Improving the learning experience in an undergraduate course on microbial metabolism by using an illustrated story
INTRODUCTION Metabolism is critical to the functioning of life. A working understanding of metabolism should thus be expected of life science professionals. However, both teaching and learning metabolism are inherently challenging. The topic is detail‐intensive, contains unfamiliar terminology, and is often accompanied by layers of regulation, thermodynamics, and math. Metabolism also has a stereotypically negative reputation among students and even some instructors. Negative emotions toward metabolism, like boredom, hopelessness, and anger, can exacerbate the challenge of helping students learn. , Competency with metabolism is often reduced to memorization, , leaving students unable to connect details to functional knowledge, , , , the ability to know when, why, and how details connect. We liken functional knowledge to understanding , or systems thinking skills. , , Functional knowledge is an important step towards “expert knowledge” or “mastery” where knowledge is organized in a contextually meaningful way, allowing for appropriate application of knowledge to specific situations. , , As educators, we need to make learning about metabolism engaging, interesting, enjoyable, motivating, and meaningful. Humans often desire, and might even be wired, to receive information via a narrative or story format. , , As such, storytelling could facilitate learning science, and it is less likely to exclude students given the familiar format. Storytelling has been reported to improve student engagement and enjoyment in a genetics course. An illustrated story also improved both knowledge and attitudes in several undergraduate biology courses enrolled by both majors and non‐majors. We hypothesized that nesting metabolic details within the familiar story framework of the hero's journey could provide an inviting context to address teaching and learning challenges. Specifically, we sought to (i) improve attitudes towards an important but traditionally unpopular topic and (ii) improve functional knowledge. Here we document the use of a visual story to teach microbial metabolism in an undergraduate lecture course. Our data, collected over four semesters, suggests that a relatively minimal implementation of a story can contribute to an enjoyable learning experience with possible improvements in performance on traditionally challenging questions that require functional knowledge. 

