DNA and protein modeling
Open your materials, follow the steps, then turn in your work.
Model transcription and translation following an SOP and introduce a mutation to observe its effect.
1. Open your materials
Use the materials named in the first step below. Open lesson resources.
2. Start the work
Read the modeling SOP and set up a DNA template strand.
Show all 5 required steps
- Read the modeling SOP and set up a DNA template strand.
- Transcribe the template into mRNA, recording each base pair.
- Translate the mRNA into an amino acid sequence using a codon chart.
- Introduce a point mutation and re-translate to compare the protein.
- Record one limitation of the model and one source of error.
Lost your place? Lost your place? Check the SOP: (1) template set up, (2) mRNA transcribed, (3) amino acids read from the codon chart, (4) one base mutated and re-translated. Restart at your last completed step, then log one limitation and one source of error.
Check your work before submitting
- I can model transcription and translation accurately.
- I can show how a mutation alters a protein.
Before lab work: read the safety rules
- This is a paper/physical modeling activity; standard classroom safety applies.
- If using plastic model kit pieces, do not put small pieces in your mouth and store all pieces in their labeled bag at the end of class.
- Handle scissors with care; pass them closed, handle-first.
- Return all model materials to the designated storage location at the end of class so they are available for subsequent periods.
3. Turn in your work
DueCheck Schoology- Hand in
- Lab notebook entry: original DNA template strand, mRNA transcription, original amino acid sequence (with codon chart citations), mutated sequence after the point mutation, mutation type classification with justification, and one model limitation.
How to submit and name your file
Photograph your notebook entry and upload to the tracker before leaving class.
In Schoology, open your course and the assignment for this lesson. Attach your file, select Submit, and check that it appears in the submission.
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How this lesson connects
Keep using what you learned last class: A trend describes direction, speed, and position relative to the normal range, so reading the trend rather than any single value tells you whether a chronic condition is improving or worsening, because one reading can be distorted by a meal, stress, or lab error. Today: Modeling transcription and translation by hand makes each base pairing visible, so you can pinpoint exactly where one changed base rewrites the protein.
Check you have the right sheet: the top of it prints today's portal day, DNA and protein modeling. The PLTW activity itself is in myPLTW and is not posted here.
Optional: listen or watch a unit review▸
Need help? Warm-up, timing, and directions▸
💡 Big idea: Modeling and by hand makes each base pairing visible, so you can pinpoint exactly where one changed base rewrites the .
- 0:00Quick review of Tuesday's pre-lab: confirm template sequences; check codon chart is accessible
- 0:10: write the mRNA sequence complementary to the template; verify against a partner before proceeding
- 0:22: use the codon chart to identify each amino acid; write the full original amino acid sequence
- 0:38: change one specified base in the DNA template; re-transcribe and re-translate; record the new amino acid sequence
- 0:56Classify the type (silent, , or ) and record in the notebook with justification
- 1:05Record one model limitation and one source of error; preview Thursday analysis
- • Today you are going to physically model the central dogma. You will use your pre-lab sequence, transcribe it to mRNA base by base, translate it to an amino acid sequence codon by codon, and then change one base and see what happens.
- • The codon chart is your decoder ring. Every three bases in the mRNA corresponds to exactly one amino acid, with two exceptions: start (AUG) and stop (UAA/UAG/UGA). Know those before you start.
- • The is the heart of today's lab. You are going to discover for yourself whether a single base change is catastrophic, minor, or completely silent. The type of mutation determines the answer.
- • Read the SOP before you begin. Record every base pair as you write it. Do not skip steps and fill them in later, because errors compound quickly in a sequence model.
- • In , the template strand is read 3' to 5' and the mRNA is synthesized 5' to 3'; each DNA with its RNA complement (A with U, T with A, G with C, C with G).
- • In , each mRNA codon (triplet of bases) specifies one amino acid using the codon chart; a stop codon (UAA, UAG, UGA) terminates the chain.
- • A silent changes the DNA but produces the same amino acid (due to codon degeneracy); a mutation changes one amino acid; a mutation introduces a premature stop codon.
PLTW connection and today's work
In myPLTW, open Lesson 2.2 Decoding a Diagnosis and go to Activity 2.2.2 A Protein Problem. Record your original and mutated amino acid sequences there.
Today's stopping point: You prepared your mutation plan Tuesday. By the end of today both the original and mutated sequences should be complete in your notebook.
