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ABSTRACT Visual representations in molecular biology tend to follow a set of shared conventions for using certain shapes and symbols to convey information about the size and structure of nucleotides, genes, and chromosomes. Understanding how and why biologists use these conventions to represent DNA is a key part of visual literacy in molecular biology. Visual literacy, which is the ability to read and interpret visual representations, encompasses a set of skills that are necessary for biologists to effectively use models to communicate about molecular structures that cannot be directly observed. To gauge students’ visual literacy skills, we conducted semi-structured interviews with undergraduate students who had completed at least a year of biology courses. We asked students to draw and interpret figures of nucleotides, genes, and chromosomes, and we analyzed their drawings for adherence to conventions for representing scale and abstraction. We found that 77% of students made errors in representing scale, and 86% of students made errors in representing abstraction. We also observed that about half of the students in our sample used the conventional shapes and symbols to represent DNA in unconventional ways. These unconventional sketches may signal an incomplete understanding of the structure and function of DNA. Our findings indicate that students may need additional instructional support to interpret the conventions in common representations of DNA. We highlight opportunities for instructors to scaffold visual literacy skills into their teaching to help students better understand visual conventions for representing scale and abstraction in molecular biology. 

ABSTRACT Scientific publications, textbooks, and online educational resources rely on illustrated figures to communicate about molecular structures like genes and chromosomes. Published figures have the potential to shape how learners think about these molecular structures and their functions, so it is important that figures are clear, unambiguous, and free from misleading or incorrect information. Unfortunately, we found numerous examples of figures that contain representations of genes and chromosomes with errors that reflect common molecular biology misconceptions. We found published figures featuring Y-shaped Y chromosomes, replicated chromosomes incorrectly shown with different alleles on sister chromatids, single genes portrayed as wide bands on chromosomes, and genes consisting of only a small number of nucleotides. Drawing on our research on student thinking about visual representations in molecular biology, we critique these published figures that contain such misconceptions and provide recommendations for simple modifications to figures that may help scientists, science illustrators, and science educators more accurately communicate the structure and function of genes and chromosomes. 

Visual models are a necessary part of molecular biology education because submicroscopic compounds and processes cannot be directly observed. Accurately interpreting the biological information conveyed by the shapes and symbols in these visual models requires engaging visual literacy skills. For students to develop expertise in molecular biology visual literacy, they need to have structured experiences using and creating visual models, but there is little evidence to gauge how often undergraduate biology students are provided such opportunities. To investigate students’ visual literacy experiences, we surveyed 66 instructors who taught lower division undergraduate biology courses with a focus on molecular biology concepts. We collected self-reported data about the frequency with which the instructors teach with visual models and we analyzed course exams to determine how instructors incorporated visual models into their assessments. We found that most instructors reported teaching with models in their courses, yet only 16% of exam items in the sample contained a visual model. There was not a statistically significant relationship between instructors’ self-reported frequency of teaching with models and extent to which their exams contained models, signaling a potential mismatch between teaching and assessment practices. Although exam items containing models have the potential to elicit higher-order cognitive skills through model-based reasoning, we found that when instructors included visual models in their exams the majority of the items only targeted the lower-order cognitive skills of Bloom’s Taxonomy. Together, our findings highlight that despite the importance of visual models in molecular biology, students may not often have opportunities to demonstrate their understanding of these models on assessments. 

We explored undergraduate students' visual literacy by asking them to draw and interpret images of chromosomes and found that most students held incorrect or incomplete conceptions about chromosome structure and function. These findings stress the importance of teaching visual literacy skills in biology courses. 

A misconception among biology students is that breaking bonds in adenosine triphosphate (ATP) releases energy. This misconception may be related to imprecise representations of chemical bonding in common diagrams of ATP hydrolysis. We interviewed 33 undergraduate students and randomly assigned them to interpret a figure of ATP hydrolysis that either emphasized bond breaking in the reactants or the formation of new bonds in the products. Students who saw the figure emphasizing bond breaking were more likely to incorrectly classify ATP hydrolysis as endergonic, while students who saw the figure explicitly illustrating bond formation were more likely to use chemically-sound reasoning to describe the reaction. 

Using analogies is a standard practice for both teaching and communicating ideas in science. Here we upend the traditional lesson, where the instructor provides a fully constructed analogy and explains it, by having the students develop a complex analogy themselves. This high engagement, peer learning activity engages students in critical thinking and analogical reasoning to foster deeper understanding of molecular processes and their interconnection. In this lesson, groups of students are asked to relate given items to DNA and to decide which level it best represents (nucleotide, gene, chromosome, or genome). Next they are tasked with extending the analogy to include other actors in the central dogma of molecular biology (RNA, protein, polymerases, ribosomes, etc.), and then to extend it even further (introns/exons, mutations, evolution, etc.). Finally, each group presents their analogy to the class, and they evaluate each other. We provide multiple examples of items that can be used in the activity, but others can be identified with some creativity. This exercise is also an excellent tool for instructors to discover where their students have gaps and need help making connections to bridge their understanding of processes in molecular biology. 

Visual literacy, which is the ability to effectively identify, interpret, evaluate, use, and create images and visual media, is an important aspect of science literacy. As molecular processes are not directly observable, researchers and educators rely on visual representations (e.g., drawings) to communicate ideas in biology. 

Concepts of molecular biology and genetics are difficult for many biology undergraduate students to master yet are crucial for deep understanding of how life works. By asking students to draw their ideas, we attempted to uncover the mental models about genes and gene expression held by biology students ( n = 23) and experts ( n = 18) using semistructured interviews. A large divide was identified between novice and expert conceptions. While experts typically drew box-and-line representations and thought about genes as regions of DNA that were used to encode products, students typically drew whole chromosomes rather than focusing on gene structure and conflated gene expression with simple phenotypic outcomes. Experts universally described gene expression as a set of molecular processes involving transcription and translation, whereas students often associated gene expression with Punnett squares and phenotypic outcomes. Follow-up survey data containing a ranking question confirmed students’ alignment of their mental models with the images uncovered during interviews ( n = 156 undergraduate biology students) and indicated that Advanced students demonstrate a shift toward expert-like thinking. An analysis of 14 commonly used biology textbooks did not show any relationship between Punnett squares and discussions of gene expression, so it is doubtful students’ ideas originate directly from textbook reading assignments. Our findings add to the literature about mechanistic reasoning abilities of learners and provide new insights into how biology students think about genes and gene expression. 

From the perspective of a novice student, the molecular biosciences are inherently invisible. A challenge facing bioscience educators is to help students create detailed mental models of the biomolecules that make up a living cell and how they all work together to support life. With the advancement of rapid-prototyping, also known as 3D (three dimensional)-printing, physical models of biomolecules are entering undergraduate classrooms as tools to aid in constructing mental models of biological phenomena at the molecular-level.This relatively new pedagogical tool requires evidence-based practices for optimal use in aiding student conceptual and visual development.This chapter presents current evidence for the use of physical models as learning tools, while also introducing case studies on how physical models of biomolecules are designed and assessed in undergraduate molecular bioscience settings.