MATERIALS AND METHODS 2.1 The course and mode of instruction This study was performed under Indiana University IRB protocol #1902450239, “Functional knowledge through storytelling in M350 – Microbial physiology and biochemistry.” The study was performed in the undergraduate lecture course BIOL‐M 350 Microbial Physiology and Biochemistry in the Spring semesters of 2019, 2021, 2022, and 2023 at Indiana University, Bloomington. Students learned how microbes use networks of biochemical reactions (i.e., metabolism) to synthesize macromolecules, transform and use energy, and sense and adapt to their environment. The course explored different metabolic strategies that microbes use to survive and drew connections to biotechnology, the environment, and disease. The course mostly focused on Escherichia coli but included other bacteria, with less time devoted to archaea and eukaryotes. Lectures were 75 min twice per week. Most classes had at least one in‐class exercise. There were six homework assignments that included processing and interpreting mock data on growth and enzyme kinetics using Microsoft Excel, practicing algebraic skills, using online databases and tools, and interpreting primary literature. Students also completed three midterm exams and one cumulative final exam (Figure ). McKinlay was the sole instructor during the study. In 2019, the course had 14 students (3 female, 11 male) and met in person. In 2020, the study was paused while another instructor taught the course. In 2021, the course had 22 students (14 female, 8 male) and met online due to pandemic conditions. In 2022, the course had 15 students (7 female, 8 male) who were given the option to meet either in‐person or online at their discretion. Six students chose to attend all lectures online and three more students shifted to primarily online instruction about halfway through the semester. Although we do not present the data, there was a strongly significant correlation between online instruction and poor performance compared to performance by students who consistently attended in person in 2022. In 2023, the course had 13 students (9 female, 4 male) and met in person. 2.2 The story Although the story is about an E. coli bacterium, we wanted it to feel familiar. We thus exploited a “hero's journey” or “voyage and return” plotline, a basic plot thought to be broadly familiar and appealing. The hero's journey follows a protagonist through (i) a beginning in an ordinary world, (ii) a disruption or call to adventure, (iii) a journey from the familiar, (iv) a meeting with a mentor, (v) a series of trials or obstacles that builds to (vi) a climactic trial, and finally (vii) a return to the ordinary world. The story also has typical features of rising action, a climax, and a resolution. We avoided anthropomorphizing E. coli by presenting the story in the third person with the emotion conveyed through the voice of the narrator and the perilous situations encountered. The story follows a single E. coli protagonist cell during a cholera outbreak in Bangladesh and includes the metabolic strategies that E. coli and other microbes use to survive. E. coli began in the “ordinary world” of a human gut. Disruption, or the call to adventure, was introduced when Vibrio cholerae attacked the host and the bacterial flora. E. coli escaped as the diarrhetic symptoms manifested, expelling E. coli into a river. E. coli then faced a series of obstacles in river, biofilm, and sediment environments. Along the way, E. coli acquired new genes from another cell, akin to the mentor in the hero's journey. Ultimately, E. coli returned to the human gut where it used its new gene products in a final battle with V. cholerae . 2.3 Integration of the story with the course The lecture sequence was organized around the story. Each lecture typically began with a few slides featuring a chunk of the story and narrated by the instructor, before returning to a more traditional lecture. The story was referenced throughout a given lecture, with more of the story introduced as the lectures progressed. Students were exposed to the entire story multiple times over three parts of the course (Figure ). Part 1 featured a quick overview, then introduced the protagonist lecture‐by‐lecture as students learned about E. coli cell structure (Figure ). For Part 2, the course progressed through the entire story lecture‐by‐lecture, introducing the metabolic abilities of E. coli as it moved between different environments (Figure ). In Part 3, the entire storyline was revisited, but with an emphasis on the plot transitions and the regulatory mechanisms behind the physiological changes (Figure ). 2.4 Yearly variations In 2019, students were given an overview of the story about a month into the course during a lecture. The story was then used throughout the course. From 2021 to 2023, prior to the first class, students had access to a video of the story, originally developed for Indiana University's 2020 Science Fest public outreach event: www.youtube.com/watch?v=pNmaUP1egFg&t=1s . Most students watched the video before the course started or early in the course (Figure ). The story was then used from the first class onwards. 2.5 Surveys and other assessments Students' attitudes and performance were assessed using surveys, exam scores, and university‐mandated course evaluations. Assessments were performed by McKinlay. 2.5.1 Surveys Students were asked to fill out (i) an “impressions” survey and (ii) a pre‐post knowledge survey (supplementary information). Each survey was given twice, due once in week 4, and again in week 16 (Figure ). Each survey was available for 1 to 2 weeks. To encourage participation, participants were given a few bonus points towards their final grade. Each survey featured multiple choice and short written answer questions. Surveys received minor yearly modifications to address misinterpretations. Impressions survey Participation ranged from 85% to 100% across all years. The same version of the impressions survey was given around weeks 4 and 16. The impressions surveys were always completed online. There was no time‐limit other than meeting the deadline. Responses were anonymous but students were asked to create a unique identifier so that changes in attitudes could be ascertained. Some data were excluded due to inconsistent identifiers. The impressions survey tracked changes in attitudes by asking students to provide three “feeling” words to complete: (i) “Metabolism is…” and (ii) “Metabolism makes me feel…” Each response was assigned a score based on whether the responses were negative (score = −1), neutral (score = 0), or positive (score = 1). A list of all submitted words and how they were scored is in the supplementary material. Changes in attitudes were summed for each student and linked between week 4 and week 16 surveys using the anonymous identifiers by sum of week 16 scores – sum of week 4 scores. For example, three positive week 16 responses following three negative week 4 responses would be +3 − (−3) = +6. The impressions surveys also scored how students felt about their understanding of metabolism using: 0, totally lost; 1, losing ground; 2, I'll get it if I put more work in; 3, getting the hang of it; 4, highly confident. If students selected more than one category, the average was taken. Students were also asked to reflect on resources that they felt helped them learn. Students could enter anything, but they were also given suggestions (see supplementary materials), including “traditional lectures” and “lectures with storytelling.” In 2022 and 2023, “traditional lectures” was replaced with “lectures without storytelling” in case “traditional lectures” were misinterpreted as “in‐person lectures,” given that the course was taught online in 2021. Mentions of “lectures” without additional descriptors were conservatively assumed to not include storytelling. Pre‐post knowledge survey Participation ranged from 91% to 100% across all years. Students were randomly assigned one of two survey versions around week 4 (pre). Students then received the alternate version around week 16 (post). In 2019, students were given 10 min to complete knowledge surveys on paper during class. From 2021 to 2023, students were given 1–2 weeks to complete knowledge surveys online with a 10‐min time‐limit. Students were informed that full points were awarded for participation rather than correctness. Students were not told if their responses were correct. Responses were not anonymous at the time of completion to allow for performance tracking but responses were afterward anonymized for this paper. Each version of the knowledge survey asked similar questions but in a different format (e.g., one survey might ask for a short, written answer while the other would reframe the question in a multiple‐choice format). Seven questions were chosen to (i) span course content, (ii) address traditionally low‐scoring areas, and (iii) mostly assess functional knowledge (questions #1 and #7 did not assess functional knowledge). We assumed that questions tested functional knowledge if they required the application of specific details to a given situation. To assess changes in performance, we applied a 5‐point scheme: −2, a correct answer in week 4 was followed by an incorrect answer in week 16; −1, an incorrect answer was given on both pre‐ and post‐surveys; 0, correct on both pre and post surveys; 1, an incorrect answer in week 4 was partially correct in week 16, due to one part of a two‐part question being correct or if responses were ambiguous but showed some evidence of understanding; 2, a correct answer in week 16 followed an incorrect answer in week 4. Correct answers in week 4 followed by incorrect answers in week 16 were scored lower than those that were incorrect on both surveys to account for the possibility that the story was having a negative impact on performance, although other factors could explain worse scores, such as correct answers in week 4 resulting from guessing. 2.5.2 Other assessments Comparative exam performance Performance was also assessed by comparing (i) unscaled cumulative final exam scores and (ii) scores on three traditionally low‐scoring final exam questions that tested functional knowledge and that were administered across years with and without the story (2015–2018 vs. 2019–2023; Figure ). Other than using the story, course content, assignments, and exam formats were similar from 2015 to 2023. Enrollments prior to the use of the story were 2015: 33 (10 female, 23 male), 2016: 25 (11 female, 14 male), 2017: 23 (7 female, 16 male), 2018: 17 (8 female, 9 male). McKinlay was the sole instructor in all years. Course evaluations University‐mandated course evaluations during the four semesters of the study were also examined for mentioning the story in the comments section (Figure ). 

The course and mode of instruction This study was performed under Indiana University IRB protocol #1902450239, “Functional knowledge through storytelling in M350 – Microbial physiology and biochemistry.” The study was performed in the undergraduate lecture course BIOL‐M 350 Microbial Physiology and Biochemistry in the Spring semesters of 2019, 2021, 2022, and 2023 at Indiana University, Bloomington. Students learned how microbes use networks of biochemical reactions (i.e., metabolism) to synthesize macromolecules, transform and use energy, and sense and adapt to their environment. The course explored different metabolic strategies that microbes use to survive and drew connections to biotechnology, the environment, and disease. The course mostly focused on Escherichia coli but included other bacteria, with less time devoted to archaea and eukaryotes. Lectures were 75 min twice per week. Most classes had at least one in‐class exercise. There were six homework assignments that included processing and interpreting mock data on growth and enzyme kinetics using Microsoft Excel, practicing algebraic skills, using online databases and tools, and interpreting primary literature. Students also completed three midterm exams and one cumulative final exam (Figure ). McKinlay was the sole instructor during the study. In 2019, the course had 14 students (3 female, 11 male) and met in person. In 2020, the study was paused while another instructor taught the course. In 2021, the course had 22 students (14 female, 8 male) and met online due to pandemic conditions. In 2022, the course had 15 students (7 female, 8 male) who were given the option to meet either in‐person or online at their discretion. Six students chose to attend all lectures online and three more students shifted to primarily online instruction about halfway through the semester. Although we do not present the data, there was a strongly significant correlation between online instruction and poor performance compared to performance by students who consistently attended in person in 2022. In 2023, the course had 13 students (9 female, 4 male) and met in person. 

