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Journal of Biological Education ISSN: (Print) (Online) Journal homepage: https://www.tandfonline.com/loi/rjbe20 Unravelling the Central Dogma of Biology in an active way: a case study Lucas Fagundes Silveira, Christian Santos Xavier, Maíra Alexandre Perez, Dandie Antunes Bozza, Lupe Furtado-Alle, Iris Hass & Luciane Viater Tureck To cite this article: Lucas Fagundes Silveira, Christian Santos Xavier, Maíra Alexandre Perez, Dandie Antunes Bozza, Lupe Furtado-Alle, Iris Hass & Luciane Viater Tureck (2021): Unravelling the Central Dogma of Biology in an active way: a case study, Journal of Biological Education, DOI: 10.1080/00219266.2021.1877780 To link to this article: https://doi.org/10.1080/00219266.2021.1877780 View supplementary material Published online: 23 Feb 2021. Submit your article to this journal Article views: 86 View related articles View Crossmark data Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=rjbe20 JOURNAL OF BIOLOGICAL EDUCATION https://doi.org/10.1080/00219266.2021.1877780 Unravelling the Central Dogma of Biology in an active way: a case study Lucas Fagundes Silveira , Christian Santos Xavier, Maíra Alexandre Perez , Dandie Antunes Bozza , Lupe Furtado-Alle , Iris Hass and Luciane Viater Tureck Scientific Education Laboratory, Department of Genetics, Federal University of Paraná, Curitiba Paraná State, Brazil ABSTRACT KEYWORDS In this paper, we describe a dynamic-model as a strategy to teach DNA transcription and translation in an active way. This activity aims to provide learning beyond memorisation through the simulation of molecular pro cesses, stimulating the elaboration of questions and hypotheses by stu dents. The dynamic consists of four steps, starting with different problem situations which provide a context and encouragement to start the activ ity. The next steps connect these problems with DNA transcription and translation, requiring the active participation of students to simulate these processes through a construction of a model based on an iron board and representations of cellular structures, enzymes and genetic sequences fixed in magnets. An implementation experience of this dynamic, applied to 21 undergraduate veterinary students at a public university in the city of Curitiba, Paraná State, Brazil, is also described. Data from pre and postquestionnaires suggest knowledge about DNA transcription and transla tion was improved and some previous mistakes were clarified. Among the positive aspects that were cited by the students, the words visualisation and playful were more frequent, which reflect the didactic aspects of the dynamic. Some points of attention are discussed throughout the paper, as well as educational implications associated with the material and its potential to promote active learning. Genetics; DNA transcription; DNA translation; active learning; model; dynamic Introduction DNA structure and processes associated with its functions, such as replication, transcription and translation are studied at a molecular level in high school and undergraduate courses in biological and health areas. Nowadays, there are many biotechnological processes and products directly or indirectly associated with molecular aspects of DNA in sectors such as: medicine, veterinary medicine, agriculture and industry. Despite molecular genetics being present in our lives, teaching and learning are still challenging. Studies have shown consistent results that indicate an interesting phenomenon: in general, students have some knowledge of concepts in molecular genetics, such as gene and DNA, for example. However, they are unable to connect these concepts to more complex biological mechanisms, such as the determination of phenotypic characteristics (Marbach-Ad and Stavy 2000; Lewis and Kattman 2004; Duncan and Reiser 2007). Some factors contribute to this situation, such as the complex nature of the subject, specific terminologies and abstract concepts (Duncan and Reiser 2007), and the focus on memorisation of terms and processes (Verhoeff, Waarlo, and Boersma CONTACT Luciane Viater Tureck [email protected] Supplemental data for this article can be accessed here. © 2021 Royal Society of Biology 2 L. F. SILVEIRA ET AL. 2008). Thus, strategies that somehow materialise abstract processes and concepts may be helpful for students and teachers. In this sense, there are many images, animations and videos available that are frequently used by teachers to support the learning process (Rutten, van Joolingen, and van der Veen 2012). However, even using these strategies, students continue to have difficulties, and this may be due to their passive role during the learning process. In fact, learning something is an active process, even if it does not involve a practice, because internally we are in an active cognitive process to internalise and accommodate a new knowledge. It is possible to achieve this level of success with an expository class; however, some methodol ogies can offer a path that requires an active role from students, which naturally favours this process. In this sense, active learning can be defined as ‘ . . . instructional activities involving students in doing things and thinking about what they are doing . . . ’ (Bonwell and Eison 1991). Following this approach, students have the opportunity to formulate questions before teachers provide answers, thus, overcoming the memorising process. This is also a natural path to learning, especially in the science