Energy Connections and Misconnections across Chemistry and Biology

Visual representations of energy and chemical bonding in biology and chemistry textbooks: A case study of ATP hydrolysis

Energy is a crosscutting concept in science, but college students often perceive a mismatch between how their biology and chemistry courses discuss the topic. The challenge of reconciling these disciplinary differences can promote faulty reasoning-for example, biology students often develop the incorrect idea that breaking bonds is exothermic and releases energy. We hypothesize that one source of this perceived mismatch is that biology and chemistry textbooks use different visual representations of bond breaking and formation. We analyzed figures of ATP hydrolysis from 12 college-level introductory biology textbooks and coded each figure for its representation of energy, bond formation, and bond breaking. For comparison, we analyzed figures from six college-level introductory chemistry textbooks. We found that the majority (70%) of biology textbook figures presented ATP hydrolysis in the form "one reactant → multiple products" and "more bonds in reactants → fewer bonds in products". In contrast, chemistry textbook figures of the form "one reactant → multiple products" and "more bonds → fewer bonds" were predominantly endothermic reactions, which directly contradicts the exothermic nature of ATP hydrolysis. We hypothesize that these visual inconsistencies may be a contributing factor to student struggles in constructing a coherent mental model of energy and bonding.

Student perceptions of the usefulness of core concepts when reasoning in physiology

Research shows that when students use core concepts to guide their reasoning, they are able to construct more accurate, mechanistic explanations. However, there is scant research exploring student's perceptions of the usefulness of core concepts. Knowing students' perceptions could be influential in encouraging faculty to adopt core concept teaching strategies. In this study, we investigated how students perceive the usefulness of using the physiology core concepts to guide their reasoning. We collected the perceptions of undergraduate science majors who had completed Introductory Biology II, which was taught using a subset of physiology core concepts. Eleven student volunteers were interviewed using a semistructured protocol, and 22 students provided end-of-semester reflections. Using a constant comparative method, we identified four emergent themes in students' perceptions: core concepts guide reasoning, core concepts support reasoning and learning across topics and disciplines, core concepts build self-efficacy in reasoning, and drawn core concept tools visualize reasoning. These findings suggest that core concepts, when used as tools to reason with, help students explain rather than memorize physiological phenomena, thus supporting deeper learning and transfer of knowledge to novel contexts. We also found that drawn scaffolding tools play a critical role in helping students organize their thinking, making abstract systems more approachable and supporting mechanistic reasoning. This study is the first qualitative analysis examining students' perceptions of the role core concepts of physiology play in their learning and reasoning processes.NEW & NOTEWORTHY We explore how students perceive the benefits of using physiology core concepts in their learning. Students believe core concepts guide and strengthen their reasoning across topics, while improving their confidence in their ability to understand and reason. Our findings provide useful insights for educators on why and how they should integrate the core concepts of physiology into their teaching.

How students taking introductory biology experience the chemistry content

Student experiences learning chemistry have been well studied in chemistry courses but less so in biology courses. Chemistry concepts are foundational to introductory biology courses, and student experiences learning chemistry concepts may impact their overall course experiences and subsequent student outcomes. In this study, we asked undergraduate students enrolled in introductory biology courses at a public R1 institution an open-response question asking how their experiences learning chemistry topics affected their identities as biologists. We used thematic analysis to identify common ideas in their responses. We found that while almost half of student respondents cited learning chemistry as having positive impacts on their experiences learning biology, students who struggled with chemistry topics were significantly more likely to have negative experiences learning biology. We also found significant relationships between prior chemistry preparation, student background, and the likelihood of students struggling with chemistry and negative experiences learning biology. These findings emphasize the impact of learning specific content on student psychosocial metrics and suggest areas for biology educators to focus on to support learning and alleviate student stress in introductory biology.