The story Although the story is about an E. coli bacterium, we wanted it to feel familiar. We thus exploited a “hero's journey” or “voyage and return” plotline, a basic plot thought to be broadly familiar and appealing. The hero's journey follows a protagonist through (i) a beginning in an ordinary world, (ii) a disruption or call to adventure, (iii) a journey from the familiar, (iv) a meeting with a mentor, (v) a series of trials or obstacles that builds to (vi) a climactic trial, and finally (vii) a return to the ordinary world. The story also has typical features of rising action, a climax, and a resolution. We avoided anthropomorphizing E. coli by presenting the story in the third person with the emotion conveyed through the voice of the narrator and the perilous situations encountered. The story follows a single E. coli protagonist cell during a cholera outbreak in Bangladesh and includes the metabolic strategies that E. coli and other microbes use to survive. E. coli began in the “ordinary world” of a human gut. Disruption, or the call to adventure, was introduced when Vibrio cholerae attacked the host and the bacterial flora. E. coli escaped as the diarrhetic symptoms manifested, expelling E. coli into a river. E. coli then faced a series of obstacles in river, biofilm, and sediment environments. Along the way, E. coli acquired new genes from another cell, akin to the mentor in the hero's journey. Ultimately, E. coli returned to the human gut where it used its new gene products in a final battle with V. cholerae . 

Integration of the story with the course The lecture sequence was organized around the story. Each lecture typically began with a few slides featuring a chunk of the story and narrated by the instructor, before returning to a more traditional lecture. The story was referenced throughout a given lecture, with more of the story introduced as the lectures progressed. Students were exposed to the entire story multiple times over three parts of the course (Figure ). Part 1 featured a quick overview, then introduced the protagonist lecture‐by‐lecture as students learned about E. coli cell structure (Figure ). For Part 2, the course progressed through the entire story lecture‐by‐lecture, introducing the metabolic abilities of E. coli as it moved between different environments (Figure ). In Part 3, the entire storyline was revisited, but with an emphasis on the plot transitions and the regulatory mechanisms behind the physiological changes (Figure ). 

Yearly variations In 2019, students were given an overview of the story about a month into the course during a lecture. The story was then used throughout the course. From 2021 to 2023, prior to the first class, students had access to a video of the story, originally developed for Indiana University's 2020 Science Fest public outreach event: www.youtube.com/watch?v=pNmaUP1egFg&t=1s . Most students watched the video before the course started or early in the course (Figure ). The story was then used from the first class onwards. 

Surveys and other assessments Students' attitudes and performance were assessed using surveys, exam scores, and university‐mandated course evaluations. Assessments were performed by McKinlay. 2.5.1 Surveys Students were asked to fill out (i) an “impressions” survey and (ii) a pre‐post knowledge survey (supplementary information). Each survey was given twice, due once in week 4, and again in week 16 (Figure ). Each survey was available for 1 to 2 weeks. To encourage participation, participants were given a few bonus points towards their final grade. Each survey featured multiple choice and short written answer questions. Surveys received minor yearly modifications to address misinterpretations. Impressions survey Participation ranged from 85% to 100% across all years. The same version of the impressions survey was given around weeks 4 and 16. The impressions surveys were always completed online. There was no time‐limit other than meeting the deadline. Responses were anonymous but students were asked to create a unique identifier so that changes in attitudes could be ascertained. Some data were excluded due to inconsistent identifiers. The impressions survey tracked changes in attitudes by asking students to provide three “feeling” words to complete: (i) “Metabolism is…” and (ii) “Metabolism makes me feel…” Each response was assigned a score based on whether the responses were negative (score = −1), neutral (score = 0), or positive (score = 1). A list of all submitted words and how they were scored is in the supplementary material. Changes in attitudes were summed for each student and linked between week 4 and week 16 surveys using the anonymous identifiers by sum of week 16 scores – sum of week 4 scores. For example, three positive week 16 responses following three negative week 4 responses would be +3 − (−3) = +6. The impressions surveys also scored how students felt about their understanding of metabolism using: 0, totally lost; 1, losing ground; 2, I'll get it if I put more work in; 3, getting the hang of it; 4, highly confident. If students selected more than one category, the average was taken. Students were also asked to reflect on resources that they felt helped them learn. Students could enter anything, but they were also given suggestions (see supplementary materials), including “traditional lectures” and “lectures with storytelling.” In 2022 and 2023, “traditional lectures” was replaced with “lectures without storytelling” in case “traditional lectures” were misinterpreted as “in‐person lectures,” given that the course was taught online in 2021. Mentions of “lectures” without additional descriptors were conservatively assumed to not include storytelling. Pre‐post knowledge survey Participation ranged from 91% to 100% across all years. Students were randomly assigned one of two survey versions around week 4 (pre). Students then received the alternate version around week 16 (post). In 2019, students were given 10 min to complete knowledge surveys on paper during class. From 2021 to 2023, students were given 1–2 weeks to complete knowledge surveys online with a 10‐min time‐limit. Students were informed that full points were awarded for participation rather than correctness. Students were not told if their responses were correct. Responses were not anonymous at the time of completion to allow for performance tracking but responses were afterward anonymized for this paper. Each version of the knowledge survey asked similar questions but in a different format (e.g., one survey might ask for a short, written answer while the other would reframe the question in a multiple‐choice format). Seven questions were chosen to (i) span course content, (ii) address traditionally low‐scoring areas, and (iii) mostly assess functional knowledge (questions #1 and #7 did not assess functional knowledge). We assumed that questions tested functional knowledge if they required the application of specific details to a given situation. To assess changes in performance, we applied a 5‐point scheme: −2, a correct answer in week 4 was followed by an incorrect answer in week 16; −1, an incorrect answer was given on both pre‐ and post‐surveys; 0, correct on both pre and post surveys; 1, an incorrect answer in week 4 was partially correct in week 16, due to one part of a two‐part question being correct or if responses were ambiguous but showed some evidence of understanding; 2, a correct answer in week 16 followed an incorrect answer in week 4. Correct answers in week 4 followed by incorrect answers in week 16 were scored lower than those that were incorrect on both surveys to account for the possibility that the story was having a negative impact on performance, although other factors could explain worse scores, such as correct answers in week 4 resulting from guessing. 2.5.2 Other assessments Comparative exam performance Performance was also assessed by comparing (i) unscaled cumulative final exam scores and (ii) scores on three traditionally low‐scoring final exam questions that tested functional knowledge and that were administered across years with and without the story (2015–2018 vs. 2019–2023; Figure ). Other than using the story, course content, assignments, and exam formats were similar from 2015 to 2023. Enrollments prior to the use of the story were 2015: 33 (10 female, 23 male), 2016: 25 (11 female, 14 male), 2017: 23 (7 female, 16 male), 2018: 17 (8 female, 9 male). McKinlay was the sole instructor in all years. Course evaluations University‐mandated course evaluations during the four semesters of the study were also examined for mentioning the story in the comments section (Figure ). 

