Microarray introduction
Open your materials, follow the steps, then turn in your work.
Explain how a microarray uses hybridization to test many genes at once and where it differs from PCR.
1. Open your materials
Use the materials named in the first step below. Open lesson resources.
2. Start the work
Define hybridization and explain how a labeled sample binds to spots on a microarray.
Show all 5 required steps
- Define hybridization and explain how a labeled sample binds to spots on a microarray.
- Describe what a colored spot versus a dark spot tells you about a gene.
- Compare in one row each: PCR, gel, and microarray, listing what each method is best for.
- Write one limit of microarrays that gel or PCR does not share.
- Submit your method comparison as your daily evidence.
Lost your place? Check which steps are done: hybridization defined, bright versus dark spot explained, the PCR-gel-microarray comparison row filled in, and one microarray limitation written. Pick up at the first one missing.
Check your work before submitting
- You'll be able to explain how a microarray reads many genes by hybridization.
- You'll be able to compare PCR, gel, and microarray by purpose and limit.
3. Turn in your work
DueCheck Schoology- Hand in
- Three-row method comparison table (PCR, gel, microarray) plus one sentence on a microarray limit not shared by the other two methods.
How to submit and name your file
Use the submission route shown on today's page.
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: Agarose acts as a sieve and DNA is pulled by charge, so smaller fragments travel farther and band position becomes a readable size map. Today: A microarray reads fluorescence where sample DNA hybridizes to matching probes, so one chip can report the expression of thousands of genes at once.
Optional: listen or watch a unit review▸
Need help? Warm-up, timing, and directions▸
💡 Big idea: A reads fluorescence where sample DNA hybridizes to matching probes, so one chip can report the expression of thousands of genes at once.
- 0-8Hook: image; introduce concept
- 8-25Define ; explain spot color as expression signal
- 25-50Build comparison table: PCR, gel, (purpose, scale, limit, output)
- 50-65Write one limit of microarrays not shared by PCR or gel
- 65-75Partner quiz: cover one column; name the method from description
- 75-80Submit comparison table to the class site; review for Friday quiz
- • Hook: Show a image and ask: how many tests do you think this represents? (answer: tens of thousands).
- • Why it matters: Microarrays accelerated genomics by shifting from one-gene-at-a-time to genome-wide profiling.
- • Today's work: You build a comparison table that will be your study reference for Friday's quiz.
- • Exit goal: Method comparison table with one limit submitted before the bell.
- • : fluorescently labeled cDNA from a sample binds to complementary probe sequences on the chip; fluorescence indicates which genes are expressed.
- • A bright spot means the gene is expressed (mRNA present in sample); a dark spot means little or no expression.
- • Microarrays survey thousands of genes at once but require specialized equipment and bioinformatics; PCR is targeted and gel is the readout, not a scanner.
PLTW connection and today's work
Open Activity 3.1.4 DNA Microarray in myPLTW and build your PCR-gel-microarray method comparison table.
Today's stopping point: Gel data table should be done (Wednesday); method comparison table due today.
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
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.
acts as a sieve and DNA is pulled by charge, so smaller fragments travel farther and band position becomes a readable size map.
A reads fluorescence where sample DNA hybridizes to matching probes, so one chip can report the expression of thousands of genes at once.
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: PCR and a gel handle one target at a time. How does a chip the size of a stamp test thousands of genes in a single run?
What you already know: acts as a sieve and DNA is pulled by charge, so smaller fragments travel farther and band position becomes a readable size map.
New idea: A reads fluorescence where sample DNA hybridizes to matching probes, so one chip can report the expression of thousands of genes at once.
Visual or model: F1. F1. A lesson illustration or teaching diagram for Microarray introduction. 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 introduction.
- 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: Genetic-testing teams audit whether consent, sample identity, result interpretation, and follow-up evidence are documented before a result informs the . Source: MedlinePlus: What is genetic testing?.
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 short single strand of DNA that binds to a target sequence and gives DNA polymerase a starting point to build a new strand, as in PCR.
- • : A bacterial that cuts DNA at a specific sequence, leaving clean or sticky ends used to splice genes together.
- • : A lab method that uses an electric field to pull DNA fragments through a gel so they separate by size and show up as bands.
- • : A chip holding thousands of tiny DNA spots that lets scientists measure the activity of many genes at once by detecting which spots light up.
- • : The pairing of two single DNA or RNA strands with matching base sequences into a double strand, used in tests to detect a specific gene.
- • marker: A measurable feature, molecule, or gene used to identify a cell, organism, or condition, like a flag that signals something specific.
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 gene-expression comparison describes relative signal patterns across the supplied conditions, and interpretation depends on normalization, replication, controls, measurement range, and the difference between association and causation.
Limit: A classroom expression table can support a bounded pattern claim but cannot diagnose disease, prove a regulatory mechanism, or establish clinical significance.
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 explain how a reads many genes by .
Limit: E3 defines the classroom product or success criterion. It is not independent scientific evidence and cannot justify a clinical or causal claim.
