In this activity students construct an analogy between the central dogma and a robot “running a program”. Students are first asked to place the central dogma (DNA-RNA-Protein) in the correct order and then asked what robot parts or actions are similar to the central dogma. This lesson is a great way to establish a concrete understanding of the central dogma, the purpose of DNA in controlling cell behavior, and for identifying misconceptions in student understanding of DNA or the central dogma.
What is the purpose of DNA?
What processes convert DNA into cell behavior or output? (What is the central dogma?)
How does programming a robot model DNA’s control over cell behavior?
central processing unit (CPU)
- Cell-to-Robot Word Puzzle
- Vocabulary word cards – half index cards with vocab words written on each
- Vocabulary words: All the robot parts (all Lego bricks), the wires that connect the motors and sensors to the CPU (brick), the computer used to program the robot, DNA, cellular engineering, genetic engineering, nucleus, the program (programming), building the robot, transcription, central processing unit (CPU, the “brick”), RNA, running a program, wires, editing a program, taking the robot apart, battery, the robot’s sensors and motors, charging the battery, translation, protein
Groups of 3-4 students
5 mins – Introduction
10 mins – Activity
10 mins – Wrap-up/Closure
Prerequisites for students
Students must first have experience programming or programming a robot. Background knowledge of the central dogma, including the process of transcription and translation, is also recommended before this activity. This activity was designed to follow a lesson using LEGO mindstorm robots, so some cards that specifically reference LEGOs may need to be replaced or rewritten to avoid confusion.
Learning goals/objectives for students
Students should learn the correct order of the central dogma and be able to describe where transcription occurs within the cell. Students should then be able to construct an analogy between DNA and programming. Students should understand that DNA can be thought of as the cell’s “programming,” which can be manipulated through cellular or genetic engineering. Also, as running a program within robot results in actions by the robot, students should learn that transcription and translation results in a protein product and/or cellular action.
Content background for instructor
DNA contains the all instructions within the cell that determine its structure and behavior. Every part of the cell and every cellular action is controlled in some way by DNA. For example, certain protists have light sensors (or eyespots) that are constructed from proteins (i.e. photoreceptors and other structural proteins) that are built within a cell using a DNA blueprint. Moreover, certain enzymes, like β-galactosidase (which cleaves the disaccharide lactose into glucose and galactose), is controlled by turning the LacZ gene on and off.
DNA within a cell holds a similar function to programming within a robot. Both use some form of logic (i.e. if/then statements in programs and protein promoters/repressors in DNA) to control behavior (Note: new cell parts can be formed from DNA blueprints but robot programming may not be too simple to construct new robot parts.). A robot generally has a central processing unit (CPU) that converts the instructions of a program into a series of outputs into its servo motors, wheels, or other components. This is similar to how cells store DNA inside its nucleus, and convert DNA messages to RNA and then protein to accomplish a cellular behavior.
As robot programming can be modified, DNA within a cell can be modified as well. The STEM discipline focuses on editing DNA is genetic engineering. Cellular engineering is focused on understanding the structure and behavior of cells in order to manipulate cell behavior for a particular function. One way to manipulate cell behavior or structure would be to edit the cell’s genes. Therefore, while cellular engineering and genetic engineering are not equivalent disciplines, cellular engineers will often use genetic engineering to accomplish a cellular engineering goal.
You will need one Cell-to-Robot Word Puzzle mat and one set of 21 vocabulary cards per group. The mat is 11’x17’ (a double sheet). Squares on the mat have been sized to fit ½ of an index card. Words can be written (or printed on labels) on each ½ index card. The 21 vocabulary words are:
All the robot parts (all Lego bricks), the wires that connect the motors and sensors to the CPU (brick), the computer used to program the robot, DNA, cellular engineering, genetic engineering, nucleus, the program (programming), building the robot, transcription, central processing unit (CPU, the “brick”), RNA, running a program, wires, editing a program, taking the robot apart, battery, the robot’s sensors and motors, charging the battery, translation, protein
Pass out the Cell-to-Robot Word Puzzle Mat and a set of vocabulary cards for each group.
