the perceived lack of enough time to go through the podcasts (Table II).
| Academic year | Comments |
|---|---|
| 2007–2008 (lecture-based delivery) | Positive comments: |
| “I also very much enjoyed the day spent on the absorptive and post-absorptive state” | |
| “the nutrient utilization lectures were delivered very well and they helped increase my knowledge of this subject” | |
| “The nutrient utilization lectures were good” | |
| 2008–2009/2009–2010 (podcast-based delivery) | Positive comments included: |
| “The podcasts for metabolic lectures enabled a very thorough way of learning which also gave me more responsibility for my own learning. I enjoyed doing them in my own time and would welcome them for more of our lectures throughout the year” | |
| “The podcasts during nutrient utilization were an interesting way of learning, and although fairly time consuming and quite difficult to work through I think they helped me to actively learn the material. If we had just been delivered it in lectures I'm sure I wouldn't have listened as intently and so would still have spent longer going through them again than I did going through the podcasts by myself” | |
| “The podcasts took a long time to complete and go through but afterwards I really felt I knew and understood the topic” | |
| “The self learning week, I think the fact that I was given the responsibility and a chance to pace my own learning is a great way of enhancing my knowledge” | |
| “I liked the availability of recorded lectures podcasts because sometimes in lectures I feel like I do not have enough time to synthesize thought, I would easily miss a point while typing up the previous point” | |
| “The podcast week was excellent made learning a complicated topic a lot easier and less tedious allowed us to study at home which saved a lot of time and money not having to travel into uni every day the podcasts allowed you to work at your own pace to ensure full understanding of the topic far more lectures should be delivered in this way” | |
| Negative comments included: | |
| “Podcasts—too many would have been good to have some lectures or have notes (in word format) as it took me a long time to make notes due to having to stop and start podcasts” | |
| “Have more help with the podcasts and some lectures also covering the content of the podcasts” | |
| “Although the nutrition and metabolism podcasts were a really good idea in principle, the time allocated should be rethought” | |
| “Maybe could have had a few more lectures on the content of the Podcasts. I thought they did work quite well but I found myself unsure about what was being said and which bits were relevant to write down hence writing down everything that was said and this took a lot of time. The podcasts on the whole took me way longer than a lecture [would] have done”. |
For all years, student evaluation of modules contained many examples of negative feedback on individual lectures and topics. As such the student feedback on the Year 1 teaching of biochemistry would indicate that the teaching was not perceived as being a weakness or in need of improvement within the module as a whole. Feedback in the following 2 years after the implementation of the changes in biochemistry teaching was markedly different. The use of enhanced podcasts to replace lectures evoked a high response rate from students and this topic was one of the most commented on aspects of the module. On balance this form of teaching was very well received by the students.
CONCLUDING REMARKS
Teaching biochemistry within a medical discipline requires the efficient relaying of a large body of facts, promoting the understanding of abstract biochemical concepts and motivating students to study this “difficult” topic within a packed curriculum [2, 3]. Traditionally such teaching is dominated by didactic lectures [1]. Here, nutrient biochemistry was taught within the GI module as a mixture of didactic lectures and student-led activities. Following very poor student performance in a biochemistry essay, enhanced podcasts were used to replace the traditional lectures and a student presentation on the same material was introduced which was assessed by peers and a staff facilitator. These changes were accompanied by an increase in the time allocated to this topic to allow students to go through podcasts in their own time and to prepare the group presentations.
These combined changes resulted in a significant improvement in student performance in the same biochemistry essay. The changes did not have any negative impact on student exam performance in the module as a whole or in end-of-year MCQ exam performance with regard to questions on nutrient biochemistry.
Podcasts are often used to provide material after it has been delivered “live” within a lecture [4-6]. In contrast, this study used podcasts to replace traditional lectures with the main advantage, as recognised by students, being that this allowed the material to be studied at a pace and location suitable for each individual student, and allowed areas of weakness to be addressed. This study would indicate that the use of podcasts can enhance student understanding of a biochemistry topic when they are accompanied by 1) sufficient time to allow their study, and 2) suitably motivating assessments, such as student presentations of the podcasted material.
