Commentary: Biochemistry re‐natured (2010)

My last commentary on “Biochemistry Denatured” dealt with my perception that college students today have spent too little of their childhood years playing outside in nature and as a consequence have not learned basic things about the world from personal experience [1]. This “nature-deficit disorder” [2] removes many opportunities for teachers to connect the abstractions of biochemistry to what was once assumed to be common knowledge. This phenomenon parallels the observation among engineers that students entering engineering had no experience playing with construction toys, such as Lincoln Logs, Tinker Toys, and Erector Sets. Consequently, they lacked basic skills that students in the past presumably had [3]. In response, courses described as “remedial play” have been designed for entering freshmen engineering majors. I do not advocate remedial nature play courses for entering biochemistry majors. Rather, I think that biochemistry can be “re-natured” in a mindful way that addresses these deficiencies. One simple way to help students relate biochemistry to everyday experience is to bring relevant objects into class, be it a leaf, flower, tissues, or something else. When talking about carbon isotope fractionation in a problem-based learning activity on photosynthesis, students in my intermediary metabolism class will have no idea what the Peedee belemnite is that is used for the reference standard for measuring δ13C. As it turns out, the same species of belemnite is the state fossil of Delaware, the home state of many of my students. I show these amber-colored, bullet-shaped fossil cephalopods to the students and they have lots of questions. Furthermore, they remember the discussion when asked about it later. With a little thought, relevant objects can be identified and displayed in class. Another approach involves using familiar objects to illustrate difficult ideas. John Jungck at Beloit College has developed a number of demonstrations that actively involve students. One has students become topoisomerases or polymerases struggling to disentangle giant super-coiled zippers [4]. Lecture demonstrations with familiar objects are yet another way to bring the visible natural world into the biochemistry classroom. Although biochemistry education lacks the rich tradition of lecture demonstrations identified with chemistry education [5-8], a single well-chosen demonstration in a semester can be sufficient to leave a lasting impression. One does not need a large repertoire. A demonstration I and a colleague developed many years ago, takes advantage of the riboflavin-binding protein in raw egg white [9]. The vitamin riboflavin is intensely fluorescent when exposed to UV light, however, its fluorescence is totally quenched when tightly bound to the protein. By titrating riboflavin into a UV-illuminated beaker of diluted egg white stirring in a darkened room, students can see the quenching of each successive aliquot of riboflavin until the binding protein is saturated at which time the solution suddenly glows yellow. As an aside, the brilliant scarlet fluorescence of the porphyrin pigments in the egg shell creates instant “Easter eggs” under the UV light. Another demonstration involves the changes in color, during the reversible oxygenation and deoxygenation of a solution of blood [10]. Dithionite, playing the role of the electron transport chain, reduces oxygen converting red oxyhemoglobin to purple deoxyhemoglobin. The process can be reversed by stirring in air. Such demonstrations can be transformed into investigative laboratory experiments, where students can purify and study the properties of hemoglobin starting with blood, rather than with dark red crystals from a bottle. Connections to the natural world abound and it shouldn't be too difficult to step back from our abstractions and make the connections for students. We would not have Taq polymerase or green fluorescent protein (GFP) without people who had curiosity about the natural world around them. Just about any major discovery or principle in biochemistry can be linked to a fascinating story often associated with a problem or observation from nature. Field trips may be an activity of the past at many schools, but why just talk about glycolysis if there is a brewery or winery nearby? Similarly, a visit to a laboratory that screens newborn infants for genetic diseases offers another possibility for relating biochemistry to the world of students. Even a walk in the woods can provide opportunities to see, smell, feel, and think about biochemistry in action. Powerpoint is only a vicarious substitute. Louis Agassiz simply stated what is now carved in stone on Lillie Laboratory at the Woods Hole Marine Biological Laboratory, “Study nature, not books” [11]. That is what Osamu Shimomura did there and shared the 2008 Nobel Prize in Chemistry for his discovery of GFP [12]. This is a great story that students might appreciate especially if they had experienced jellyfish growing up.