Using BioInteractive Resources to Develop a Storyline to Anchor a College Laboratory
Using a Storyline
I teach the introductory Foundations of Cell Biology and Genetics course for biology majors at a small liberal arts institution in Indiana. Our town is very famous for an ice cream parlor called Ivanhoe’s. One of the first questions I ask my students is how many of them don’t eat ice cream. This leads to the question of why some people can digest milk and others can’t: an anchoring phenomenon that engages students in their learning.
I use the anchoring phenomenon of lactase persistence (the ability to digest lactose sugar in milk when an adult) to engage my students in class and laboratory. Yes, even in the laboratory! This approach allows me to connect class concepts with our laboratory sections. An anchoring phenomenon that links lab and class materials can be a valuable tool, as it creates a storyline — a coherent lesson sequence — that brings relevance and reasoning (Claim-Evidence-Reasoning) to the content knowledge of the course. Students ask questions about the phenomenon and how it relates to their own lives, creating wonder and natural curiosity, as well as deepening interest and engagement.
My storyline around lactase persistence, which is a relatively recent adaptation in humans, incorporates and connects the major concepts of cell biology, molecular biology, bioenergetics, genetics, evolution, and the nature of science. For example, the enzyme regulation involved in lactase persistence links molecular and cellular concepts. It also highlights cellular principles across scales from prokaryotes to populations. Most importantly for learning, it enhances the relevance of the content through personal connections. And it not only deepens students’ understanding of these concepts but also highlights the processes of science.
BioInteractive Planning Tools
BioInteractive provides tools and examples that help in planning a storyline or unit using an anchoring phenomenon; you can also select a lesson sequence that they have developed from their Resource Playlists collection or the Storyline Viewer tool.
I developed the lactose intolerance storyline for my introductory class and labs several years ago and have used many of BioInteractive’s resources. Almost all are found in this BioInteractive playlist: “Teaching Genetics and Molecular Biology Using Lactose Intolerance.”
If you’d like a more detailed storyline, Storyline Viewer has two example storylines around lactase persistence: one focused on genetics and another on evolution. Using Storyline Viewer helped me develop my lab storyline. Other helpful resources I used to create this storyline are the “Lactase Persistence: Evidence for Selection” activity and the Got Lactase? The Co-evolution of Genes and Culture short film.
A Closer Look at the Storyline in Lab
The laboratory that I developed incorporates all of our previous stand-alone labs and links multiple areas of biology under the subject of lactase persistence. This storyline has a cohesive structure revolving around the need to obtain energy from sugars (glucose and galactose from lactose) to survive. To kick things off, we use the Bee Gees song “Stayin’ Alive” as our theme. To stay alive requires obtaining energy from sugars for the conversion of ADP to ATP.
The storyline contains three linked units, which are detailed below. As shown, we use a variety of BioInteractive resources to connect individual lab techniques with the science in them. In each unit, we require students to present posters that highlight certain aspects of the labs. These posters include a literature review, a daily lab log, formation of hypotheses, development of lab protocols to test hypotheses, data collection, analysis and display, and conclusions and recommendations.
Unit 1 (4 labs)
In Unit 1, we use the lactase persistence phenomenon to introduce classic cell structures and processes, including the need for energy. This unit highlights cell respiration, glucose and enzymes, enzymatic control, and biochemical pathways. Our storyline here examines how prokaryotes and eukaryotes acquire energy from sugars and how they use specific enzymes to break down these sugars in cellular respiration. The short BioInteractive animations on cellular respiration provide excellent resources for these labs: Glycolysis, Pyruvate Dehydrogenase, Citric Acid Cycle, Electron Transport Chain, ATP Synthesis, and ATP in Use.
The four labs in this unit explore the ability of yeast to digest and use common sugars, including lactose. Students examine enzyme structure and kinetics, as well as the development of hypotheses (general and explanatory) leading to testable predictions. Students also learn to develop protocols to test their predictions. We then introduce how prokaryotes regulate enzymes through discussion of the lac operon. BioInteractive’s LUX Operon animation helps deepen student understanding. Students learn that regions outside of the genes provide mechanisms to turn genes on and off.
The students present their findings for Unit 1 in a poster session, highlighting cell structures, processes, hypotheses, predictions, and protocols. These posters focus on how different types of yeast vary in their abilities to obtain energy. Students recognize that yeast need specific enzymes to break down certain sugars for energy.
The key part of the third lab transitions from respiration in prokaryotes to cell respiration in eukaryotes. Lactase persistence as an anchoring phenomenon helps to personalize the information for students. The lesson-specific phenomenon uses the animation Lactose Digestion in Infants. The animation shows how the lactase enzyme breaks down the sugar lactose in the small intestine in infants. This prompts students to ask two questions: “Why do most mammals, including humans, stop making lactase after they are weaned from milk? And how is this ability regulated?”
Unit 2 (2–3 labs)
This unit addresses lactose digestion in mammals, gene expression related to lactase persistence, and the prevalence of lactase persistence in the human population. Students’ own ability or inability to digest lactose becomes the focus.
