DNA and protein modeling
This page has four parts, in the order you use them. Part 1 is what you need to know. Part 2 says what to do, in plain English. Part 3 shows the work done once on a case that is not yours. Part 4 is your own work and where to turn it in.
Open your materials, follow the steps, then turn in your work.
Model transcription and translation following an SOP and predict what a mutation would do to 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▸
Part 1 of 4 · Background and definitions▸
💡 Big idea: Modeling and by hand makes each base pairing visible, so you can pinpoint exactly where one changed base rewrites the .
- • In , the template strand is read 3' to 5' and the mRNA is synthesized 5' to 3'; each 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 but produces the same amino acid (due to codon degeneracy); a mutation changes one amino acid; a mutation introduces a premature stop codon.
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 .
Driving question: When you transcribe and translate a real strand by the 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: No figure is attached to this lesson. The readings, the worked example and E1 to E3 carry the evidence.
- 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 strand by the and then change one base, what happens to the amino acid sequence, and why?
What the evidence supports: E1 to E3 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.
- • : 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 wrapped around proteins that carries genes; humans normally have 46 of them, arranged in 23 pairs.
- • gene: A stretch of 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 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. This is thinking practice for the one turn-in named under Turn in, not a second submission.
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.
Today's decision · 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 effect claim until the real is tested, because a hand-built model cannot show whether it works.
- • Build the mRNA complementary to the template with uracil replacing thymine, then read the codons for changes.
- • Copy the template letters straight across into the mRNA, since mRNA carries the same sequence the already stored.
Response: State one choice, cite at least two evidence IDs, explain the rule that connects them, and add one limitation. Use it inside the one turn-in named under Turn in; it is not a separate submission.
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 and copy the practice template strand in Part 2 of this page into your notebook.
- • T2: Transcribe the template into mRNA, recording each base pair.
- • T3: Translate the mRNA into an amino acid sequence using a codon chart.
- • T4: Predict, in one sentence, what a single base change could do to the ; the runs are next class, on the day-2 sheet.
- • 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. Do not invent a value.
Uncertainty: This is a composite classroom scenario. Missing history, measurements, or confirmation tests remain unknown and limit the conclusion.
Students often think mRNA is identical to the template it was copied from, just with the same letters. The trap: 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 gives U on mRNA. Get this wrong and every codon is wrong.
- 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.
Part 2 of 4 · Directions in plain English▸
2.1 Open your materials
Use the materials named in the first step below. Open lesson resources.
Practice template strand (made up for practice, not from any case or patient)
DNA template strand, read 3' to 5'
- 3' G C T A C G T G C C A A A T C T C A C T 5'
- Transcribe it into mRNA (5' to 3'), find the first AUG, bracket the codons from there, then translate with your codon chart until you reach a stop codon.
2.2 Start the work
Read the modeling SOP and copy the practice template strand in Part 2 of this page into your notebook.
Show all 5 required steps
- Read the modeling SOP and copy the practice template strand in Part 2 of this page into your notebook.
- Transcribe the template into mRNA, recording each base pair.
- Translate the mRNA into an amino acid sequence using a codon chart.
- Predict, in one sentence, what a single base change could do to the protein; the mutation runs are next class, on the day-2 sheet.
- Record one limitation of the model and one source of error.
Lost your place? Check the SOP: (1) template set up, (2) mRNA transcribed, (3) amino acids read from the codon chart, (4) your one-sentence prediction written. Restart at your last completed step, then log one limitation and one source of error.
- 0:00Quick start: copy the practice template strand from this page; check the 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
- 0:38Prediction: write one sentence on what a single base change could do to the ; check your against a partner
- 0:56Read the six jobs on your sheet and write one sentence connecting a protein to its job
- 1:05Record one model limitation and one source of error; preview the analysis lesson that follows
- • Today you are going to physically model the central dogma. You will use the practice template strand on this page, transcribe it to mRNA base by base, and translate it to an amino acid sequence codon by codon.
- • The codon chart is your decoder ring. Every three bases in the mRNA are one codon. AUG codes for methionine and also signals where starts. Only the three stop codons (UAA, UAG, UGA) do not code for an amino acid; they end the chain. Know those before you start.