field. Strategies that encourage the linking of ideas through questioning allow the incorporation of the scientific method in didactic activities or practices, which develops the student’s ability to elaborate and evaluate questions answerable by science. This is one of the three competencies used by PISA for Development (PISA-D) to measure scientific literacy, together with the capacity to explain a phenomenon scientifically and interpret data and evidence scientifically (OECD. PISA OECD 2017), which are also mobilised in this kind of strategy. In view of the above, in this paper we describe a dynamic-model strategy to teach DNA transcription and translation through an active way, starting with problem situations that encou rage the questioning and the construction of a didactic model. An implementation experience for undergraduate veterinary students is also described, which was important in revealing weaknesses and strengths of the strategy in terms of being in fact an active strategy that stimulates the formulation of questions. In the following sections, the design of the dynamic-model strategy is detailed and the imple mentation experience is discussed, focused on the aims of the material and its potentiality, as well as the changes of students’ knowledge about DNA transcription and translation. We conclude with some educational implications related to the use of this material. ‘Unraveling the Central Dogma of Biology’: an active way to learn The dynamic-model: ‘Unraveling the Central Dogma of Biology’ was designed to bring contextua lisation to abstract processes and to provide an active role to students in the learning process of this content. The fundamentals of this dynamic-model fit the educational goals of active learning (Bonwell and Eison 1991), thus, the following description have to be understood as an active practice, besides the didactic model itself. In summary, the dynamic covers the DNA transcription and translation processes in eukaryotic cells, from cell signalling to protein secretion, under a genetic perspective. The whole dynamic can be divided into four steps: introduction to the problems, general mechanism, detailed mechanism and sharing/conclusion. The construction of a model is the central part of the dynamic. The model itself is based on construction of structures and simulation of processes using magnets and an iron board. The board works as the environment, both intracellular and extracellular, and the magnets are fixed in representations of cellular structures, enzymes and genetic sequences in order to allow the reorganisation of the pieces along the iron board according to the processes’ steps, always prioritising questioning among the students. In order to control the students’ progress during the dynamic, a script was developed (Supplementary Material) containing key questions for each step which have to be answered by the students before they reach the next step. It is an important tool for teachers to ensure that the fundamental concepts are being worked on. JOURNAL OF BIOLOGICAL EDUCATION 3 As every model has its simplifications, once it is difficult to deal with all the details, especially in molecular genetics, some simplifications of our material have to be considered during its applica tion. One important simplification is the transposition of three-dimensional processes and struc tures, such as DNA and cell for itself, to a bi-dimensional model. The tutor or professor has to pay attention to that, in order to avoid misunderstanding of the model. The scale is also a simplification, considering it is unpractical to build models of cellular processes with real proportions. In our case, proteins, DNA and RNA are bigger than cell and nucleus. Some proteins were considered together to avoid an overflow of names; for example, all the proteins contained in the spliceosome were simplified as a great complex. The timeline of the events is a point of attention too, since the model aims to elucidate complex processes, each step is explained at a time. However, in the inner cell environment, these processes might occur simultaneously. A real example: at the start of the preRNA transcription, a five-prime cap is added in the 5ʹ extremity, at the 3ʹ end happens the addition of the poli(a) tail, and the splicing happens along the whole transcription process. In our model, each of these events occurs at a different time. The dynamic-model was developed by four graduated students, under the guidance of professors of the Science Education Lab of the Genetics Graduate Programme at Federal University of Paraná (UFPR), located in the city of Curitiba, Southern Brazil, and applied on the same university in two classes of Veterinary Medicine’s newcomers, in March 2020. The contents approached in this work are far known by professors, along the years, as common points of mistakes for students. The difficulties presented by students have led us to create a different way to teach those contents. The dynamic steps Step 1: Into a real problem In order to capture students’ attention and improve their commitment, five different problems were developed, containing a narrative of a hypothetical situation that students could face in their future as veterinarians. To solve the problems, students have to finish the dynamic, because during the building of the model the concepts to answer the problems are introduced. The five problems can be found in the Supplementary Material and their basic information is presented in (Table 1) Each