Karyotype case analysis
Open your materials, follow the steps, then turn in your work.
Students individually arrange and interpret a karyotype to identify a chromosomal abnormality in a patient case.
1. Open your materials
Use the materials named in the first step below. Open lesson resources.
2. Start the work
Record the SOP for cutting, pairing, and ordering chromosome images.
Show all 5 required steps
- Record the SOP for cutting, pairing, and ordering chromosome images.
- Identify the independent and dependent variables in this diagnostic procedure.
- Sort chromosomes by size and centromere position into 22 pairs plus sex chromosomes.
- Compare the completed karyotype to a reference to detect any extra or missing chromosome.
- Name the abnormality and note one source of error that could affect the reading.
Lost your place? Lost your place? You should have the SOP recorded and your variables identified (steps 1-2). If so, keep sorting chromosomes into 22 pairs plus the sex pair (step 3), compare to the reference (step 4), then name the abnormality and one error source (step 5).
Check your work before submitting
- Produce a correctly ordered karyotype following the lab SOP.
- Identify the chromosomal abnormality and state one procedural limitation.
Before lab work: read the safety rules
- Handle scissors with blade pointing down when moving.
- Keep workspace clear of loose scraps to avoid contaminating another student's karyotype.
- Wash hands after handling printed lab materials.
3. Turn in your work
DueCheck Schoology- Hand in
- Completed karyotype template with labeled chromosome pairs, identified abnormality, and one stated procedural limitation.
How to submit and name your file
Turn in the mounted karyotype and your written abnormality statement to the collection tray before the period ends.
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: Genetic tests reveal permanent, shared family information, so decisions about testing must be governed by consent and privacy rather than by any single person's wishes. Today: A karyotype is a diagnostic tool whose result depends on following a precise SOP, so an error in cutting or pairing can produce a false diagnosis.
Check you have the right sheet: the top of it prints today's portal day, Karyotype case analysis. 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: A is a diagnostic tool whose result depends on following a precise SOP, so an error in cutting or pairing can produce a false diagnosis.
- 0-5 minReview SOP posted at station: cutting, pairing, and mounting sequence.
- 5-10 minIdentify and record ( images given) and (completed reading).
- 10-50 minIndividual construction: sort 22 autosome pairs plus sex chromosomes; mount on template.
- 50-65 minCompare to reference ; identify and name the chromosomal abnormality.
- 65-75 minRecord one source of procedural error that could affect the diagnosis.
- 75-80 minSubmit completed and written abnormality statement before leaving.
- • Today you are the clinical cytogenetics technician: your reading is what the will use.
- • Follow the SOP exactly, sequence matters just as it does in a real lab.
- • This is a Handling/Preparation/Storage/Disposal skill (WebXam 072110 strand 5): precision and documentation count.
- • When you identify the abnormality, write it down in proper clinical language.
- • Chromosomes are paired by homologs using size, banding pattern, and centromere position.
- • An extra or missing detected in a indicates a numerical abnormality.
- • Procedural errors in cutting, pairing, or image quality can produce a false reading.
PLTW connection and today's work
In myPLTW, open Lesson 2.2 Decoding a Diagnosis and go to Activity 2.2.4 Clues in the Chromosomes. Use its reference images to check your chromosome pairing.
Today's stopping point: You finished the chromosomal-abnormalities task Tuesday. Today you should reach the abnormality-identification question and submit it.
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.
Course connection
- Activity 2.2.4 Clues in the Chromosomes
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.
Genetic tests reveal permanent, shared family information, so decisions about testing must be governed by consent and privacy rather than by any single person's wishes.
A is a diagnostic tool whose result depends on following a precise SOP, so an error in cutting or pairing can produce a false diagnosis.
A research team lays out its question, variables, controls, sampling plan, measurement record, and analysis before deciding what the data support.
- Which variable is changed or compared?
- Which conditions and measurements must stay consistent?
- Which conclusion is inside the study's evidence boundary?
Define variables, controls, sampling, units, and the analysis plan before interpreting a result; analysis cannot repair biased or inconsistent measurement.
A well-organized classroom study can still be limited by , measurement quality, confounding, and the population represented.
- • Question and variable cards map to the study design.
- • Control and measurement cards map to fair, reproducible data collection.
- • The conclusion card maps to a bounded claim supported by the analysis.
Driving question: You are handed one patient's scrambled images. Following the SOP, can you arrange all 23 pairs and correctly name the abnormality without introducing your own error?
What you already know: Genetic tests reveal permanent, shared family information, so decisions about testing must be governed by consent and privacy rather than by any single person's wishes.
New idea: A is a diagnostic tool whose result depends on following a precise SOP, so an error in cutting or pairing can produce a false diagnosis.
Visual or model: F1. F1. A lesson illustration or teaching diagram for Karyotype case analysis. 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 case analysis.
- Organize the observation with a stable evidence ID.