PLTW activity titles identify the course connection. If your account will not open, use the posted materials for today and tell Mr. Mendoza. Do not mark an online activity complete unless you completed it.
Use the turn-in directions at the top of this page. Do not create a second submission unless your teacher asks for one.
Show another explanation or a smaller first step
Need help? Choose a starting point
Finish the assigned lab safely before starting extra practice.
Lesson resources: reading, slides, and vocabulary▸
The deck carries the prior idea forward, lets you inspect an analogy, maps the rule to biology, and ends with the same evidence decision and exit ticket used on this page.
Generated from this lesson's canonical data with a red-team citation check.
A trend describes direction, speed, and position relative to the , so reading the trend rather than any single value tells you whether a chronic condition is improving or worsening, because one reading can be distorted by a meal, stress, or lab error.
Modeling and by hand makes each base pairing visible, so you can pinpoint exactly where one changed base rewrites the .
A library keeps a master plan protected while working copies guide production at different stations.
- Why protect the master copy?
- What information moves?
- Where can an error change the final product?
Stored information can be copied, read, and converted into a functional product.
Genes are regulated biological sequences, not conscious instructions, and one gene rarely determines a whole trait alone.
- • Master plan maps to DNA.
- • Working copy maps to RNA.
- • Production output maps to or a regulated cell function.
Driving question: When you transcribe and translate a real DNA strand by the SOP and then change one base, what happens to the amino acid sequence, and why?
What you already know: A trend describes direction, speed, and position relative to the , so reading the trend rather than any single value tells you whether a chronic condition is improving or worsening, because one reading can be distorted by a meal, stress, or lab error.
New idea: Modeling and by hand makes each base pairing visible, so you can pinpoint exactly where one changed base rewrites the .
Visual or model: F1. F1. A lesson illustration or teaching diagram for DNA and protein modeling. Use it with E1-E3; it is a model or context image, not experimental or patient data. What to notice: Trace the labeled observation or evidence sequence before choosing an explanation.
- Observe or measure the relevant feature in today's lesson.
- Organize the observation with a stable evidence ID.
- Apply this rule: Stored information can be copied, read, and converted into a functional product.
- Choose the option the evidence supports and state the limit of the conclusion.
Real biomedical example: When you transcribe and translate a real DNA strand by the SOP and then change one base, what happens to the amino acid sequence, and why?
What the evidence supports: E1-E3 and F1 support the daily take-home when the response meets the stated success criteria.
What it cannot prove: The package does not support claims beyond this lesson's or any real patient diagnosis.
- • DNA: The molecule that stores genetic instructions in a twisted double helix, with paired bases that spell out the code for building an organism.
- • : A tightly coiled package of DNA wrapped around proteins that carries genes; humans normally have 46 of them, arranged in 23 pairs.
- • gene: A stretch of DNA that codes for a product (usually a ) and carries an instruction for the cell.
- • : One of the alternative versions of a gene found at the same spot on a , like the A, B, and O versions of the blood-group gene.
- • : A folded chain of amino acids that a gene's instructions are used to build, serving as the cell's machines and structural building blocks.
- • : The first step of making a : copying a DNA gene into messenger RNA.
- • : The second step of making a : the ribosome reads the mRNA and builds a chain of amino acids.
- • : A change in the ; some change a enough to cause disease, many do not.
Use it now: Choose one decision option. Cite E1 and E3, then explain how the rule connects the evidence to your choice.
Go further, optional: The source links below are optional enrichment. Every fact required for today's local evidence decision appears in this lesson package.
Genetic evidence can support an inheritance, , sequence, or expression explanation, but penetrance, regulation, environment, family structure, and test uncertainty can limit the conclusion.
Limit: A classroom , , pedigree, or molecular model does not establish a real person's diagnosis, prognosis, identity, or reproductive outcome.
Stored information can be copied, read, and converted into a functional product.
Limit: Genes are regulated biological sequences, not conscious instructions, and one gene rarely determines a whole trait alone.
You can model and accurately.
Limit: E3 defines the classroom product or success criterion. It is not independent scientific evidence and cannot justify a clinical or causal claim.
PLTW-PBT-2026-10-26 · Simulated classroom evidence scenario
Your role: biomedical investigator
Decision: Your team must decide what the evidence from today's lesson supports before submitting the lab report named on today's page.