problem is based on a real gene which is associated to an important phenotype in animals. However, some undesirable traits appear and the veterinarians are asked to solve the mystery and give a complete biological explanation understandable to a lay person. To find out what is happening, students have to follow the path of central dogma of biology: from gene to protein. Each problem has a different cause to the phenotypic variation; thus, it is necessary to finalise the dynamic and know all the processes to find a solution for the problem. The professor can choose to work with the five problems at the same time, one per group of students, or work just one problem with all class students. Thus, in this step, each group has to read the problem, which is important, once the students need to understand all the terms used in the text to fully understand the problem. The possible knowledge gaps may be used to stimulate the active environment. Students should discuss among themselves to share knowledge and try to create hypotheses to answer the problems. They will, eventually, ask for help, and then the professor should act as a tutor, leading to the right path without telling them directly. The materials delivered to students in this step are: the script and one copy of the problem (Supplementary Material). When the problem is fully understood, the class or group can reach the general mechanism step. 4 L. F. SILVEIRA ET AL. Table 1. Summary of the problems used in the dynamic. Problem title ‘What does he have that I don’t have?’ ‘Very exciting vacations . . . .in the farm fish’ ‘The Mini Mammary Glands Mystery’ ‘A sweet dog!’ Gene Leptin ‘Stay healthy . . . If you can!’ REG3G Phenotype Overweight Vitellogenin Eggs that don’t hatch Prolactin Insulin Mutation Adenine to guanine transition at the 6th pair-base Deletion of the 4th pair-base at the 5th exon Underdeveloped Adenine to thymine transversion at the last base of the 3th exon udder and teats. Diabetes Thymine to guanine transversion at the 12th pair-base – Adenine to thymine transversion at the 14th pair-base Get sick with new Thymine to adenine transversion at the 6th pair-base of the 4th diet exon. Change in the splicing site. Note: Each problem has its own text available in the Supplementary Material. Step 2: The general mechanism The general mechanism step consists of a simplification of the signalling-expression pathway and its function is to bring the problem to a molecular level. In this moment, the professor presents to students the iron board and a ‘general mechanism kit’ for each group. Based on the elements available in the kit, the students have to represent the extracellular, cytosol and intranuclear environments, explaining how a gene can be expressed, starting with a signalling molecule (Figure 1). Figure 1. The general mechanism step representing the signalling-expression pathway and the extracellular, cytosol and intranuclear environments bounded by cellular and nuclear membranes. JOURNAL OF BIOLOGICAL EDUCATION 5 The kit elements have generic names for the structures, as an example: signal molecule and protein, and the students have to name those structures properly, using the terms that appeared in the problem. At this moment, the professor role is to manage the learning process, preventing the detachment of the theme and asking guiding questions to lead the students. At the end, the students should be able to perceive the relationship between an extracellular stimulus and the transcription of a gene, placing the process in a cellular and physiological context. It is common to learn about DNA replication before DNA transcription and translation, and some students may confuse these processes by thinking that before a gene is transcribed it must be replicated. Thus, this step also works as a way to differentiate these processes from replication of DNA, regarding the moment in the cell cycle, stimulus and structures involved. The materials delivered to students in this step are: an iron board (1 m x 1 m) and the general mechanism kit containing: lipoprotein membranes (cellular and nuclear), extracellular signal, membrane receptor, mediator 1 and 2, transcription factor, DNA molecule, RNA molecule, RNA polymerase, ribosome and a protein. All these elements are schematic and can be printed and then pasted on a magnetic surface or magnets (Supplementary Material). Step 3: The detailed mechanism The detailed mechanism comes right after the general mechanism step and deals with transcription (Figure 2) and translation (Figure 3) from gene sequences to polypeptides. In the detailed mechanism step, the same iron board is used, however, another kit should be made available to students. The ‘detailed mechanism kit’ for each group contains: two DNA molecules (representing two gene sequences – referring to the phenotypes described in the problems), two RNA strands to fill, two RNA polymerase, two transcription factors; two cap 5ʹ, two spliceosome complex, two SR protein (serine and arginine-rich protein), two U1 and U2 ribonucleoproteins (small nuclear ribonucleoproteins); two poly A tail, two aminoacyl-tRNA synthetase (Supplementary Material) and a genetic code; beyond tRNAs, two ribosomes, 2 pieces Figure 2. The detailed mechanism step representing the DNA transcription from gene sequences. a: The DNA transcription process. The 3ʹ-5ʹ strand is the template strand and the 5ʹ-3ʹ strand is the coding strand. b: The RNA molecule and the splicing process. c: The mature RNA molecule. 