- Apply this rule: Define variables, controls, sampling, units, and the analysis plan before interpreting a result; analysis cannot repair biased or inconsistent measurement.
- Choose the option the evidence supports and state the limit of the conclusion.
Real biomedical example: You are handed one patient's scrambled images. Following the SOP, can you arrange all 23 pairs and correctly name the abnormality without introducing your own error?
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.
- • : A photograph of a person's chromosomes arranged in pairs by size, used to spot missing, extra, or rearranged chromosomes.
- • inheritance: The passing of genetic traits from parents to offspring through genes carried on chromosomes during reproduction.
- • : 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.
- • : A person who carries one copy of a disease without showing symptoms but can pass it to their children.
- • 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.
- • : The increased chance of developing a disease that a person inherits because of specific gene variants passed down in their family.
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.
Define variables, controls, sampling, units, and the analysis plan before interpreting a result; analysis cannot repair biased or inconsistent measurement.
Limit: A well-organized classroom study can still be limited by , measurement quality, confounding, and the population represented.
Produce a correctly ordered following the lab SOP.
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-2026-11-04 · Simulated classroom evidence scenario
Your role: biomedical investigator
Decision: Your team must decide what the evidence from case analysis supports before submitting the lab report named on today's page.
- • Have a partner recheck your pairing before naming the abnormality, since a single misplaced creates a false diagnosis.
- • Pair chromosomes using banding pattern and centromere position along with size, then name the abnormality from the finished .
- • Match each to the pair closest in length, because once the size looks right the pair is right.
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 case analysis. 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 case analysis supports before submitting the lab report named on today's page.
Context: A diagnostic result is only as trustworthy as the standard procedure behind it, so recognizing sources of error is part of reading the result.
- • T1: Record the SOP for cutting, pairing, and ordering images.
- • T2: Identify the independent and dependent variables in this diagnostic procedure.
- • T3: Sort chromosomes by size and centromere position into 22 pairs plus sex chromosomes.
- • T4: Compare the completed to a reference to detect any extra or missing .
- • T5: Name the abnormality and note one source of error that could affect the reading.
- • 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: Define variables, controls, sampling, units, and the analysis plan before interpreting a result; analysis cannot repair biased or inconsistent measurement.
- • E3: Produce a correctly ordered following the lab SOP.
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 case analysis. 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 case analysis.
- • 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 that once a is 'about the right size' it belongs in that pair, so they stop checking after size.. The trap: Size alone is not enough; two chromosomes can be close in length but differ in banding pattern and centromere position. The trap is pairing by size only, which lets a misplaced slip through and produces a false reading.
Karyotype lab (Patient A):
- SOP followed: cut each chromosome image, sort by size (largest to smallest), align by centromere position and banding pattern, place into 22 numbered autosome pairs plus the sex pair.
- Variables: independent variable is the patient's chromosome images; dependent variable is the final pair count and arrangement.
- Result: 22 normal autosome pairs and XX, but chromosome 21 has three copies instead of two.
- Abnormality named: Trisomy 21 (Down syndrome).
- Procedural limitation: if two chromosomes have similar size and banding, I could mis-pair them, which would produce a false reading; poor image quality makes this worse.
This model shows the level of evidence and organization needed to complete: A finished karyotype template with chromosome pairs ordered per the SOP, the identified abnormality named, and one stated procedural 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: Turn in the mounted karyotype and the written abnormality statement to the collection tray before the period ends.
- 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 Karyotype case analysis. 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 case analysis. It cannot prove causation, diagnose a real patient, or justify action outside this room.
Your finished karyotype shows only one X and no second sex chromosome, giving 45 chromosomes total. Before you report it, what is one procedural error you must rule out?
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. This lesson has more than one, and they cover different skills.
I can name the procedure's purpose and the evidence I will record. I can name today's hazards and the control for each: Handle scissors with blade pointing down when moving. My data table is ready before materials are handled.
Finish the checklist before you handle any material.
- • Handle scissors with blade pointing down when moving.
- • Keep workspace clear of loose scraps to avoid contaminating another student's karyotype.
- • Wash hands after handling printed lab materials.
- 1Before materials are handled, identify the purpose, variables or comparison, controls, measurement units, and stop-work condition.
- 2Record the SOP for cutting, pairing, and ordering chromosome images.
- 3Identify the independent and dependent variables in this diagnostic procedure.
- 4Sort chromosomes by size and centromere position into 22 pairs plus sex chromosomes.
- 5Compare the completed karyotype to a reference to detect any extra or missing chromosome.
- 6Name the abnormality and note one source of error that could affect the reading.
- 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.
Today is individual work you can do from home: complete the same target above, then submit your Lab report.
Go 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.
Class still runs. Complete the online activity above (it's self-guided). Need the concept taught without a teacher? Use this authoritative explainer:
NHGRI: how to read a pedigree- 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.
This week
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