This online activity from A Science Odyssey web site developed by the Public Broadcasting System helps learners better understand the central dogma of biology by asking students to model the processes of DNA replication, transcription and translation using an interactive simulation. The activity prompts learners to correctly match base pairs to replicate and transcribe DNA and to correctly match codons to synthesize protein, giving instantaneous feedback along the way. The site also contains links to explanations of DNA replication, chromatin and protein synthesis as well as to historical vignettes of scientists and discoveries related to the central dogma.
A student will understand :
• Understand the structure of DNA and the process of DNA replication
• Understand the process of transcription
• Describe the process of protein synthesis
• Understand where these processes take place within the cell
Target Student Population:
High school or undergraduate.
Prerequisite Knowledge or Skills:
Genetics or cell biology.
Type of Material:
Could be used as an in class activity or study aid
Evaluation and Observation
• Explanations contain good analogies to help novices better grasp the concepts
• Explanations within activity describe the differences between the simulation and what really occurs in vivo
• Contains links to relevant sections within the PBS site for further learning
• Contains a glossary of term
• As a way to better demonstrate how the 3 processes fit together to form the central dogma of biology, it would be helpful if the site included a model showing an overview of how the 3 steps of DNA replication, transcription and translation fit together.
• The design of the activity may lead to some confusion, as students can add the bases in a random order to the template. There is also no polarity (5' to 3') indicated. So the students may come away with the impression that the enzyme adds bases anywhere along the template instead of building off the 3' end.
Potential Effectiveness as a Teaching Tool
• Repetitive nature of the activity provides good drill and practice for students to master the basics of DNA structure and replication
• The small image of the cell showing the location of each process helps learners to think about the processes in the context of a cell
• An accompanying site within the PBS website called Teachers’ Domain Life Science contains teaching resources such as background information, discussion questions and grade 9-12 lesson plans that incorporate the web activity
• Students get to use a template to produce DNA or RNA, and pair complementary bases. Students also get to pair anticodons with codons to produce a protein. This animation is much more accurate than those for replication and transcription.
• The text on the website emphasizes DNA replication and protein synthesis but not transcription. It would be more complete if the site described the central dogma of biology as consisting of all 3 processes: DNA replication, transcription and protein synthesis.
• The same concerns raised under Content Quality apply here, students may become confused by how replication and transcription actually occur.
Ease of Use for Both Students and Faculty
• Easy to navigate
• Well designed
• Simple but effective graphics
• Logical flow
• Fast speed
• Instructions are not immediately clear. It would be better if the instructions included in the “help” link were displayed initially.