- • Hold the severity call until we learn whether people carrying this same change actually developed symptoms, since some never do.
- • Judge severity by where the change lands and how the amino acid's chemistry shifts, not by the change's size.
- • Rank your as severe, because every mutation harms the and a bigger change means a worse disease.
Response: State one choice, cite at least two evidence IDs, explain the rule that connects them, and add one limitation. Submit it as the lab report.
Claim ceiling: Today's evidence supports a classroom claim about today's lesson. It cannot prove causation, diagnose a real patient, or justify action outside this room.
Reason for review: Your team must decide what the evidence from today's lesson supports before submitting the lab report named on today's page.
Context: Building and with physical pieces makes the abstract central dogma concrete, so you can see the precise point where a single base change disrupts the .
- • T1: Read the modeling SOP and set up a DNA template strand.
- • T2: Transcribe the template into mRNA, recording each base pair.
- • T3: Translate the mRNA into an amino acid sequence using a codon chart.
- • T4: Introduce a point and re-translate to compare the .
- • T5: Record one limitation of the model and one source of error.
- • E1: Genetic evidence can support an inheritance, , sequence, or expression explanation, but penetrance, regulation, environment, family structure, and test uncertainty can limit the conclusion.
- • E2: Stored information can be copied, read, and converted into a functional product.
- • E3: You can model and accurately.
Measurements: No patient measurement is supplied unless it appears explicitly in E1-E3 or F1. Do not invent a value.
Figure finding: Teaching diagram for DNA and modeling. Trace the labeled observation or evidence sequence before choosing an explanation. This is a teaching model, not patient or experimental data.
Uncertainty: This is a composite classroom scenario. Missing history, measurements, or confirmation tests remain unknown and limit the conclusion.
- • The solution must address the stated need in today's lesson.
- • The decision must be supported by E1-E3.
- • The final product must make the success criteria visible.
- • Complete the work inside the 80-minute block.
- • Use only supplied or teacher-approved materials and evidence.
- • Do not trade , accessibility, or privacy for speed.
- • and evidence quality: must pass before scoring other criteria.
- • User need and effectiveness: highest scored criterion.
- • Time, cost, and ease of use: compare only after and effectiveness pass.
Test evidence: For each option, record the E1-E3 result that supports or fails each criterion. Do not assign a score without a named observation.
- Version or option tested
- Criterion met or missed
- Evidence ID and result
- Revision made
- Reason for the revision
- Need and user
- Criteria and constraints
- Chosen option and evidence
- Test result
- Revision and reason
Students often think Students often think mRNA is identical to the DNA template it was copied from, just with the same letters.. The trap: The trap is forgetting the base-pairing rules and the U-for-T swap. mRNA is complementary to the template, not a copy, and RNA uses uracil, so A on DNA gives U on mRNA. Get this wrong and every codon is wrong.
Lab notebook entry (Patient A gene model):
- Original DNA template (3'-5'): T A C A C C G A G
- mRNA (5'-3'): A U G U G G C U C
- Original amino acids (codon chart): Met (AUG, start) - Trp (UGG) - Leu (CUC)
- Point mutation introduced: DNA template ACC changed to ACA, so mRNA UGG becomes UGU
- Mutated amino acids: Met - Cys (UGU) - Leu
- Mutation type: missense. Justification: one base changed, which changed one codon, which changed one amino acid (Trp to Cys) without making a stop codon.
- Limitation: the model shows the amino acid sequence but cannot show how the protein folds in 3D, so it cannot prove how much function is lost.
| Version | mRNA codons | Amino acids |
|---|---|---|
| Original | AUG UGG CUC | Met Trp Leu |
| Mutated | AUG UGU CUC | Met Cys Leu |
| Change | UGG to UGU | Trp to Cys (missense) |
This model shows the level of evidence and organization needed to complete: A lab notebook entry showing the original DNA template, the mRNA, the original amino acid sequence with codon-chart citations, the mutated sequence, the mutation type with justification, and one model limitation.
- State the question and method.
- Present the observations and data with units.
- Explain the result, limitations, and next investigation.
Keep the structure. Replace the question, facts, measurements, and evidence. Then recheck units, vocabulary, and whether the conclusion goes beyond the evidence.
Also due today: Photograph the notebook entry and upload to the tracker before leaving class.
- CER:
- Claim, Evidence, Reasoning: make a claim, back it with evidence, explain your reasoning.
