SNP and PTC case
Safety gate · before any work
- Wear the required PPE, keep the bench clear, handle equipment only as directed, and know where the eyewash, sink, and spill kit are before you start.
- Human samples and data stay private: label with a code, never a name, and dispose of materials in the correct waste container, then wash your hands.
Do now
Connect a single-nucleotide polymorphism to a phenotype using the PTC-tasting genotype dataset.
- Hand in
- Genotype-to-phenotype table for three individuals (homozygous/heterozygous labeled) and a written carrier prediction.
- Where
- Turn this in at the drop folder with your district Microsoft sign-in, or hand it to Mr. Mendoza in class. Both count as submitted. Doing the activity in myPLTW does not.
You get two school days for every day you were absent, so this deadline moves with you.
In the TAS2R38 dataset, why do some people gag on a PTC test strip while others taste nothing at all, when the difference between them comes down to a single swapped nucleotide?
Connect a single-nucleotide polymorphism to a phenotype using the PTC-tasting dataset.
- • You'll be able to read a SNP and pair it to a phenotype.
- • You'll be able to predict status from data.
- A SNP is a change at how many of DNA: one, ten, or a whole gene?
- If the tasting is dominant, would a heterozygous person taste PTC or not?
- 1Open the teacher dataset in the shell and find the SNP column for the PTC-tasting gene.
- 2For three people, write their next to their phenotype and mark homozygous or heterozygous.
- 3Decide whether the tasting tracks with the trait and write one sentence of evidence.
- 4Predict the status of one labeled person using language.
- 5Submit your -to-phenotype table and prediction as your daily evidence.
What did this day actually feel like?
SNP and PTC case
LAB A small DNA difference changing a real trait, using the PTC tasting case. Most of whether you taste it comes down to three linked base positions in one gene, TAS2R38, inherited together as a set. Even then it is not clean.
Some people fall between taster and non-taster.
The size of the change against the size of the effect is the thing that gets you.
Turned in: data table → Data Tables folder
Fiction. There is no such student. The lessons, labs and dates are the real planned course; the student, the classmates and the conversations are invented.
The same day, drawn.
A small DNA difference changing a real trait, using the PTC tasting case. Most of whether you taste it comes down to three linked base positions in one gene, TAS2R38, inherited together as a set.
Fiction. There is no such student. The lessons, labs and dates are the real planned course; the student, the classmates and the conversations are invented.
🛠 Get unstuck · pick your level
Lab day: Tier 1 is the whole class at the bench. No extension today.
🔑 Today's words · 5
Tap a word in the lesson for a plain meaning and one example. Recycled into next week's Do-Now.
Do the work · 80-minute blockfirst 5 min = hook▸
💡 Big idea: A single-nucleotide change in TAS2R38 alters the bitter-taste , so one DNA letter decides whether PTC tastes bitter or like nothing at all.
- 0-8Hook: PTC tasting demo or description; introduce SNP vocabulary
- 8-25Open dataset; locate SNP column; record and phenotype for three individuals
- 25-40Mark each as homozygous or heterozygous; decide if tasting tracks phenotype
- 40-55Write one evidence sentence; predict status for one labeled person
- 55-70Partner check: verify language and logic
- 70-80Submit table and prediction to the class site
- • Hook: Pass around PTC strips (if available) or describe the tasting phenotype; ask who tasted bitterness.
- • Why it matters: This same SNP-to-phenotype logic underlies pharmacogenomics, where one DNA letter determines drug response.
- • Today's work: You read a real dataset and connect alleles to phenotypes the same way a lab does.
- • Exit goal: -to-phenotype table and prediction submitted before the bell.
- • A SNP is a single base-pair variation at a specific ; millions exist across the human genome.
- • The TAS2R38 gene has a common SNP that distinguishes tasters from non-tasters of phenylthiocarbamide (PTC).
- • Homozygous dominant and heterozygous individuals express the taster phenotype; homozygous recessive individuals do not.
Inheritance review, pedigree logic, SNPs, genetic counseling, and the MP1 data inflection. · SNP and PTC case
Day 3 of this lesson. Open this exact section in myPLTW (find it in Clever, Microsoft sign-in), then do the work below.
Do this: Open Activity 2.1.3 Test Your Own Genes in myPLTW and use the teacher dataset to connect SNP alleles to phenotypes.
Mark the SNP activity complete after your -to-phenotype table and prediction are submitted.