Surveys Students were asked to fill out (i) an “impressions” survey and (ii) a pre‐post knowledge survey (supplementary information). Each survey was given twice, due once in week 4, and again in week 16 (Figure ). Each survey was available for 1 to 2 weeks. To encourage participation, participants were given a few bonus points towards their final grade. Each survey featured multiple choice and short written answer questions. Surveys received minor yearly modifications to address misinterpretations. Impressions survey Participation ranged from 85% to 100% across all years. The same version of the impressions survey was given around weeks 4 and 16. The impressions surveys were always completed online. There was no time‐limit other than meeting the deadline. Responses were anonymous but students were asked to create a unique identifier so that changes in attitudes could be ascertained. Some data were excluded due to inconsistent identifiers. The impressions survey tracked changes in attitudes by asking students to provide three “feeling” words to complete: (i) “Metabolism is…” and (ii) “Metabolism makes me feel…” Each response was assigned a score based on whether the responses were negative (score = −1), neutral (score = 0), or positive (score = 1). A list of all submitted words and how they were scored is in the supplementary material. Changes in attitudes were summed for each student and linked between week 4 and week 16 surveys using the anonymous identifiers by sum of week 16 scores – sum of week 4 scores. For example, three positive week 16 responses following three negative week 4 responses would be +3 − (−3) = +6. The impressions surveys also scored how students felt about their understanding of metabolism using: 0, totally lost; 1, losing ground; 2, I'll get it if I put more work in; 3, getting the hang of it; 4, highly confident. If students selected more than one category, the average was taken. Students were also asked to reflect on resources that they felt helped them learn. Students could enter anything, but they were also given suggestions (see supplementary materials), including “traditional lectures” and “lectures with storytelling.” In 2022 and 2023, “traditional lectures” was replaced with “lectures without storytelling” in case “traditional lectures” were misinterpreted as “in‐person lectures,” given that the course was taught online in 2021. Mentions of “lectures” without additional descriptors were conservatively assumed to not include storytelling. Pre‐post knowledge survey Participation ranged from 91% to 100% across all years. Students were randomly assigned one of two survey versions around week 4 (pre). Students then received the alternate version around week 16 (post). In 2019, students were given 10 min to complete knowledge surveys on paper during class. From 2021 to 2023, students were given 1–2 weeks to complete knowledge surveys online with a 10‐min time‐limit. Students were informed that full points were awarded for participation rather than correctness. Students were not told if their responses were correct. Responses were not anonymous at the time of completion to allow for performance tracking but responses were afterward anonymized for this paper. Each version of the knowledge survey asked similar questions but in a different format (e.g., one survey might ask for a short, written answer while the other would reframe the question in a multiple‐choice format). Seven questions were chosen to (i) span course content, (ii) address traditionally low‐scoring areas, and (iii) mostly assess functional knowledge (questions #1 and #7 did not assess functional knowledge). We assumed that questions tested functional knowledge if they required the application of specific details to a given situation. To assess changes in performance, we applied a 5‐point scheme: −2, a correct answer in week 4 was followed by an incorrect answer in week 16; −1, an incorrect answer was given on both pre‐ and post‐surveys; 0, correct on both pre and post surveys; 1, an incorrect answer in week 4 was partially correct in week 16, due to one part of a two‐part question being correct or if responses were ambiguous but showed some evidence of understanding; 2, a correct answer in week 16 followed an incorrect answer in week 4. Correct answers in week 4 followed by incorrect answers in week 16 were scored lower than those that were incorrect on both surveys to account for the possibility that the story was having a negative impact on performance, although other factors could explain worse scores, such as correct answers in week 4 resulting from guessing. 

Participation ranged from 85% to 100% across all years. The same version of the impressions survey was given around weeks 4 and 16. The impressions surveys were always completed online. There was no time‐limit other than meeting the deadline. Responses were anonymous but students were asked to create a unique identifier so that changes in attitudes could be ascertained. Some data were excluded due to inconsistent identifiers. The impressions survey tracked changes in attitudes by asking students to provide three “feeling” words to complete: (i) “Metabolism is…” and (ii) “Metabolism makes me feel…” Each response was assigned a score based on whether the responses were negative (score = −1), neutral (score = 0), or positive (score = 1). A list of all submitted words and how they were scored is in the supplementary material. Changes in attitudes were summed for each student and linked between week 4 and week 16 surveys using the anonymous identifiers by sum of week 16 scores – sum of week 4 scores. For example, three positive week 16 responses following three negative week 4 responses would be +3 − (−3) = +6. The impressions surveys also scored how students felt about their understanding of metabolism using: 0, totally lost; 1, losing ground; 2, I'll get it if I put more work in; 3, getting the hang of it; 4, highly confident. If students selected more than one category, the average was taken. Students were also asked to reflect on resources that they felt helped them learn. Students could enter anything, but they were also given suggestions (see supplementary materials), including “traditional lectures” and “lectures with storytelling.” In 2022 and 2023, “traditional lectures” was replaced with “lectures without storytelling” in case “traditional lectures” were misinterpreted as “in‐person lectures,” given that the course was taught online in 2021. Mentions of “lectures” without additional descriptors were conservatively assumed to not include storytelling. 