- SOP:
- Standard Operating Procedure, the exact steps to follow (especially in a lab).
- Tracker:
- Your PLTW progress log where you record completed evidence.
- myPLTW:
- The PLTW course site where you do the online activities. Find it in Clever with your Microsoft sign-in, right next to Schoology.
Tap the speaker to hear a term. Add two of these to your notebook glossary with a definition and an example in your own words.
Pick just 2 or 3 words from today and make them yours: write what each one means in your own words, name the context clue or evidence that helped, then give one example from what you actually did in DNA and protein modeling. Try your own words first; the glossary is there if you get stuck. This is voluntary and counts as extra credit, so keep it short.
Saved on this device. Show Mr. Mendoza or add these to your notebook glossary to claim the extra credit.
Hand-picked readings and interactives for this lesson, from authoritative open organizations and PLTW's own public course outline.
Practice: try a question, then check your answer▸
Claim ceiling for this check: Today's evidence supports a classroom claim about today's lesson. It cannot prove causation, diagnose a real patient, or justify action outside this room.
A DNA template strand reads 3'-TAC-5'. Transcribe it to an mRNA codon, then use a codon chart to name the amino acid. (TAC template gives the AUG start codon.)
Write an answer and pick a confidence to unlock the key.
Fast retrieval with instant answers, not the commit-then-reveal check above. Try each from memory first: write what you remember about the earlier units, then check yourself here.
Missed class or ready for more?▸
Run this before you touch the bench. It is built from the real lab procedure, so the decisions you make here are the ones you will make with the equipment in your hands.
I can name the procedure's purpose and the evidence I will record. I can state today's specific hazards and the control for each. If this deck does not name them, I ask Mr. Mendoza before I touch anything. My data table is ready before materials are handled.
Finish the checklist before you handle any material.
- • This is a paper/physical modeling activity; standard classroom safety applies.
- • If using plastic model kit pieces, do not put small pieces in your mouth and store all pieces in their labeled bag at the end of class.
- • Handle scissors with care; pass them closed, handle-first.
- • Return all model materials to the designated storage location at the end of class so they are available for subsequent periods.
- 1Before materials are handled, identify the purpose, variables or comparison, controls, measurement units, and stop-work condition.
- 2Read the modeling SOP and set up a DNA template strand.
- 3Transcribe the template into mRNA, recording each base pair.
- 4Translate the mRNA into an amino acid sequence using a codon chart.
- 5Introduce a point mutation and re-translate to compare the protein.
- 6Record one limitation of the model and one source of error.
- 7Record each result in the prepared table before interpreting it. Mark missing, repeated, or invalid results truthfully.
- 8Complete the named cleanup and waste route, remove PPE safely, wash hands when required, and confirm the station is ready for the next group.
| Trial or sample ID | Independent condition | Measured result with units | Observation before interpretation | Quality-control note |
|---|---|---|---|---|
Before the procedure, predict the result and cite the rule behind the prediction.
After the procedure, compare the result with the prediction and name one limitation or source of uncertainty.
What today's skills lead to. These are real health-science careers this course builds toward. Tap one to see, on the US Department of Labor's O*NET site, what the job actually involves, what it pays, and how fast it is growing.
Use the virtual DNA/ builder to transcribe and translate a gene, then introduce a point and record the changed protein with one stated limitation.
learn.genetics Genetics BasicsPhotograph your notebook entry and upload to the tracker before leaving class.
Class still runs. Complete the online activity above (it's self-guided). Need the concept taught without a teacher? Use this authoritative explainer:
Learn.Genetics (University of Utah): DNA to protein- CompleteEvery required part of the artifact is present, nothing left blank.
- AccurateThe science and the data are correct and match the evidence.
- Scientific reasoningYou explain your claim with evidence and reasoning (CER), not just an answer.
- Professional communicationClear, organized, labeled, and written the way a clinician or scientist would.
- SubmittedGo to Schoology to turn this in. Submit one PDF. Put your first and last name in the document header. Name the file: FirstName LastName - Assignment Title - YYYY-MM-DD.pdf. If you cannot get in, see Mr. Mendoza. Do not skip the work.
- Error analysis and method · counts doubleName a specific limit of the method and how it moved your result, and compare what you predicted to what happened. "Human error" does not count; say what about the procedure or instrument caused it.
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