By this point in the sequence, students who are lactose intolerant are beginning to find out how common it is, and how that can be related to their culture or ethnicity. Students watch a clip from the short film Got Lactase? The Co-evolution of Genes and Culture, and then examine profiles of individuals from around the world based on their cultural practice of dairying or access to dairy products. Students indicate these dietary patterns on a map of the world and answer the following prompt: “Does their diet allow for milk or milk products? Propose hypotheses of why or why not.”
They then use data from a scientific paper (Gerbault et al. 2011) to map the frequency of lactase persistence across different continents. Although most adult mammals (including approximately 70% of adult humans) are unable to digest lactose, the ability to digest lactose as an adult exists in human population hot spots scattered around the world.
Students arrive at these questions: “What causes lactase persistence? And why is lactase non-persistence/lactose intolerance more common in some populations than in others?” Lastly, and perhaps most importantly, they ask: “Why am I lactose tolerant/intolerant?”
Students explore their own ability to digest lactose by doing a blood glucose analysis, as seen in the Got Lactase? film. They drink milk, do a blood glucose analysis, and ask questions, e.g., “What causes glucose levels to increase in a person’s bloodstream after they drink milk? And why do only some people experience this effect?” (Students who are lactose intolerant or do not want to drink milk do not do this exercise and are provided with data.)
This experience allows students to explore the specific phenomenon of blood glucose levels increasing in some people and not others because of the action of the lactase enzyme. It also brings us to the question of how people usually are able to digest milk when they’re infants but not when they’re adults. What turns this switch on and off?
As in Unit 1, students present their findings for Unit 2 in a poster session. These posters focus on developing hypotheses and writing predictions, which students learn more about in Unit 3.
Unit 3 (4 labs)
In the first lab, we begin by exploring the structure of DNA and genes, and introduce gene regulation using BioInteractive’s Regulation of the Lactase Gene Click & Learn. We also begin to develop hypotheses and predictions for students’ results from the blood glucose lab. The “Student Worksheet” for the Central Dogma and Genetic Medicine Click & Learn provides a good visual and reminds students about transcription, translation, and enzymes studied in the course.
The remaining labs introduce the students to the molecular techniques to determine if they have the lactase persistence mutation. Students perform DNA extractions, PCR, restriction digests, gel electrophoresis, and gene mapping of the lactase regulatory mechanism. The course ends with a poster presentation of their study and answers to their predictions.
We often provide time in class for students to reflect on how the cellular mechanisms of lactase persistence relate to a population’s adaptations and also to their own personal ability to digest lactose. Reflections are first discussed in lab groups, then brought by a representative to the whole class for consideration.
Over the years of developing this approach, I have received extensive reflective comments concerning these laboratories and their anchoring phenomenon. For example, “I understand better what heterozygous means concerning protein production.” “Using my own DNA makes cell biology more understandable.”
My favorite discussion came at the end of the course and extended into the sophomore genetics course and the human anatomy and physiology (A&P) course. One student talked about her lactose intolerance. She noted her disappointment in being unable to eat the ice cream from Ivanhoe’s. Her prediction for the lab was that she would have a regulatory sequence that turns off lactase production in adults. She expected that her RFLP bands would indicate no recent adaptive mutation that allows lactase gene expression (Ex. Lane E in the figure below, which shows results from an anonymized sample).
However, when her results came in, the banding indicated that she did have the mutation that enables her to produce lactase. We discussed for over a year how this could happen when we would run into each other before her sophomore A&P class. She tried taking lactase products to digest milk, but it did not relieve her of symptoms. After learning more about allergies in class, she then proposed that she test for an allergy to a protein in milk, not lactose. She is now happily eating ice cream made with milk that does not have that protein. This is one of my favorite examples because it so clearly shows how the student anchored her understanding of energy acquisition and gene regulation on a personal level.
Takeaways
For me, creating this storyline allowed the lab to become an integral and connected part of student learning. Each student’s results from the study increased their engagement in the course materials, as well as in the field of biology, and provided an opportunity to reflect on how they learn. It was a win-win!
References
Chao, Christina K., and Eric Sibley. “PCR-RFLP Genotyping Assay for a Lactase Persistence Polymorphism Upstream of the Lactase-Phlorizin Hydrolase Gene.” Genetic Testing 8, 2 (2004): 190–193. https://doi.org/10.1089/gte.2004.8.190.
Gerbault, Pascale, Anke Liebert, Yuval Itan, Adam Powell, Mathias Currat, Joachim Burger, Dallas M. Swallow, and Mark G. Thomas. “Evolution of lactase persistence: an example of human niche construction.” Philosophical Transactions of the Royal Society B: Biological Sciences 366, 1566 (2011): 863–877. https://doi.org/10.1098/rstb.2010.0268.
Schultheis, Patrick J., and Bethany V. Bowling. “Analysis of a SNP Linked to Lactase Persistence: An Exercise for Teaching Molecular Biology Techniques to Undergraduates.” Biochemistry and Molecular Biology Education 39, 2 (2011): 133–140. https://doi.org/10.1002/bmb.20456.
Troelsen, Jesper T., Jørgen Olsen, Jette Møller, and Hans Sjöström. “An Upstream Polymorphism Associated With Lactase Persistence Has Increased Enhancer Activity.” Gastroenterology 125, 6 (2003): 1686–1694. https://doi.org/10.1053/j.gastro.2003.09.031.