Examining and Supporting Mechanistic Explanations Across Chemistry and Biology Courses

Causal mechanistic reasoning is a thinking strategy that can help students explain complex phenomena using core ideas commonly emphasized in separate undergraduate courses, as it requires students to identify underlying entities, unpack their relevant properties and interactions, and link them to construct mechanistic explanations. As a crossdisciplinary group of biologists, chemists, and teacher educators, we designed a scaffolded set of tasks that require content knowledge from biology and chemistry to construct nested hierarchical mechanistic explanations that span three scales (molecular, macromolecular, and cellular). We examined student explanations across seven introductory and upper-level biology and chemistry courses to determine how the construction of mechanistic explanations varied across courses and the relationship between the construction of mechanistic explanations at different scales. We found non-, partial, and complete mechanistic explanations in all courses and at each scale. Complete mechanistic explanation construction was lowest in introductory chemistry, about the same across biology and organic chemistry, and highest in biochemistry. Across tasks, the construction of a mechanistic explanation at a smaller scale was associated with constructing a mechanistic explanation for larger scales; however, the use of molecular scale disciplinary resources was only associated with complete mechanistic explanations at the macromolecular, not cellular scale.

Students explain evolution by natural selection differently for humans versus nonhuman animals

Evolution is foundational to understanding biology, yet learners at all stages have incomplete and incorrect ideas that persist beyond graduation. Contextual features of prompts (e.g., taxon of organism, acquisition vs. loss of traits, etc.) have been shown to influence both the learning process and the ideas students express in explanations of evolutionary processes. In this study, we compare students' explanations of natural selection for humans versus a nonhuman animal (cheetah) at different times during biology instruction. We found "taxon" to be a significant predictor of the content of students' explanations. Responses to "cheetah" prompts contained a larger number and diversity of key concepts (e.g., variation, heritability, differential reproduction) and fewer naïve ideas (e.g., need, adapt) when compared with responses to an isomorphic prompt containing "human" as the organism. Overall, instruction increased the prevalence of key concepts, reduced naïve ideas, and caused a modest reduction in differences due to taxon. Our findings suggest that the students are reasoning differently about evolutionary processes in humans as compared with nonhuman animals, and that targeted instruction may both increase students' facility with key concepts while reducing their susceptibility to contextual influences.

How Do Instructors Explain The Mechanism by which ATP Drives Unfavorable Processes?

Concerns regarding students' difficulties with the concept of energy date back to the 1970s. They become particularly apparent for systems involving adenosine triphosphate (ATP), which plays a central role in maintaining the nonequilibrium state of biological systems and in driving energetically unfavorable processes. One of the most well-documented misconceptions related to ATP is the idea that breaking bonds releases energy, when the opposite is true. This misconception is often attributed to language used in biology referring to the "high-energy bonds" in ATP. We interviewed chemistry, biology, and biochemistry instructors to learn how they think about and teach the mechanism(s) by which ATP is used as an energy source in biological systems. Across 15 interviews, we found that instructors relied primarily on two mechanisms to explain the role of ATP: 1) energy release, focused on ATP hydrolysis and bond energies; and/or 2) energy transfer, focused on phosphorylation and common intermediates. Many instructors shared negative and uncomfortable experiences related to teaching ATP and energy release. Based on these findings, we suggest instructional strategies that: 1) aim to ease the concerns expressed by introductory biology instructors, and 2) emphasize the role of ATP so as to support students' understanding of molecular mechanisms.

Student Perceptions of a Framework for Facilitating Transfer from Lessons to Exams, and the Relevance of This Framework to Published Lessons

A main goal of academic courses is to help students acquire knowledge and skills that they can transfer to multiple contexts. In this article, we (i) examine students' responses to test question templates (TQTs), a framework intended to facilitate transfer, and (ii) determine whether similar transfer-promoting strategies are commonly embedded in published biology lessons. In study 1, in surveys administered over several academic quarters, students consistently reported that TQTs helped them transfer course content to exams and the real world; that multiple (two to five) examples were generally needed to understand a given TQT, leading >40% students to create their own additional examples; and that TQTs would be helpful in other science courses. In study 2, among 100 peer-reviewed lessons published by CourseSource or the National Center for Case Study Teaching in Science (NCCSTS), less than 5% of lessons gave students advice about exams or helped students create additional practice problems. The latter finding is not meant as criticism of these excellent lessons, which are a boon to the biology education community. However, with TQT-like prescriptions generally absent from peer-reviewed lessons, biology instructors may wish to supplement the lessons with TQT-like strategies to explicitly connect the material to subsequent exams.