Pedigree should be done (Tuesday); SNP table and prediction due today.
-to-phenotype table with homozygous/heterozygous labels and prediction submitted.
The official PLTW activity stays inside myPLTW. If myPLTW will not open, use F1 and E1-E3 on this page to complete today's local evidence decision, then make up the official activity when access returns. Turn this in at the drop folder with your district Microsoft sign-in, or hand it to Mr. Mendoza in class. Both count as submitted. Doing the activity in myPLTW does not.
Check things off as you work, then submit. This tells Mr. Mendoza how you're doing so he can help the class. It does not replace turning in your producible through the submission route shown below.
Use the code Mr. Mendoza gave you, not your name. Saved on this device.
Inheritance review, pedigree logic, SNPs, genetic counseling, and the MP1 data inflection. · SNP and PTC case
Open Activity 2.1.3 Test Your Own Genes in myPLTW and use the teacher dataset to connect SNP alleles to phenotypes.
Pedigree should be done (Tuesday); SNP table and prediction due today.
This is how Mr. Mendoza sees the class keeping pace with PLTW. Be honest, it only helps if it is accurate.
🎯 Connect a single-nucleotide polymorphism to a phenotype using the PTC-tasting dataset.
- Open the teacher dataset in the shell and find the SNP column for the PTC-tasting gene.
- For three people, write their next to their phenotype and mark homozygous or heterozygous.
- Decide whether the tasting tracks with the trait and write one sentence of evidence.
- Predict the status of one labeled person using language.
- Submit your -to-phenotype table and prediction as your daily evidence.
Data table: -to-phenotype table for three individuals (homozygous/heterozygous labeled) and a written prediction.
Turn this in at the drop folder with your district Microsoft sign-in, or hand it to Mr. Mendoza in class. Both count as submitted. Doing the activity in myPLTW does not. Use the checklist just below and upload by 11:29 PM for full credit. Absent with an excused absence? You get two school days for every day you were absent, so this deadline moves with you.
| Task | Who |
|---|---|
| Open the teacher dataset in the shell and find the SNP column for the PTC-tasting gene. | _______ |
| For three people, write their next to their phenotype and mark homozygous or heterozygous. | _______ |
| Decide whether the tasting tracks with the trait and write one sentence of evidence. | _______ |
| Predict the status of one labeled person using language. | _______ |
| Submit your -to-phenotype table and prediction as your daily evidence. | _______ |
Working solo? Put your own name in "Who" for every row.
- You'll be able to read a SNP and pair it to a phenotype.
- You'll be able to predict status from data.
- 1Do thisConnect a single-nucleotide polymorphism to a phenotype using the PTC-tasting genotype dataset.
- 2Use this resource
- 3Submit thisData table: Genotype-to-phenotype table for three individuals (homozygous/heterozygous labeled) and a written carrier prediction.
- 4Submit it here
- 1Open the drop folder.
- 2Sign in with your district Microsoft account, not a personal one.
- 3Upload the file, named Lastname_Firstname__Assignment Title.
- 4Your own upload panel says Uploaded with a green check: that is your receipt.
Turn this in at the drop folder with your district Microsoft sign-in, or hand it to Mr. Mendoza in class. Both count as submitted. Doing the activity in myPLTW does not. Genetics of Disease (Medical Interventions) › Inheritance review, pedigree logic, SNPs, genetic counseling, and the MP1 data inflection. › Data tableOpen the drop folder
Learn it · deck, reading, 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.
Two unaffected parents can each carry a silent recessive , so an affected child appearing from healthy parents is proof the trait is recessive, not a break in the family tree.
A single-nucleotide change in TAS2R38 alters the bitter-taste , so one DNA letter decides whether PTC tastes bitter or like nothing at all.
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: In the TAS2R38 dataset, why do some people gag on a PTC test strip while others taste nothing at all, when the difference between them comes down to a single swapped nucleotide?
What you already know: Two unaffected parents can each carry a silent recessive , so an affected child appearing from healthy parents is proof the trait is recessive, not a break in the family tree.
New idea: A single-nucleotide change in TAS2R38 alters the bitter-taste , so one DNA letter decides whether PTC tastes bitter or like nothing at all.
Visual or model: F1. F1. A lesson illustration or teaching diagram for SNP and PTC case. Use it with E1-E3; it is a model or context image, not experimental or patient data. What to notice: Trace the labeled testing, treatment, or biological process and identify where evidence limits the decision.