Participation ranged from 91% to 100% across all years. Students were randomly assigned one of two survey versions around week 4 (pre). Students then received the alternate version around week 16 (post). In 2019, students were given 10 min to complete knowledge surveys on paper during class. From 2021 to 2023, students were given 1–2 weeks to complete knowledge surveys online with a 10‐min time‐limit. Students were informed that full points were awarded for participation rather than correctness. Students were not told if their responses were correct. Responses were not anonymous at the time of completion to allow for performance tracking but responses were afterward anonymized for this paper. Each version of the knowledge survey asked similar questions but in a different format (e.g., one survey might ask for a short, written answer while the other would reframe the question in a multiple‐choice format). Seven questions were chosen to (i) span course content, (ii) address traditionally low‐scoring areas, and (iii) mostly assess functional knowledge (questions #1 and #7 did not assess functional knowledge). We assumed that questions tested functional knowledge if they required the application of specific details to a given situation. To assess changes in performance, we applied a 5‐point scheme: −2, a correct answer in week 4 was followed by an incorrect answer in week 16; −1, an incorrect answer was given on both pre‐ and post‐surveys; 0, correct on both pre and post surveys; 1, an incorrect answer in week 4 was partially correct in week 16, due to one part of a two‐part question being correct or if responses were ambiguous but showed some evidence of understanding; 2, a correct answer in week 16 followed an incorrect answer in week 4. Correct answers in week 4 followed by incorrect answers in week 16 were scored lower than those that were incorrect on both surveys to account for the possibility that the story was having a negative impact on performance, although other factors could explain worse scores, such as correct answers in week 4 resulting from guessing. 

Other assessments Comparative exam performance Performance was also assessed by comparing (i) unscaled cumulative final exam scores and (ii) scores on three traditionally low‐scoring final exam questions that tested functional knowledge and that were administered across years with and without the story (2015–2018 vs. 2019–2023; Figure ). Other than using the story, course content, assignments, and exam formats were similar from 2015 to 2023. Enrollments prior to the use of the story were 2015: 33 (10 female, 23 male), 2016: 25 (11 female, 14 male), 2017: 23 (7 female, 16 male), 2018: 17 (8 female, 9 male). McKinlay was the sole instructor in all years. Course evaluations University‐mandated course evaluations during the four semesters of the study were also examined for mentioning the story in the comments section (Figure ). 

Performance was also assessed by comparing (i) unscaled cumulative final exam scores and (ii) scores on three traditionally low‐scoring final exam questions that tested functional knowledge and that were administered across years with and without the story (2015–2018 vs. 2019–2023; Figure ). Other than using the story, course content, assignments, and exam formats were similar from 2015 to 2023. Enrollments prior to the use of the story were 2015: 33 (10 female, 23 male), 2016: 25 (11 female, 14 male), 2017: 23 (7 female, 16 male), 2018: 17 (8 female, 9 male). McKinlay was the sole instructor in all years. 

University‐mandated course evaluations during the four semesters of the study were also examined for mentioning the story in the comments section (Figure ). 