PLTW-GEND-2026-10-26 · Simulated classroom evidence scenario
Your role: medical interventions team member
Decision: Your team must decide what the evidence from introduction supports before submitting the vocabulary application named on today's page.
- • Check the controls and replicates before calling a bright spot a real expression difference between the supplied conditions.
- • Explain each glowing spot as sample DNA hybridizing to a matching probe, which reports the genes expressed in that sample.
- • Treat the as a faster gel whose colored spots report the size of each DNA fragment in the sample.
Response: State one choice, cite at least two evidence IDs, explain the rule that connects them, and add one limitation. Submit it as the vocabulary application.
Claim ceiling: Today's evidence supports a classroom claim about introduction. It cannot prove causation, diagnose a real patient, or justify action outside this room.
Mean = sum of values / number of values. Median = middle ordered value. Range = maximum - minimum.
For 2, 4, 4, and 10: mean = 20 / 4 = 5, median = 4, and range = 10 - 2 = 8.
Mean, median, and range keep the measurement unit. Order the values before finding the median.
Calculate the requested summary for today's supplied values, then write what it reveals and what it hides.
Students often think Students often think a is just a faster version of a gel, or that the colored spots show the size of DNA fragments the way gel bands do.. The trap: A does not measure size at all. Its spots report which genes are expressed based on where labeled sample binds by complementary . Confusing it with a gel means you miss that a microarray answers what is expressed, not how big the fragment is.
Hybridization in my words: A microarray is covered with single-stranded probe sequences. A labeled sample of DNA or cDNA washes over it, and each piece sticks (hybridizes) only where it finds its complementary probe. A bright, colored spot means that gene's sequence was present in the sample; a dark spot means it was not.
Method comparison: I compared PCR, gel, and microarray by what each is best for.
Microarray limit not shared by the others: A microarray needs specialized scanning equipment and bioinformatics software to read thousands of spots, while a PCR product or a gel can be set up and read with much simpler tools.
| Method | Best for | Output |
|---|---|---|
| PCR | Amplifying one target sequence | Many copies of one region |
| Gel | Separating fragments by size | Bands showing fragment sizes |
| Microarray | Surveying thousands of genes at once | Spot pattern showing expression |
This model shows the level of evidence and organization needed to complete: Completes the methods comparison: a three-row table contrasting PCR, gel, and microarray by purpose plus one sentence on a microarray limit the others do not share.
- Define the term in plain scientific language.
- Connect it to the current investigation.
- Use it accurately in a new example or contrast.
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 comparison table to Schoology.
- 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 Microarray introduction. 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.
Open this when the class reaches this activity and use it to complete the required lesson artifact.
Placement rationale
Matched PCR, , microarrays by path:Medical-Interventions/Unit-2_How-to-Screen-Your-Genes/2.1_Genetic-Testing-and-Screening; keywords:pcr, gel electrophoresis. Score 142. 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 PCR, , microarrays by path:Medical-Interventions/Unit-2_How-to-Screen-Your-Genes/00_Unit-Overview; keywords:pcr, gel electrophoresis. Score 138. Visibility: student-schoology (student-facing resource; link through Schoology rather than local path).
Use this after the required lesson work when you are ready for a harder application or a deeper connection.
Placement rationale
Matched PCR, , microarrays by path:Medical-Interventions/Unit-2_How-to-Screen-Your-Genes/2.1_Genetic-Testing-and-Screening; keywords:gel electrophoresis. Score 134. Visibility: student-schoology (student-facing resource; link through Schoology rather than local path).
Sign in to Clever with your district Microsoft account to open Schoology or myPLTW. Follow today's posted steps. If myPLTW will not open, use the posted alternative and tell Mr. Mendoza. Turn in your completed work through the Schoology assignment.
Practice: try a question, then check your answer▸
Claim ceiling for this check: Today's evidence supports a classroom claim about introduction. It cannot prove causation, diagnose a real patient, or justify action outside this room.
On a microarray, a spot for a gene glows bright. What does that tell you about that gene in the sample, and what does the brightness come from?
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.
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 to test how conserved IRF6 is across humans, mice, and zebrafish.
Goes with: BLAST: is IRF6 conserved across species?
Search ClinVar for which IRF6 changes are known to cause disease.
Goes with: ClinVar: which IRF6 changes cause disease?
The bench work needs equipment you do not have at home. Do the thinking half now: read the procedure, write your prediction, and set up your data table so it is ready.
Back in class. Ask Mr. Mendoza for the class data set, or for a bench slot to run it yourself. Do not submit a Vocabulary task with invented numbers.
Class still runs. Complete the online activity above (it's self-guided). Need the concept taught without a teacher? Use this authoritative explainer:
Genetic Science Learning Center: Gel ElectrophoresisYou've passed Unit 2, so the optional extra-credit track is open. Complete reserved-unit work from home, including virtual labs, for extra credit. Each item shows its correct submission route.
Open the extra-credit track- 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.
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