DNA to Protein Structure and Function: The Mutation Challenge
Objective
Students will explore how the sequence of DNA determines the sequence of amino acids in a protein, and how the resulting 3D structure of the protein dictates its function within specialized cells. Students will investigate the effects of different types of mutations on protein function.
NGSS Standards
- Performance Expectation: HS-LS1-1. Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.
- Science and Engineering Practices (SEP): Constructing Explanations and Designing Solutions.
- Crosscutting Concepts (CCC): Structure and Function.
Introduction
Proteins are the workhorses of the cell, carrying out almost every essential function necessary for life. But how does a cell know how to build the right proteins? The instructions are coded in your DNA! In this simulation, you will observe the process of transcription (DNA to mRNA) and translation (mRNA to protein). You will act as a geneticist, exploring what happens when the DNA code is altered (mutated) and how these changes impact the protein’s ability to do its job in specific cells like muscle cells, red blood cells, and immune cells.
Instructions
- Open the DNA to Protein Structure and Function Simulation.
- Explore the Interface: Notice the DNA sequence at the top. The coding strand is editable. Below it, observe the resulting mRNA sequence and the chain of amino acids (protein).
- Mutate the DNA: Click on any base in the top row of the DNA sequence to change it. Observe what happens to the mRNA and the amino acids.
- Observe Structure and Function: On the right side of the screen, watch how the amino acid sequence folds into a specific 3D shape. Select different “Cell Types” (Muscle, Red Blood Cell, Immune) to see if the current protein shape functions correctly in that environment.
- Use the Presets: Below the Evidence Log, you will find “Goals & Challenges” buttons. Use these to reset the simulation and explore specific scenarios.
Data Collection
Use the “Record Current Data” button to save your observations to the Evidence Log. You must collect data for at least 5 different sequences, including:
- The original (Normal) sequence for the Muscle cell.
- The mutated sequence that completes the Sickle Cell Challenge.
- The mutated sequence that completes the Premature STOP Challenge.
- The mutated sequence that completes the Silent Mutation Challenge.
- At least one custom mutation that you create yourself.
| DNA (Coding) | Amino Acids | Protein Shape | Cell Type | Function Outcome |
|---|---|---|---|---|
| ATGGTGTACCTG | Met-Val-Tyr-Leu | Fibrous Rod (Myosin-like) | Muscle Cell | Success: Rod structure enables muscle contraction. |
| … | … | … | … | … |
(Note: Use the simulation’s built-in Evidence Log table to gather this data, then transfer it to your lab notebook or worksheet.)
Analysis Questions
- The Process of Protein Synthesis: Briefly describe the flow of information from DNA to a functional protein, naming the two main processes involved. How does changing a single DNA base potentially change the entire outcome?
- Sickle Cell Challenge: What specific change occurred in the amino acid sequence when you completed the Sickle Cell Challenge? How did this affect the 3D shape of the protein, and why did this cause the red blood cell to fail its function?
- Premature STOP Challenge: What happens to the protein when a STOP codon is introduced early in the sequence? Why is a truncated protein usually non-functional?
- Silent Mutation Challenge: Explain how it is possible to change the DNA sequence without changing the final protein structure or function. What feature of the genetic code allows for this?
- Structure and Function Relationship: Based on your observations of the Muscle, Red Blood Cell, and Immune cell environments, explain why a protein’s 3D shape is critical to its specific job. Provide one specific example from the simulation.
Final Conclusion
Construct an Explanation (HS-LS1-1): Write a well-developed paragraph explaining how the structure of DNA ultimately determines the structure and function of specialized cells. Use specific evidence from your Evidence Log and the simulation to support your claim. Be sure to connect the sequence of nucleotides to the final 3D shape of the protein and its cellular environment.