RESULTS 3.1 Students indicated that the story improved their attitude towards metabolism One of the main goals of incorporating a story into lectures was to improve attitudes towards metabolism. The impressions survey scored words used to complete: (i) “Metabolism is…” and (ii) “Metabolism makes me feel…” Across all four years, responses associated with negative emotions decreased from week 4 to week 16 while responses associated with positive emotions increased (Figure ). In three of the four years, changes in impressions for “Metabolism is…” was significantly improved by about 1 point (Figure ). Changes in impressions for “Metabolism makes me feel…” were only significant in 2023 with an average improved attitude score of 2.7. Attitude changes could have been influenced by multiple factors. We therefore asked students to describe what contributed to their responses. We grouped responses into emergent themes (Figure ). The story, or storytelling, was directly mentioned in five responses across all years. However, other responses could indirectly include storytelling, such as the “way it is taught,” which was mentioned the most. This category was mostly associated with negative attitudes in week 4 but with positive attitudes in week 16. “Providing context” and “recognition of importance” were also associated with positive impressions and could include the use of the story. Factors that contributed to negative attitudes were also informative. Aside from “it's complex,” most negative attitudes can be linked directly or indirectly to the reputation of metabolism. For example, the frequent mentions of “the way it is taught” in a negative context in week 4 could be indicative of reputation. “Lack of prior exposure,” often came with descriptions of previous instructors who had moved through metabolism too quickly, perhaps implying to the students that the topic was just a burdensome necessity (such descriptions were also counted towards “the way it is taught”). Other categories suggest that negative attitudes can spread. For example, some respondents linked negative impressions to previous instructors, peers, or a general reputation. These contributions to metabolism's negative reputation illustrate the challenge that instructors face before they even meet their students. We also looked for spontaneous mentions of the story in the impressions surveys where students were asked how the course affected their lives outside of the classroom. Most responses fell into one of four categories (Figure ). The story, or storytelling, received seven mentions across all years, the fourth most common response. However, the story could have also contributed to more frequent statements involving “connections to daily life/the world around us” and “enjoyed class” (Figure ). Most students also filled out a university‐mandated course evaluation, where they could comment on what they liked most or least about the course and instructor. Positive mentions of the use of the story ranged from 13% of respondents in 2019 to 35% in 2022 (Figure ). There were no negative mentions. 3.2 The story might have had a positive impact on student performance Another goal in implementing the story was to help students contextualize information and achieve functional knowledge, or an understanding of how, when, and why details connect. 3.2.1 Student perceptions In all years, students thought that their understanding of metabolism improved between weeks 4–16 (Figure ). When these impressions of performance were ranked using a scoring scheme, the improvement was significant in all years (Figure ). Only one student, across all years, thought that their understanding of metabolism declined, excluding responses that could not be linked between weeks 4 and 16. Students were also asked to reflect on resources that they felt helped them learn. When ranked by the number of week 16 responses, lectures (both online and in person) with storytelling tied for #1 among items (Figure ). This ranking is likely conservative as we assumed that “lectures,” without additional descriptors, meant that students did not find the story to be helpful enough to mention. 3.2.2 Performance on the pre‐post knowledge survey We also tried to determine whether student perceptions agreed with performance metrics. One way that we assessed performance was with a pre‐post knowledge survey (supplementary information). The only consistent improvements across all years were on questions 4 and 7, although they were not always significant (Figure ). Question 4 tested functional knowledge by asking students to choose a suitable electron donor and/or acceptor for a given lifestyle. Question 7 dealt with the importance of oxygenic phototrophs and was not deemed to assess functional knowledge. For other questions, changes in performance were variable across years (Figure ). Questions 1, 2, and 5 had non‐significant changes in performance except for in 2023, where performance was significantly improved. Performance on question 3 was improved in 2019 but trended towards neutral in subsequent years. Performance on question 6 was close to neutral in all years. 3.2.3 Performance on final exam questions We also assessed performance by comparing final exams from 2015 to 2018 (pre‐story) and 2019, 2021 to 2023 (with story). There was no significant difference in overall final exam scores before and after implementing the story (Figure average: 77 ± 3% SD vs. 75 ± 5% SD; t ‐test p = 0.63). We also compared performance on three final exam questions that were deemed to assess functional knowledge. For example, students were asked to explain how E. coli could make ATP after one or more nutrients were exhausted. Each scenario could be answered independently with a short, written answer. There was no significant change in scores before versus after the implementation of the story on this question (Figure average: 57 ± 7% SD vs. 60 ± 8% SD; t ‐test p = 0.54). The other two questions were similar to knowledge survey questions 2 and 4: respectively, how can E. coli make ATP during growth on acetate and what compounds could an organism use as an electron donor or acceptor for a given lifestyle. For both questions, average performance was significantly higher after the implementation of the story (Figure average: 40 ± 16% SD vs. 62 ± 14% SD; t ‐test p = 0.09; Figure average: 65 ± 9% SD vs. 80 ± 8% SD; t ‐test p = 0.05). 

Students indicated that the story improved their attitude towards metabolism One of the main goals of incorporating a story into lectures was to improve attitudes towards metabolism. The impressions survey scored words used to complete: (i) “Metabolism is…” and (ii) “Metabolism makes me feel…” Across all four years, responses associated with negative emotions decreased from week 4 to week 16 while responses associated with positive emotions increased (Figure ). In three of the four years, changes in impressions for “Metabolism is…” was significantly improved by about 1 point (Figure ). Changes in impressions for “Metabolism makes me feel…” were only significant in 2023 with an average improved attitude score of 2.7. Attitude changes could have been influenced by multiple factors. We therefore asked students to describe what contributed to their responses. We grouped responses into emergent themes (Figure ). The story, or storytelling, was directly mentioned in five responses across all years. However, other responses could indirectly include storytelling, such as the “way it is taught,” which was mentioned the most. This category was mostly associated with negative attitudes in week 4 but with positive attitudes in week 16. “Providing context” and “recognition of importance” were also associated with positive impressions and could include the use of the story. Factors that contributed to negative attitudes were also informative. Aside from “it's complex,” most negative attitudes can be linked directly or indirectly to the reputation of metabolism. For example, the frequent mentions of “the way it is taught” in a negative context in week 4 could be indicative of reputation. “Lack of prior exposure,” often came with descriptions of previous instructors who had moved through metabolism too quickly, perhaps implying to the students that the topic was just a burdensome necessity (such descriptions were also counted towards “the way it is taught”). Other categories suggest that negative attitudes can spread. For example, some respondents linked negative impressions to previous instructors, peers, or a general reputation. These contributions to metabolism's negative reputation illustrate the challenge that instructors face before they even meet their students. We also looked for spontaneous mentions of the story in the impressions surveys where students were asked how the course affected their lives outside of the classroom. Most responses fell into one of four categories (Figure ). The story, or storytelling, received seven mentions across all years, the fourth most common response. However, the story could have also contributed to more frequent statements involving “connections to daily life/the world around us” and “enjoyed class” (Figure ). Most students also filled out a university‐mandated course evaluation, where they could comment on what they liked most or least about the course and instructor. Positive mentions of the use of the story ranged from 13% of respondents in 2019 to 35% in 2022 (Figure ). There were no negative mentions. 