6 L. F. SILVEIRA ET AL. Figure 3. The DNA translation process. a: Ribosome structure. b: Protein formation. c: tRNA in details. of 30 cm length wire and amino acids, that the professor must prepare according to the instructions also available in Supplementary Material. The goal of this step is to make the transcription and translation processes as clear as possible through an active way. To achieve this, the students should start from fictitious genic sequences. At the first moment, the students will need to identify all the elements presented. To make this moment as beneficial as possible, the tutor has to ask about all structures, including all the regions of the gene (enhancer, 5ʹ untranslated region, promoter, exon, intron, 3ʹ untranslated region). Other questions can be done too, like questions related to what moment each element acts in each process. When the students got familiar with the material, the detailed mechanism practice can be started. Initially, the transcription should be simulated, for this, the students have to work with the DNA strands. For each gene copy, there are two sequences: a 5ʹ-3ʹ DNA strand and a 3ʹ-5ʹ DNA strand. The 3ʹ-5ʹ DNA strands are already filled and the students should fill the 5ʹ-3ʹ DNA strands with the complementary bases (Figure 2a). Always keeping caution to not confuse them with the replication process. To simplify, only one gene copy from an animal (always homozygous) is represented: one DNA molecule (two strands). Remembering, we have two animals in each problem: one represents the ‘common’ phenotype, and other animal represents the variation of this phenotype, carrier of undesirable trait, thus two DNA molecules are represented in the dynamic. Five well-known genes are used in the problems and their characteristics are described as follows: the mutated insulin gene has two transversions at the beginning of the promoter region, causing a reduction in transcription rate in the mutated animal. The mutated leptin gene also has two transversions, however, in the first enhancer, resulting in a reduction in transcription rate too. JOURNAL OF BIOLOGICAL EDUCATION 7 The vitellogenin mutated gene has a deletion in the last exon that changes the reading frame, changing the terminal sequence of the protein and forming a premature stop codon. The prolactin mutated gene has a transversion in the last base of the third exon, adding a stop codon and shrinking the final protein in two exons. The mutated regenerating islet-derived 3 gamma gene (REG3G) gene has a transversion on the fourth exon, which modify the branch site, resulting in the removal of this exon during the splicing (Table 1). After filling the DNA strands, the students should discuss what elements act in the transcription process, which is the resulting molecule, which DNA strand is used as a mould and why RNA polymerase follows the 5ʹ-3ʹ directionality. Students should act as RNA polymerases and make the DNA transcription, writing the right RNA sequence from the 3ʹ-5ʹ DNA strand (Figure 2a). The 5ʹcap must be added at the beginning of the preRNA formation and the addition of the poli(a) tail at the 3ʹ end. All these processes occurred in the nuclear region of the iron board. After that, the splicing process is performed on the preRNA molecule, always representing the process through the elements available in the kit (Figure 2b). The RNA strands should be cut between introns and exons, forming shorter RNA strands (Figure 2c). A theoretical pause is recommended at this point. The practice can be stopped and the professor can review the main points and check if all the students are keeping up with the pace of learning the processes being taught so far. Ending the pause, the translation process can be started. It starts exactly at the point the students stopped: with de mature mRNA leaving the nucleus. With the help of a genetic code table, the students must build some tRNAs with correct anticodons and amino acids (Figure 3c), and build the proteins using the ribosome model. The ribosome model was made with a half styrofoam ball with 10 cm of diameter cut in two parts and with a squared hole at the centre, to show the two subunits and the sites for the tRNA (Figure 3a). The proteins are constructed by the students using tiny balls of styrofoam spiked in a piece of wire (Figure 3b). At the end of this practical part, all groups will have two proteins: one normal and one mutant from each DNA molecule, and they can return to the problem situation to elaborate a collective answer. It is also important to check the script with the key questions in each step. Then, the professor makes another theoretical pause to review the main points of the translation process and check the students doubts. In the (Figure 4) it is possible to see all the elements in the iron board. Step 4: Answering the problem and sharing the experience This step is important since the groups work with different problems and sharing these different problems with different solutions may bring a whole view of these contents. They do not need necessarily to prepare a formal presentation, just need to talk about and explain the problem and what was the cause of the phenotype variation. Implementation and knowledge assessment Overview In this section are described an implementation experience of the ‘Unravelling the Central Dogma of Biology’ dynamic and changes in students’ knowledge regarding molecular genetics. The dynamic was designed to cover the DNA transcription and translation topics focusing firstyear students of the veterinary medicine course at a public university in Southern Brazil. However, the dynamic is perfectly adaptable to be applied in other courses, only changing the problems context. 