- Observe or measure the relevant feature in SNP and PTC case.
- 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: In the TAS2R38 dataset, why do some people gag on a PTC test strip while others taste nothing at all, when the difference between them comes down to a single swapped nucleotide?
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.
- • : One of the alternative versions of a gene found at the same spot on a , like the blue or brown options for eye color.
- • : The specific set of gene versions an individual carries, which works with the environment to shape observable traits.
- • phenotype: The observable traits of an organism, such as appearance or function, that result from its combined with environmental influences.
- • pedigree: A family tree drawn with standard symbols (squares for males, circles for females, filled for affected) so any geneticist can read a family at a glance.
- • SNP: A single-nucleotide polymorphism, a one-letter difference in DNA at a specific spot that varies between people.
- • : A person who carries one copy of a disease without showing symptoms but can pass it to their children.
- • : A guided conversation with a trained specialist who explains inherited disease risks, test options, and choices to help a family make informed decisions.
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.
A SNP is a single base-pair variation at a specific ; millions exist across the human genome.
Limit: E1 supplies context or an observation; it does not by itself establish the explanation.
A single-nucleotide change in TAS2R38 alters the bitter-taste , so one DNA letter decides whether PTC tastes bitter or like nothing at all.
Limit: E2 is a teaching statement or comparison and must be checked against the task evidence.
You'll be able to read a SNP and pair it to a phenotype.
Limit: E3 supports only the result or product criterion named here; it cannot justify a broader clinical or causal claim.
PLTW-GEND-2026-10-14 · Simulated classroom evidence scenario
Your role: medical interventions team member
Decision: Your team must decide what the evidence from SNP and PTC case supports before submitting the labeled and result claim named on the lesson page.
- • Choose the strongest supported explanation.
- • Choose the next evidence to collect.
- • Hold the decision because the evidence is insufficient.
Response: State one choice, cite at least two evidence IDs, explain the rule that connects them, and add one limitation. Submit it as the labeled and result claim.
Claim ceiling: The supplied lesson evidence can support an observation, pattern, classroom mechanism, or next-step decision about SNP and PTC case. It cannot by itself prove causation, establish a real clinical diagnosis, or justify action outside this classroom task.
Reason for review: Your team must decide what the evidence from SNP and PTC case supports before submitting the labeled and result claim named on the lesson page.
Context: One base-pair change at the right spot can flip a phenotype, because a single nucleotide polymorphism can alter the a gene builds, and that is why individual DNA letters, not just whole genes, matter for who we are.
- • T1: Open the teacher dataset in the shell and find the SNP column for the PTC-tasting gene.
- • T2: For three people, write their next to their phenotype and mark homozygous or heterozygous.
- • T3: Decide whether the tasting tracks with the trait and write one sentence of evidence.
- • T4: Predict the status of one labeled person using language.
- • T5: Submit your -to-phenotype table and prediction as your daily evidence.
- • E1: A SNP is a single base-pair variation at a specific ; millions exist across the human genome.
- • E2: A single-nucleotide change in TAS2R38 alters the bitter-taste , so one DNA letter decides whether PTC tastes bitter or like nothing at all.
- • E3: You'll be able to read a SNP and pair it to a phenotype.
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 SNP and PTC case. Trace the labeled testing, treatment, or biological process and identify where evidence limits the decision. 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.
Students often think Students think a non-taster must have 'no gene' for tasting, or that the difference is a large deletion, because they assume big phenotype differences require big DNA differences.. The trap: Both tasters and non-tasters have the TAS2R38 gene. The difference is a single base-pair swap (a SNP), not a missing gene. Expecting a huge DNA change for a clear trait will make you misread the dataset, where the only difference between the two phenotypes is one letter.
I found the SNP column for the TAS2R38 PTC-tasting gene and matched each person's genotype to their tasting phenotype. I used T for the taster allele and t for the non-taster allele.
Does the tasting allele track with the trait? Yes. Everyone with at least one T allele tasted PTC, and the only non-taster was homozygous tt. Evidence: Person 1 (TT) and Person 2 (Tt) both tasted; Person 3 (tt) did not, so the T allele tracks with tasting and behaves as dominant.