- • The runs are next class, on the day-2 sheet. Today is the process done right, because a wrong makes every mutation run meaningless.
- • Read the 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.
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 amino acid sequence there if it opens.
Today's stopping point: By the end of today the original sequence should be transcribed and translated correctly in your notebook, with your prediction written.
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 in Part 4 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.
Part 3 of 4 · Worked example▸
This is a parallel case, not your own. Read it for the order of the work, then do your own in Part 4.
Lab notebook entry (a practice template, not today's strand):
- Original DNA template (3'-5'): T A C A C C G A G A T T
- mRNA (5'-3'): A U G U G G C U C U A A
- Start codon marked: AUG, with every codon bracketed from there before any lookup.
- Amino acids (codon chart): Met (AUG, start) - Trp (UGG) - Leu (CUC) - stop (UAA, no amino acid)
- Prediction: if one base in the UGG codon changed, the chain would get a different second amino acid, or end early if the new codon were a stop codon (UGA or UAG). UGG is the only codon for Trp, so no change there can be silent. The runs on the Analyze the mutation day test this.
- Limitation: the model shows the amino acid sequence but cannot show how the protein folds in 3D, so it cannot show what the chain does.
| Molecule | Sequence |
|---|---|
| DNA template (3' to 5') | TAC ACC GAG ATT |
| mRNA (5' to 3') | AUG UGG CUC UAA |
| Amino acids | Met Trp Leu (stop) |
This model shows the level of evidence and organization needed to complete: A lab notebook entry showing the original DNA template, the mRNA, the marked start codon, the amino acid sequence with codon-chart citations, a one-sentence prediction of what a single changed base could do, 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 your notebook entry and submit it as one PDF to Schoology assignment for this lesson in Schoology before leaving class.
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 .
- • Working copy maps to RNA.
- • Production output maps to or a regulated cell function.
Part 4 of 4 · Your work▸
Check your work before submitting
- I can model transcription and translation accurately.
- I can predict what a mutation could do to 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.
4.1 Turn in your work
DueCheck the Schoology assignment for this day- Hand in
- Lab notebook entry: original DNA template strand, mRNA transcription, original amino acid sequence (with codon chart citations), your one-sentence prediction of what a base change would do, and one model limitation.
How to submit and name your file
Photograph your notebook entry and submit it as one PDF to the Schoology assignment for this lesson in Schoology 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.
PDF upload helpYou get two school days for every day you were absent, so this deadline moves with you.
Today's lesson is in Schoology
Each school day has one lesson page in Schoology that holds everything for the day: the goal, the story so far, every table and data value, the numbered steps, and what to turn in. Open it first and work from it. The other rows for this day, if any, are the score line for a paper quiz or test and the John Carroll debate item; they do not add work. Check Schoology for each deadline.
- Today's Lesson · Mon 10/26 · Wk10 · Research your patient's condition, then plan the first visit(today's lesson page: the goal, the data, the steps, and what to turn in are all on it)
Link will not open? Open Schoology, choose your course and section, and find the title shown above.
- 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. Schoology attaches your name to your upload; on the page itself, write your period and code. 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.
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.
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.
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?▸
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 copy the practice template strand in Part 2 of this page into your notebook.
- 3Transcribe the template into mRNA, recording each base pair.
- 4Translate the mRNA into an amino acid sequence using a codon chart.
- 5Predict, in one sentence, what a single base change could do to the protein; the mutation runs are next class, on the day-2 sheet.
- 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.
| Which trial or sample this row is | What you changed on purpose | What you measured, with units | What you saw, before you explain it | Anything that could make this reading wrong |
|---|---|---|---|---|
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 Learn.Genetics transcribe-and-translate page to transcribe and translate a gene, then predict in one sentence what one base change would do, with one stated limitation.
Learn.Genetics: Transcribe and translate a genePhotograph your notebook entry and submit it as one PDF to the Schoology assignment for this lesson in Schoology before leaving class.
Class still runs. Complete today's work as this page describes (it is self-guided). Need the concept taught without a teacher? Use this authoritative explainer:
Learn.Genetics (University of Utah): DNA to proteinSources: slides, readings, and resources▸
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.
Hand-picked readings and interactives for this lesson, from authoritative open organizations and PLTW's own public course outline.
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