It also connects the content of molecular biology with that of genetics by helping students understand mutations, the effects of mutations on protein sequence, and the relationship between genetic
mutations, protein sequence, and disease (genotype → phenotype).
As a result, this activity may help address some of the issues surrounding students’ difficulties reconciling proteins and phenotypes
as discussed in the literature (Marbach-Ad, 2001; Speth et al.,
2014; Reinagel & Speth, 2016). By allowing students to actively
work through these concepts using simple coded shapes, they
build their own understanding and actively refute many of their
own inherent misunderstandings. After working through these
tasks, it is an easy conceptual jump for the students to think of
the single-letter representations of nucleotides (A, C, G, and T) as
a code similar to the shapes used in this activity. The letters represent actual chemical structures, which are as meaningful a code to
the cellular machinery as the shapes are to us in deciphering the
code. This connection is made within the accompanying discussion
slides available for download. Students also gain an introductory
understanding of the role of promoter regions and understand that
genes are embedded within longer sequences that make up our
As with all models, this model has some limitations. Transcrip-
tion (DNA → RNA) has been largely ignored in order to focus more
directly on translation and key aspects of turning the genetic code
into protein. Teachers should be aware that this results in having
an RNA “genome,” since the code (representing the genome) is
directly decoded into a chain (representing protein) using a version
of the genetic code, thus using uracil instead of thymine. In our
experience, this has not been an issue as students tend to under-
stand transcription fairly well and easily accept the minor altera-
tions that were made for simplicity’s sake. Having extensively
used the genetic code during this activity, students tend to have
no problem making the transition from uracil to thymine, or learn-
ing the intermediate step of transcription that was ignored in this
activity. When used as an introduction, this activity sequence pro-
vides a central lattice on which student understanding of concepts
central to molecular biology and molecular genetics can be built.
Duncan, R.G. & Reiser, B.J. (2007). Reasoning across ontologically distinct
levels: students’ understandings of molecular genetics. Journal of
Research in Science Teaching, 44, 938–959.
Marbach-Ad, G. (2001). Attempting to break the code in student
comprehension of genetic concepts. Journal of Biological Education, 35,
Marbach-Ad, G., Rotbain, Y. & Stavy, R. (2008). Using computer animation
and illustration activities to improve high school students’
achievement in molecular genetics. Journal of Research in Science
Teaching, 45, 273–292.
Marshall, P.A. (2017). A hands-on activity to demonstrate the central dogma
of molecular biology via a simulated VDJ recombination activity.
Journal of Microbiology & Biology Education, 18(2).
NGSS Lead States (2013). Next Generation Science Standards: For States, By
States (HS-LS3-1 and HS-LS3-2). Washington, DC: National Academies
Reinagel, A. & Bray Speth, E. (2016). Beyond the central dogma: model-based learning of how genes determine phenotypes. CBE–Life Sciences
Education, 15, ar4.
Rotbain, Y., Marbach-Ad, G. & Stavy, R. (2008). Using a computer animation
to teach high school molecular biology. Journal of Science Education
and Technology, 17, 49–58.
Speth, E.B., Shaw, N., Momsen, J., Reinagel, A., Le, P., Taqieddin, R. & Long,
T. (2014). Introductory biology students’ conceptual models and
explanations of the origin of variation. CBE–Life Sciences Education, 13,
Takemura, M. & Kurabayashi, M. (2014). Using analogy role‐play activity in
an undergraduate biology classroom to show central dogma revision.
Biochemistry and Molecular Biology Education, 42, 351–356.
MICHAEL I. DORRELL ( firstname.lastname@example.org) is a Professor of Biology at
Point Loma Nazarene University. He is also a senior staff scientist
consultant at the Lowy Medical Research Institute and an adjunct
professor at the Scripps Research Institute. JENNIFER E. LINEBACK
( email@example.com) is an Associate Professor at Point Loma
Nazarene University with a joint appointment in the Biology Department
and the School of Education. She is also the Department Chair of Cross-Disciplinary Studies within the School of Education.
Figure 5. Conceptual understanding of the effects of
insertions and deletions on the reading frame.