"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.

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.

Using PyMOL to Explore the Effects of pH on Noncovalent Interactions between Immunoglobulin G and Protein A: A Guided-Inquiry Biochemistry Activity.

Students' understandings of foundational concepts such as noncovalent interactions, pH and pKa are crucial for success in undergraduate biochemistry courses. We developed a guided-inquiry activity to aid students in making connections between noncovalent interactions and pH/pKa . Students explore these concepts by examining the primary and tertiary structures of immunoglobulin G (IgG) and Protein A. Students use PyMOL, an open source molecular visualization application, to (1) identify hydrogen bonds and salt bridges between and within the proteins at physiological pH and (2) apply their knowledge of pH/pKa to association rate constant data for these proteins at pH 4 and pH 11. The laboratory activity was implemented within a one semester biochemistry laboratory for students majoring in allied health disciplines, engineering, and biological sciences. Several extensions for more advanced students are discussed. Students' overall performance highlighted their ability to successfully complete tasks such as labeling and identifying noncovalent interactions and revealed difficulties with analyzing noncovalent interactions under varying pH/pKa conditions. Students' evaluations after completing the activity indicated they felt challenged but also recognized the potential of the activity to help them gain meaningful understanding of the connections between noncovalent interactions, pH, pKa , and protein structure. © 2017 by The International Union of Biochemistry and Molecular Biology, 45(6):528-536, 2017.