The story might have had a positive impact on student performance Another goal in implementing the story was to help students contextualize information and achieve functional knowledge, or an understanding of how, when, and why details connect. 3.2.1 Student perceptions In all years, students thought that their understanding of metabolism improved between weeks 4–16 (Figure ). When these impressions of performance were ranked using a scoring scheme, the improvement was significant in all years (Figure ). Only one student, across all years, thought that their understanding of metabolism declined, excluding responses that could not be linked between weeks 4 and 16. Students were also asked to reflect on resources that they felt helped them learn. When ranked by the number of week 16 responses, lectures (both online and in person) with storytelling tied for #1 among items (Figure ). This ranking is likely conservative as we assumed that “lectures,” without additional descriptors, meant that students did not find the story to be helpful enough to mention. 3.2.2 Performance on the pre‐post knowledge survey We also tried to determine whether student perceptions agreed with performance metrics. One way that we assessed performance was with a pre‐post knowledge survey (supplementary information). The only consistent improvements across all years were on questions 4 and 7, although they were not always significant (Figure ). Question 4 tested functional knowledge by asking students to choose a suitable electron donor and/or acceptor for a given lifestyle. Question 7 dealt with the importance of oxygenic phototrophs and was not deemed to assess functional knowledge. For other questions, changes in performance were variable across years (Figure ). Questions 1, 2, and 5 had non‐significant changes in performance except for in 2023, where performance was significantly improved. Performance on question 3 was improved in 2019 but trended towards neutral in subsequent years. Performance on question 6 was close to neutral in all years. 3.2.3 Performance on final exam questions We also assessed performance by comparing final exams from 2015 to 2018 (pre‐story) and 2019, 2021 to 2023 (with story). There was no significant difference in overall final exam scores before and after implementing the story (Figure average: 77 ± 3% SD vs. 75 ± 5% SD; t ‐test p = 0.63). We also compared performance on three final exam questions that were deemed to assess functional knowledge. For example, students were asked to explain how E. coli could make ATP after one or more nutrients were exhausted. Each scenario could be answered independently with a short, written answer. There was no significant change in scores before versus after the implementation of the story on this question (Figure average: 57 ± 7% SD vs. 60 ± 8% SD; t ‐test p = 0.54). The other two questions were similar to knowledge survey questions 2 and 4: respectively, how can E. coli make ATP during growth on acetate and what compounds could an organism use as an electron donor or acceptor for a given lifestyle. For both questions, average performance was significantly higher after the implementation of the story (Figure average: 40 ± 16% SD vs. 62 ± 14% SD; t ‐test p = 0.09; Figure average: 65 ± 9% SD vs. 80 ± 8% SD; t ‐test p = 0.05). 

Student perceptions In all years, students thought that their understanding of metabolism improved between weeks 4–16 (Figure ). When these impressions of performance were ranked using a scoring scheme, the improvement was significant in all years (Figure ). Only one student, across all years, thought that their understanding of metabolism declined, excluding responses that could not be linked between weeks 4 and 16. Students were also asked to reflect on resources that they felt helped them learn. When ranked by the number of week 16 responses, lectures (both online and in person) with storytelling tied for #1 among items (Figure ). This ranking is likely conservative as we assumed that “lectures,” without additional descriptors, meant that students did not find the story to be helpful enough to mention. 

Performance on the pre‐post knowledge survey We also tried to determine whether student perceptions agreed with performance metrics. One way that we assessed performance was with a pre‐post knowledge survey (supplementary information). The only consistent improvements across all years were on questions 4 and 7, although they were not always significant (Figure ). Question 4 tested functional knowledge by asking students to choose a suitable electron donor and/or acceptor for a given lifestyle. Question 7 dealt with the importance of oxygenic phototrophs and was not deemed to assess functional knowledge. For other questions, changes in performance were variable across years (Figure ). Questions 1, 2, and 5 had non‐significant changes in performance except for in 2023, where performance was significantly improved. Performance on question 3 was improved in 2019 but trended towards neutral in subsequent years. Performance on question 6 was close to neutral in all years. 

Performance on final exam questions We also assessed performance by comparing final exams from 2015 to 2018 (pre‐story) and 2019, 2021 to 2023 (with story). There was no significant difference in overall final exam scores before and after implementing the story (Figure average: 77 ± 3% SD vs. 75 ± 5% SD; t ‐test p = 0.63). We also compared performance on three final exam questions that were deemed to assess functional knowledge. For example, students were asked to explain how E. coli could make ATP after one or more nutrients were exhausted. Each scenario could be answered independently with a short, written answer. There was no significant change in scores before versus after the implementation of the story on this question (Figure average: 57 ± 7% SD vs. 60 ± 8% SD; t ‐test p = 0.54). The other two questions were similar to knowledge survey questions 2 and 4: respectively, how can E. coli make ATP during growth on acetate and what compounds could an organism use as an electron donor or acceptor for a given lifestyle. For both questions, average performance was significantly higher after the implementation of the story (Figure average: 40 ± 16% SD vs. 62 ± 14% SD; t ‐test p = 0.09; Figure average: 65 ± 9% SD vs. 80 ± 8% SD; t ‐test p = 0.05). 