Using Systems and Systems Thinking to Unify Biology Education

As biological science rapidly generates new knowledge and novel approaches to address increasingly complex and integrative questions, biology educators face the challenge of teaching the next generation of biologists and citizens the skills and knowledge to enable them to keep pace with a dynamic field. Fundamentally, biology is the science of living systems. Not surprisingly, systems is a theme that pervades national reports on biology education reform. In this essay, we present systems as a unifying paradigm that provides a conceptual framework for all of biology and a way of thinking that connects and integrates concepts with practices. To translate the systems paradigm into concrete outcomes to support instruction and assessment in the classroom, we introduce the biology systems-thinking (BST) framework, which describes four levels of systems-thinking skills: 1) describing a system's structure and organization, 2) reasoning about relationships within the system, 3) reasoning about the system as a whole, and 4) analyzing how a system interacts with other systems. We conclude with a series of questions aimed at furthering conversations among biologists, biology education researchers, and biology instructors in the hopes of building support for the systems paradigm.

"Big Ideas" of Introductory Chemistry and Biology Courses and the Connections between Them

Introductory courses are often designed to cover a range of topics with the intent to offer students exposure to the given discipline as preparation to further their study in the same or related disciplines. Unfortunately, students in these courses are often presented with an overwhelming amount of information that may not support their formation of a usable coherent network of knowledge. In this study we conducted a mixed-method sequential exploratory study with students co-enrolled in General Chemistry II and Introductory Biology I to better understand what students perceived to be the "take-home" messages of these courses (i.e., core ideas) and the connections between these courses. We found that students identified a range of ideas from both courses; further analysis of students' explanations and reasoning revealed that, when students talked about their chemistry ideas, they were more likely to talk about them as having predictive and explanatory power in comparison with reasons provided for their biology big ideas. Furthermore, students identified a number of overlapping ideas between their chemistry and biology courses, such as interactions, reactions, and structures, which have the potential to be used as a starting place to support students building a more coherent network of knowledge.

Design and Implementation of a Tool to Assess Students' Understanding of Metabolic Pathways Dynamics and Regulation

Metabolic systems form the very foundation of life and as such are broadly taught in the molecular life sciences. Here, we describe the biochemistry educator community-based development and use of an assessment instrument designed to evaluate students' ideas about metabolic pathway dynamics and regulation in undergraduate biochemistry courses. Analysis of student responses showed that most students were able to interpret visual representations in an unfamiliar metabolic pathway and that many could make basic predictions about how the system would be expected to respond to changes. However, fewer students generated nuanced responses that accounted for both microscopic changes at the protein level and macroscopic changes in pathway product outputs. These findings identify some of the challenges of meaningfully assessing students' understanding of metabolic pathways and could inform how instructors think about teaching and assessing metabolism in undergraduate biochemistry and beyond. The results also suggest future avenues for biochemistry education research.

Making mechanistic sense: are we teaching students what they need to know?

Evaluating learning outcomes depends upon objective and actionable measures of what students know - that is, what can they do with what they have learned. In the context of a developmental biology course, a capstone of many molecular biology degree programs, I asked students to predict the behaviors of temporal and spatial signaling gradients. Their responses led me to consider an alternative to conventional assessments, namely a process in which students are asked to build and apply plausible explanatory mechanistic models ("PEMMs"). A salient point is not whether students' models are correct, but whether they "work" in a manner consistent with underlying scientific principles. Analyzing such models can reveal the extent to which students recognize and accurately apply relevant ideas. An emphasis on model building, analysis and revision, an authentic scientific practice, can be expected to have transformative effects on course and curricular design as well as on student engagement and learning outcomes.

Students' use of chemistry core ideas to explain the structure and stability of DNA

Students tend to think of their science courses as isolated and unrelated to each other, making it difficult for them to see connections across disciplines. In addition, many existing science assessments target rote memorization and algorithmic problem-solving skills. Here, we describe the development, implementation, and evaluation of an activity aimed to help students integrate knowledge across introductory chemistry and biology courses. The activity design and evaluation of students' responses were guided by the Framework for K-12 Science Education as the understanding of core ideas and crosscutting concepts and the development of scientific practices are essential for students at all levels. In this activity, students are asked to use their understanding of noncovalent interactions to explain (a) why the boiling point differs for two pure substances (chemistry phenomenon) and (b) why temperature and base pair composition affects the stability of DNA (biological phenomenon). The activity was implemented at two different institutions (N = 441) in both introductory chemistry and biology courses. Students' overall performance suggests that they can provide sophisticated responses that incorporate their understanding of noncovalent interactions and energy to explain the chemistry phenomenon, but have difficulties integrating the same knowledge to explain the biological phenomenon. Our findings reinforce the notion that students should be provided with opportunities in the classroom to purposefully practice and support the use and integration of knowledge from multiple disciplines. Students' evaluations of the activity indicated that they found it to be interesting and helpful for making connections across disciplines.