8 L. F. SILVEIRA ET AL. Figure 4. The iron board with all the elements. The implementation experience included twenty-one students (divided into two groups), mean age of 20 years. In the Supplementary Material it is possible to see a picture of the implementation experience with some students. In each group, five hours were spent with the dynamic. Firstly, a questionnaire was applied to students (PreQ) to investigate how much they knew about DNA transcription and translation and whether they expected to have difficulties with these topics. After the dynamic, other questionnaire was applied (PosQ), containing the same questions with the addition of two open questions asking the students’ opinion about the dynamic. In each class the students worked in smaller groups containing 4 to 5 students. Each group received: a problem situation that guided the activity, a script with check questions to be followed by the group and supervised by a tutor, a general mechanism kit and a detailed mechanism kit to build the model. Each group was coordinated by the tutor (postgraduate student) and the professor responsible for the class acted as a general tutor, controlling the time, helping on the more complex mediations and executing the theory pauses. The steps that composed the implementation experience are summarised in the (Figure 5) JOURNAL OF BIOLOGICAL EDUCATION 9 Figure 5. Sequence of steps during the implementation process. Note: PreQ: Pre-questionnaire; PR: Problem Reading; GM: General Mecanism step; DM: Detailed Mechanism step divided in: TSC: Transcription; S: Splicing; TP1: First theoretical pause; TRA: Translation; TP2: Second theoretical pause; C: Conclusion; PostQ: Post-questionnaire. Implementation of the dynamic The most important points regarding the implementation experience are described below. The dynamic was applied to four groups at the same time, and the first step was the reading of the problem situation. The problem situations were fundamental to connect the theoretical con cepts and real situations that will eventually be present in the work of a veterinarian. We could observe the reactions among the students: their surprise, insights, doubts, hypothesis formation, discussions and argumentations towards finding an answer to the problem presented; all these reactions created an active learning environment. Moreover, the problem represented a common point, which drove the whole dynamic. The second step consisted of working in a general perspective, connecting elements of the problem with cellular and molecular structures. In this step, the students received the general mechanism kit and the aim was to find the correct position of the elements in an intracellular and extracellular environment (Figure 1), and to explain the connection of this generic elements (such as signalling molecule) with the problem. We observed that this step allowed us to identify some cellular biology misconceptions and, mainly, this step facilitated the contextualisation of transcrip tion and translation as processes which respond to a cellular or/and environmental demand, unlike DNA replication, which occurs in a different phase of cellular cycle. In fact, we have observed that some of our students frequently understand DNA replication as a first process, necessary to continue to transcription and translation of DNA. We can hypothesise that the sequence in which these topics are usually taught have contributed to this situation. The third step aimed to bring the students into a molecular world. In this step, each group received the detailed mechanism kit and they had to build a new mRNA molecule (Figure 2) and the correspondent protein (Figure 3), doing all the processes and understanding concepts, such as: coding and template strand, 3ʹ-5ʹ ends, promoter region, enhancers, homozygous and heterozy gous, genetic code, among others. During the process, it was possible to identify the causes for the unwanted phenotypes described in the problems, providing the necessary biological basis to explain these problems. Before starting the transcription process, the students completed the coding strand of DNA to deal with the base pairing. Nevertheless, we realised that some students had understood that a new DNA strand is built before the transcription process, as we highlighted before. A possible solution to avoid this mistake is work with both strands filled in, or clarify the purpose of this activity. After that, the students did the transcription of the two ‘genic sequences’ in each group. For that, they had to discuss some questions, such as: how is a gene recognised? Where does the transcription start? Who does the RNA polymerisation? The kit parts were handled at the same time, which provided an active and dynamic experience. The splicing process was also discussed. We found some difficulties to adapt this complex process to our material, however, we observed that some important concepts were better under stood, as exon, intron and spliceosome. 