Carrier prediction: Person 2 is a heterozygous taster (Tt). They show the taster phenotype but carry one non-taster allele, so they could pass the non-taster allele to a child.
| Person | Genotype | Zygosity | Phenotype |
|---|---|---|---|
| 1 | TT | homozygous | taster |
| 2 | Tt | heterozygous | taster |
| 3 | tt | homozygous | non-taster |
This model shows the level of evidence and organization needed to complete: Completes the SNP case analysis: a genotype-to-phenotype table for three individuals with homozygous or heterozygous labels, an evidence sentence, and a carrier prediction.
- Name the variables and include units.
- Enter observations without changing the raw values.
- Check labels, calculations, and patterns before interpreting the data.
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: Submit your genotype-to-phenotype table and prediction to the class site.
- 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 SNP and PTC case. 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.
Classroom documents for this lesson are posted in Schoology. Open Clever, then Schoology, and find each one by the name shown on its card.
Use this after the required lesson work when you are ready for a harder application or a deeper connection.
Placement rationale
Matched Genetic testing, PTC, pedigree, SNPs by path:Medical-Interventions/Unit-2_How-to-Screen-Your-Genes/2.1_Genetic-Testing-and-Screening; keywords:genetic testing, screening, ptc. Score 150. Visibility: student-schoology (student-facing resource; link through Schoology rather than local path).
Use this as the classroom resource for Genetic testing, PTC, pedigree, SNPs.
Placement rationale
Matched Genetic testing, PTC, pedigree, SNPs by path:Medical-Interventions/Unit-2_How-to-Screen-Your-Genes/2.1_Genetic-Testing-and-Screening; keywords:genetic testing, screening, snp. Score 146. Visibility: student-schoology (student-facing resource; link through Schoology rather than local path).
Use this if you were absent, got stuck, or need another pass before you submit the lesson artifact.
Placement rationale
Matched Genetic testing, PTC, pedigree, SNPs by path:Medical-Interventions/Unit-2_How-to-Screen-Your-Genes/2.1_Genetic-Testing-and-Screening; keywords:genetic testing, screening. Score 142. Visibility: student-schoology (student-facing resource; link through Schoology rather than local path).
How to get there: open Clever and sign in with your Microsoft (district) account. Both myPLTW and Schoology are in Clever. Do the activity in myPLTW. Turn the work in on this site or hand it to Mr. Mendoza, because that is the step that counts as submitted. Schoology only shows your report-card grade later.
Check yourself · commit, then reveal▸
Claim ceiling for this check: The supplied lesson evidence can support an observation, pattern, classroom mechanism, or next-step decision about SNP and PTC case. It cannot by itself prove causation, establish a real clinical diagnosis, or justify action outside this classroom task.
A person's TAS2R38 genotype is heterozygous (one taster allele, one non-taster allele). Will they taste PTC, and are they a carrier of the non-taster allele?
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.
Go further and get help▸
I can name the procedure's purpose and the evidence I will record. I can identify each named hazard and the control that reduces it: Wear the required PPE, keep the bench clear, handle equipment only as directed, and know where the eyewash, sink, and spill kit are before you start. My data table is ready before materials are handled.
Finish the checklist before you handle any material.
- • Wear the required PPE, keep the bench clear, handle equipment only as directed, and know where the eyewash, sink, and spill kit are before you start.
- • Human samples and data stay private: label with a code, never a name, and dispose of materials in the correct waste container, then wash your hands.
- 1Before materials are handled, identify the purpose, variables or comparison, controls, measurement units, and stop-work condition.
- 2Open the teacher genotype dataset in the shell and find the SNP column for the PTC-tasting gene.
- 3For three people, write their genotype next to their phenotype and mark homozygous or heterozygous.
- 4Decide whether the tasting allele tracks with the trait and write one sentence of evidence.
- 5Predict the carrier status of one labeled person using allele language.
- 6Submit your genotype-to-phenotype table and prediction as your daily evidence.
- 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.
From home, use the provided teacher dataset to complete the same case: build the genotype-to-phenotype table for three people and predict one person's status with a written explanation.
Teacher genotype dataset (PLTW course shell)Then submit your Data table. Turn this in at the drop folder with your district Microsoft sign-in, or hand it to Mr. Mendoza in class. Both count as submitted. Doing the activity in myPLTW does not.
Class still runs. Complete the online activity above (it's self-guided). Need the concept taught without a teacher? Use this authoritative explainer:
MedlinePlus: What is genetic testing?- 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.
- SubmittedTurned in the right way, on the class site or handed to Mr. Mendoza in class, and confirmed. Not in Schoology: that is where the report-card grade appears later.
- 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.