This is best done immediately after students have had a chance to program a robot on their own. Explain that the mat has questions within each square. Their group must discuss which card has the vocabulary word that best answers each question. Explain that they should start with the grey squares first (biology specific questions) and then to the white squares. **Some of the white squares can have more than one correct answer!
Allow groups to begin placing cards on the mat. Alternatively you can do this activity in two sessions (first grey squares, then white squares).
Checking for student understanding
Walk around the room to answer any questions. Encourage groups to engage in discussion and use evidence to determine which cards should be placed where.
Complete a “class mat” to allow groups to share out answers. Use a projector to project a single word puzzle mat to the entire class so they can see where each card is placed. Ask students where they placed each vocabulary word on their mat as you assemble the “class mat”. It’s best to start by placing DNA, RNA, protein, and then ask where transcription and translation should be placed (as these two processes are often confused).
Grey square answers (form left to right in the central row): DNA, transcription, RNA, translation, protein. (bottom grey square): nucleus
Then ask the class for their thoughts on the white squares. Remind the class that white squares can have more than one answer, so when a student offers their groups answer, they should explain their reasoning for selecting that card for that space.
White square answers (starting with top left corner):
- Which biological STEM discipline is similar to studying and editing the robot part decribed below? Both “cellular engineering” and “genetic engineering” could be placed here. The STEM discipline that focuses on editing DNA is genetic engineering. Cellular engineering is focused on understanding the structure and behavior of cells in order to manipulate cell behavior for a particular function. One way to manipulate cell behavior or structure would be to edit the cell’s genes. Therefore, while cellular engineering and genetic engineering are not equivalent disciplines, cellular engineers will often use genetic engineering to accomplish a cellular engineering goal.
- What robot part is similar to the molecule below? “the program/programming”. This is a central concept to the analogy between a cell and a robot. DNA is like the cell’s programming.
- What is something the robot does that is similar to the entire process described by the five boxes below? “running the program”. This is a great time to remind students that the five boxes constitute the central dogma.
- What robot part is similar to the part of the cell described to the left?” both “the computer used to program the robot” and “the CPU” could be placed here. As students may have programmed with their computer, they may feel that this best represents where the program “resides” and where it was created. However, once the robot downloads the program into its CPU, it can run the program several times without needing to reconnect with the computer. Both have shortcomings as a direct model to a cell. Encourage discussion to deepen student understanding.
A natural extension would be a discussion on mutations that result in genetic diseases. What happens when the robot’s program is corrupted? What if one line or one part of the program is erased or rewritten? Will the program still work? How is this similar to the effect of changing or deleting a nucleotide in a gene (within DNA)?
Inheritance and Variation of Traits
ETS2 Links Among Engineering, Technology, Science, and Society
HS-LS1-1 From Molecules to Organisms: Structures and Processes
(DNA determines the structure of proteins, which preform the functions of life, just as programs determine the actions of a robot.)
HS-LS3-1 Heredity: Inheritance and Variation of Traits
(DNA is the coding instructions for characteristic traits (and behaviors), just as programs determine the actions and behaviors of a robot.)
Disciplinary Core Ideas
HS LS1.A Structure and Function
HS LS3.A Inheritance of Traits
ETS2.A Interdependence of Science, Engineering, and Technology
(Connections between the structure of cells and robots demonstrates a connection between scientific observation and engineering design. Also cellular engineering and genetic engineering are linked as cellular engineering often uses the tools from genetic engineering to solve cellular engineering problems.)
Science and Engineering Practices
Practice 1. Asking Questions and Defining Problems
Practice 2. Developing and Using Models
Practice 6. Constructing Explanations and Designing Solutions
Cause and effect
Systems and System Models
Structure and Function