10 L. F. SILVEIRA ET AL. After the last activity described above, the first theoretical pause was conducted. The dynamic may contain this step or not, it can be a choice of the professor. In our context, this step was important to verify the remaining doubts and to put all groups in the same level of understanding. We do not advise long theoretical hours with excess of content in this step, because it can take the focus off the activity and discourage students. The last process we worked on was the translation. The material handling allowed a tridimensional experience to know about the protein synthesis and its steps: coupling of the initiation complex, pairing between codon and anticodon, tRNA positioning at ribosome sites, and protein formation. The sequence of events and how the process evolves to build a protein were discussed by the students with the guidance of the tutor. The students tried to simulate the process with the elements available in the kit, and often they noticed inconsistencies in their thinking processes, these situations stimulated the discussion and the trial and error learning. It is important to mention that the script with check questions was essential to ensure that all groups had seen the same points and to situate the students regarding the learning aims. With this material, they knew when and what they had to learn. After a second theoretical pause, we finished the class and in the subsequent class we conducted a brief conclusion moment. Each group read and answered the problem, sharing the experience with colleagues. Knowledge assessment Students answered four general questions about the central dogma, transcription and translation of the DNA and the protein diversity before starting the dynamic and after the conclusion (last step of the dynamic). Their answers were analysed in two ways: counting the right and wrong answers across the whole group in the pre-questionnaire (PreQ) and post-questionnaire (PostQ) (Figure 6), Figure 6. Evaluation of the answers to each question in the pre and post-questionnaires. Note: Q1: Question 1- Description of the Central Dogma; Q2: Question 2 – Definition of the transcription process; Q3: Question 3 – Definition of the translation process; Q4: Question 4 – Description of the processes responsible for protein variability. PreQ: pre-questionnaire; PostQ: post-questionnaire. Changes in the percentage of correct and wrong answers, comparing pre and post questionnaires, were not statistically significant in any question (p > 0.05). JOURNAL OF BIOLOGICAL EDUCATION 11 Figure 7. Changes in students’ answers to each question in the pre and post-questionnaires. Note: Blank answers were not included in these analyzes. In ‘wrong group’ are included students who answered correctly with minor or serious conceptual mistake. Q1: Question 1- Description of the Central Dogma; Q2: Question 2 – Definition of the transcription process; Q3: Question 3 – Definition of the translation process; Q4: Question 4 – Description of the processes responsible for protein variability. PreQ: pre-questionnaire; PostQ: post-questionnaire; Conclusion: results from post-questionnaire. and also in a paired way, considering the changes in the students’ answers from the PreQ to the PostQ (Figure 7). Firstly, they were requested to describe the way from DNA to protein (Q1). Initially, 71% of the answers were totally correct and this percentage increased by 10% after the dynamic (Figure 6). Approximately 33% of the students who provided a wrong answer remained with erroneous conceptions about the central dogma (Figure 7). Then, the students were asked to describe the transcription process (Q2). Before the dynamic, 43% of the students properly described the process, this percentage increased to 57% after the dynamic (Figure 6). Considering those who initially answered in a wrong way (PreQ), 45.5% of them changed to a correct answer in the PostQ (Figure 7). In the next question, the students were asked to describe the translation process (Q3). Absolutely correct definitions increased from 48% to 67% after the dynamic. Approximately 56% of the students who initially provided wrong definitions changed to right definitions after the dynamic (Figure 7). Regarding the fourth question (Q4), it was possible to verify that the students had no initial knowledge about the mechanisms responsible by protein variety, since nobody provided totally correct answers (Figure 6). Even after the dynamic, only 10% provided totally correct answers (Figure 7). We had expected answers including alternative splicing and its consequences for the protein variety. Perhaps, the students had focussed on the complexity of the splicing process and did not think about the next step, that is, the consequence of the splicing – protein variability. It can be 12 L. F. SILVEIRA ET AL. due to the practice itself, or the stimulus provided by the professor and tutors were not sufficient to clarify this point. In a general way, it was possible to associate the dynamic with improved knowledge of DNA transcription and translation; however, the increase in the correct answers proportion in the postquestionnaire was not significant. Some factors can be associated to this result. Transcription and translation of DNA are difficult contents, and it is possible that the students may need other strategies besides the dynamic to learn. For most of these students, this was the first experience with an active teaching strategy and because it is new, their teaching potential may not have been explored properly by the students and even the tutors. Other possibility is that the importance of the questionnaires for the students was not clear and they did not answer so seriously. The short time they spent responding the questionnaires suggests a lack of commitment