DISCUSSION 4.1 Summary and limitations We implemented an illustrated story in an undergraduate course on bacterial metabolism with the goals of improving (i) student attitudes towards an important but unpopular subject and (ii) functional knowledge of detail‐intensive subject matter. Our results suggest that a few minutes of storytelling every lecture could have contributed to improved attitudes towards metabolism. Students also felt that their understanding of metabolism improved, and most noted lectures that included the story as a contributing factor. Actual performance metrics suggested that the story could have contributed to improved performance on some questions that required functional knowledge. The positive effects on student attitudes were encouraging, but could have also been influenced by other factors, in addition to the story. We cannot attribute all attitude changes to the story because our surveys were not conducted prior to the implementation of storytelling. Since 2012, M350 was consistently reviewed positively by students in university‐mandated course evaluations, so it is possible that attitudes also improved over the semester in years prior to using the story. Other pre‐existing aspects of the course that could have also contributed to improved attitudes include exercises with practical skills, emphasis on function over memorization, and the use of humor. We are encouraged by the improved performance on some questions that tested functional knowledge (Figure ). The story was the only major change introduced after 2018. Since the story transitioned E. coli between different environments, it would make sense that the story could have helped some students contextualize knowledge to better address questions on energy transformation in different environments. Other factors could have also contributed to improved performance. For example, the instructor had taught the course since 2012 and made minor yearly adjustments to lectures where students commonly struggled. Overall, any performance impact from storytelling was relatively small, limited to a few kinds of questions (Figure ). It is possible that the story was minimally impactful because M350 did not have prior widespread student performance issues. Storytelling, or other creative interventions, might be more impactful in courses with pre‐existing performance concerns. We can also confidently say that storytelling did not harm learning. Year‐to‐year survey responses and scores were generally consistent despite a small sample size and the impacts of the pandemic on the mode of instruction and student mental and physical health. Thus, storytelling or other interventions that suit an instructor's academic and creative interests could have acceptable, if not worthwhile, learning outcomes. 4.2 Recommendations and resources Our main goal was to provide an enjoyable and familiar framework to help students contextualize details. Positive emotions should benefit learning whereas negative emotions are generally detrimental. Thus, even a movement towards neutral opinions of metabolism could benefit learning. Whereas enjoyment can improve the classroom experience, enjoyment itself is not necessarily a good predictor of performance. However, hope is a good indicator of student performance. An initial encounter with a mountain of metabolic details could conceivably trigger hopelessness or self‐doubt. By providing a more familiar avenue to engage with the material, a story could give some students more hope for a successful course experience. When students have hope or elevated expectations for success, they can also be more motivated. Storytelling could give course material intrinsic value, where students gain satisfaction from the course independent of their performance. If students are motivated to attend and engage, then they are more likely to approach mastery, which comes with further satisfaction (attainment value). We also suspect that it was beneficial to cover the story multiple times throughout the course (Figure ). Revisiting a story could enforce spaced repetition, which can improve learning. Our actual implementation of storytelling was less involved than we originally envisioned. Instead of restructuring lectures around the story, existing lectures were simply reordered to match the story chronology and story slides only took a few minutes from each lecture. A more extensive integration of a story into the course is thus possible but could require substantial effort, even with the materials available. A potential area for improving the use of a story would be to explicitly condition students to use the story to contextualize content and then apply that contextualization to new situations. , For example, some exam questions implicitly required students to transfer knowledge to new situations by describing analogous situations to those in the story. Perhaps better performance would result if the question presented situations from the story itself or if students were directed to practice transferring knowledge in exercises prior to exams. With this manuscript, we also offer existing and upcoming resources (e.g., illustrations, videos, comic books) that could be integrated with various microbiology courses. Users are encouraged to explore additional applications of the materials such as a choose‐your‐own‐adventure interactive slide deck. , 

Summary and limitations We implemented an illustrated story in an undergraduate course on bacterial metabolism with the goals of improving (i) student attitudes towards an important but unpopular subject and (ii) functional knowledge of detail‐intensive subject matter. Our results suggest that a few minutes of storytelling every lecture could have contributed to improved attitudes towards metabolism. Students also felt that their understanding of metabolism improved, and most noted lectures that included the story as a contributing factor. Actual performance metrics suggested that the story could have contributed to improved performance on some questions that required functional knowledge. The positive effects on student attitudes were encouraging, but could have also been influenced by other factors, in addition to the story. We cannot attribute all attitude changes to the story because our surveys were not conducted prior to the implementation of storytelling. Since 2012, M350 was consistently reviewed positively by students in university‐mandated course evaluations, so it is possible that attitudes also improved over the semester in years prior to using the story. Other pre‐existing aspects of the course that could have also contributed to improved attitudes include exercises with practical skills, emphasis on function over memorization, and the use of humor. We are encouraged by the improved performance on some questions that tested functional knowledge (Figure ). The story was the only major change introduced after 2018. Since the story transitioned E. coli between different environments, it would make sense that the story could have helped some students contextualize knowledge to better address questions on energy transformation in different environments. Other factors could have also contributed to improved performance. For example, the instructor had taught the course since 2012 and made minor yearly adjustments to lectures where students commonly struggled. Overall, any performance impact from storytelling was relatively small, limited to a few kinds of questions (Figure ). It is possible that the story was minimally impactful because M350 did not have prior widespread student performance issues. Storytelling, or other creative interventions, might be more impactful in courses with pre‐existing performance concerns. We can also confidently say that storytelling did not harm learning. Year‐to‐year survey responses and scores were generally consistent despite a small sample size and the impacts of the pandemic on the mode of instruction and student mental and physical health. Thus, storytelling or other interventions that suit an instructor's academic and creative interests could have acceptable, if not worthwhile, learning outcomes. 

Recommendations and resources Our main goal was to provide an enjoyable and familiar framework to help students contextualize details. Positive emotions should benefit learning whereas negative emotions are generally detrimental. Thus, even a movement towards neutral opinions of metabolism could benefit learning. Whereas enjoyment can improve the classroom experience, enjoyment itself is not necessarily a good predictor of performance. However, hope is a good indicator of student performance. An initial encounter with a mountain of metabolic details could conceivably trigger hopelessness or self‐doubt. By providing a more familiar avenue to engage with the material, a story could give some students more hope for a successful course experience. When students have hope or elevated expectations for success, they can also be more motivated. Storytelling could give course material intrinsic value, where students gain satisfaction from the course independent of their performance. If students are motivated to attend and engage, then they are more likely to approach mastery, which comes with further satisfaction (attainment value). We also suspect that it was beneficial to cover the story multiple times throughout the course (Figure ). Revisiting a story could enforce spaced repetition, which can improve learning. Our actual implementation of storytelling was less involved than we originally envisioned. Instead of restructuring lectures around the story, existing lectures were simply reordered to match the story chronology and story slides only took a few minutes from each lecture. A more extensive integration of a story into the course is thus possible but could require substantial effort, even with the materials available. A potential area for improving the use of a story would be to explicitly condition students to use the story to contextualize content and then apply that contextualization to new situations. , For example, some exam questions implicitly required students to transfer knowledge to new situations by describing analogous situations to those in the story. Perhaps better performance would result if the question presented situations from the story itself or if students were directed to practice transferring knowledge in exercises prior to exams. With this manuscript, we also offer existing and upcoming resources (e.g., illustrations, videos, comic books) that could be integrated with various microbiology courses. Users are encouraged to explore additional applications of the materials such as a choose‐your‐own‐adventure interactive slide deck. , 

This work was supported by the National Science Foundation CAREER award MCB‐1749489. 

The authors declare that there is no conflict of interest. 

Data S1 Supporting Information. 