Step back, translate, extend: Addressing misconceptions relating to energy and free energy in cellular reactions via active-learning videos

In order to succeed in biochemistry, students must transfer and build upon their understanding of general chemistry and introductory biology concepts. One such critical area of knowledge is bioenergetics. Student misconceptions around energy and free energy must be addressed prior to learning more advanced topics, such as energy flow in metabolic reactions. In this article, we present a series of active-learning videos with embedded questions to address these crucial topics. This video module achieves the following goals: (1) review fundamental chemistry concepts, (2) introduce concepts of reaction coupling and ATP hydrolysis, and (3) foreshadow more advanced biochemical topics such as metabolism. These videos are offered free of charge as traditional videos through YouTube and as an active-learning video module through an online platform, Edpuzzle. Access to videos is provided at chemed.bu.edu.

Transfer: A Review for Biology and the Life Sciences

Transfer of knowledge from one context to another is one of the paramount goals of education. Educators want their students to transfer what they are learning from one topic to the next, between courses, and into the "real world." However, it is also notoriously difficult to get students to successfully transfer concepts. This issue is of particular concern in biology and the life sciences, for which transfer of concepts between disciplines is especially critical to understanding. Students not only struggle to transfer concepts like energy from chemistry to biology but also struggle to transfer concepts like chromosome structures in cell division within biology courses. This paper reviews the current research and understanding of transfer from cognitive psychology. We discuss how learner abilities, taught material, and lesson characteristics affect transfer and provide best practices for biology and life sciences education.

Probing the Relevance of Chemical Identity Thinking in Biochemical Contexts

The solving of problems in biochemistry often uses concepts from multiple disciplines such as chemistry and biology. Chemical identity (CI) is a foundational concept in the field of chemistry, and the knowledge, thinking, and practices associated with CI are used to answer the following questions: "What is this substance?" and "How is it different from other substances?" In this study, we examined the relevance of CI in biochemical contexts and first explored the ways in which practicing biochemists consider CI relevant in their work. These responses informed the development of creative exercises (CEs) given to second--semester biochemistry students. Analysis of the student responses to these CEs revealed that students incorporated precursors to CI thinking in more than half of their responses, which were categorized by seven previously identified themes of CI relevant to the presented biochemical contexts. The prevalence of these precursors in student responses to the CEs, coupled with the examples provided by practicing biochemists of contexts in which CI is relevant, indicate that CI thinking is relevant for both students training to be biochemists and practicing biochemists.

Connecting Structure-Property and Structure-Function Relationships across the Disciplines of Chemistry and Biology: Exploring Student Perceptions

While many university students take science courses in multiple disciplines, little is known about how they perceive common concepts from different disciplinary perspectives. Structure-property and structure-function relationships have long been considered important explanatory concepts in the disciplines of chemistry and biology, respectively. Fourteen university students concurrently enrolled in introductory chemistry and biology courses were interviewed to explore their perceptions regarding 1) the meaning of structure, properties, and function; 2) the presentation of these concepts in their courses; and 3) how these concepts might be related. Findings suggest that the concepts of structure and properties were interpreted similarly between chemistry and biology, but students more closely associated the discussion of structure-property relationships with their chemistry courses and structure-function with biology. Despite receiving little in the way of instructional support, nine students proposed a coherent conceptual relationship, indicating that structure determines properties, which determine function. Furthermore, students described ways in which they connected and benefited from their understanding. Though many students are prepared to make these connections, we would encourage instructors to engage in cross-disciplinary conversations to understand the shared goals and disciplinary distinctions regarding these important concepts in an effort to better support students unable to construct these connections for themselves.