with this task. Regarding these results, there is other important observation to discuss. As seen in the (Figure 7), a small percentage of students who had answered correctly in the pre-questionnaire, answered the same question incorrectly in the post-questionnaire. This pattern was observed in the first three questions. We investigated the possible causes for this situation, and we noticed that these students had answered the pre-questionnaire in a succinct way, but, in the post-questionnaire, they answered the same question in a more elaborate way, with more details and with minor conceptual mistake. Thus, all these students that answered initially in a totally correct way, answered the same question correctly with a minor conceptual mistake after the dynamic. Possibly, more information was added to the initial knowledge of these students, however, there was not enough time and/or stimulus to connect this information and to develop a more complex answer totally correct. It would be interesting to compare these results with another independent experience (a traditional class experience, for example), in order to evaluate the efficacy of the dynamic compared to other methodologies. Finally, regarding the last question of the PreQ, 38% of the students expected to have difficulties with these contents, 19% expected to have a bit of difficult, while 43% believed they would have no difficulties. These data might reflect the academic heterogeneity of these students, since approxi mately half of them expected to have difficulties, while the other half did not expect it. Actually, in this group, we had some repeating students, students coming from private schools and from public schools. Unfortunately, in Brazil, there are a huge discrepancy between private and public schools, and this situation contributes to the basic formation of the students. In the PostQ, there were two additional questions. In the first question, students described concepts that became clear or less confusing after the dynamic, if there were previously misunder stood or unclear concepts about the contents. The second one asked for positive and negative Figure 8. Word cloud generated from the students’ answers to the open questions of the post-questionnaire. Note: The cloud on the left refers to the concepts clarified after the dynamic according to the students. The cloud on the right refers to the positive aspects of the dynamic according to the students. JOURNAL OF BIOLOGICAL EDUCATION 13 aspects of the dynamic. We opted to show these results through a word cloud, in which words that appeared the most are in larger size, how it is possible see in the (Figure 8) Among the concepts clarified by the dynamic, splicing was the most mentioned. It can be due to the lack of explanation during the high school, despite the term appearing in textbooks. Basically, we did not have negative aspects mentioned by the students, and among the positive aspects, the words visualisation and playful were frequently mentioned. This reflects the purpose of the dynamic: learning these contents less abstractly and more actively. Educational implications Educational researches have sought to find teaching strategies that promote learning beyond memorisation. In this sense, active strategies have didactic aspects that can provide ways to achieve a more lasting learning, able to articulate with other knowledges. Molecular genetics is widely seen as a content that needs to be memorised to be learned. Our proposal is to make available to other professors and teachers a didactic strategy which brings some assumptions of active learning, without however, fitting into a well-known model of active learning. We developed this dynamic with a focus on undergraduate veterinary students and the skills derived from the contents of molecular genetics are of great importance for these students, since molecular approaches, such as recombinant DNA technology and molecular diagnostics, are, nowadays, common in clinical practice and also in research and development. Although the focus of the material was on the future veterinarian, it is easily adaptable to other courses, considering that the contents of molecular genetics are taught in many other graduate courses. Acknowledgements The authors would like to thank the veterinary medicine students for their enthusiastic participation. Disclosure statement No potential conflict of interest was reported by the authors. Funding This work had no financial support. ORCID Lucas Fagundes Silveira http://orcid.org/0000-0003-2444-395X Maíra Alexandre Perez http://orcid.org/0000-0003-2672-2389 Dandie Antunes Bozza http://orcid.org/0000-0002-6296-3991 http://orcid.org/0000-0002-1616-8225 Lupe Furtado-Alle Iris Hass http://orcid.org/0000-0003-4723-2178 Luciane Viater Tureck http://orcid.org/0000-0002-4200-1189 References Bonwell, C. C. J., and J. A. Eison 1991. “Active Learning: Creating Excitement in the Classroom”. ASHE-ERIC Higher Education Reports. Duncan, R. G., and B. J. Reiser. 2007. “Reasoning across Ontologically Distinct Levels: Students’ Understandings of Molecular Genetics.” Journal of Research in Science Teaching 44 (7): 938–959. doi:10.1002/tea.20186. Lewis, J., and U. Kattman. 2004. “Traits, Genes, Particles and Information: Re-visiting Students’ Understandings of Genetics.” International Journal of Science Education 26 (2): 195–206. doi:10.1080/0950069032000072782. 14 L. F. SILVEIRA ET AL. Marbach-Ad, G., and R. 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