DNA sequencing basics
Explain how DNA sequencing reads the order of bases and why that sequence can act as a fingerprint for an organism.
Notebook entry: four DNA bases with pairing rules, two-sentence sequencing summary, and one question for the BLAST lab.
- 1Do thisExplain how DNA sequencing reads the order of bases and why that sequence can act as a fingerprint for an organism.
- 2Use this resource
- 3Submit thisVocabulary task: Notebook entry: four DNA bases with pairing rules, two-sentence sequencing summary, and one question for the BLAST lab.
- 4Submit it here
- 1CMSD website. Go to clevelandmetroschools.org and click the Clever button.
- 2Clever. Clever opens. Sign in if it asks.
- 3Microsoft (district) login. Use your district Microsoft account (the one for school).
- 4Schoology. Open Schoology, then your class, then Assignments, and find the file named below.
The file to submit is named: Genetics of Disease (Medical Interventions) › DNA identification, sequencing, BLAST, controls, query coverage, and E-value. › Vocabulary taskOpen Schoology
What counts as evidence, and where to find it
What makes evidence strong, and where do you find evidence you can trust?
Evidence is the data and observations you use to back up a claim. In science that means measurements, experimental results, images, and records, not “my friend said” or “I saw it once.”
Strong evidence is relevant (it actually bears on the claim), sufficient (there is enough of it), and reliable (it was collected carefully and others could repeat it). One data point is rarely enough; a pattern across many is far stronger.
Where you find it matters. Prefer primary sources and reputable ones: peer-reviewed studies, government and health agencies (CDC, NIH, NHGRI), and your own lab data. When you find a source online, do not trust it on looks. Check who is behind it and what better sources say.
- • Relevant: it directly supports (or tests) the claim.
- • Sufficient: there is enough of it, not a single lucky data point.
- • Reliable: collected carefully, and others could reproduce it.
- • Sourced: you can say where it came from and why that source is trustworthy.
- • Stop. Investigate the source: who made this and why?
- • Find better coverage: what do other reputable sources say?
- • Trace claims and quotes back to the original.
Find two pieces of evidence for a claim in this unit, one from your lab/class data and one from a reputable source. Note why each source can be trusted.
- 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 — you open it through Schoology.
Minute-by-minute · 80-minute block
💡 Big idea: How does reading the order of DNA bases let scientists identify an organism they have never seen before?
- 0-10 minActivate prior knowledge: write four bases, base-pairing rules, and double-helix structure from memory
- 10-25 minRead the sequencing overview; summarize the process in two sentences in your notebook
- 25-40 minExplain in writing why two organisms have different sequences; connect to mutation and evolution
- 40-55 minExamine a sample nucleotide read; confirm it uses only A, T, C, G and has no obvious errors
- 55-70 minPredict why a unique sequence identifies an unknown pathogen; compare with a partner
- 70-80 minWrite one open question about BLAST and post it for tomorrow's lab context
- • When a new outbreak begins and no one knows the pathogen, the fastest tool available is DNA sequencing.
- • Scientists sequenced the COVID-19 virus genome in days; that sequence let researchers design tests and vaccines within weeks.
- • Today you build the conceptual foundation for Wednesday's BLAST computer lab.
- • Exit goal: a two-sentence summary of how sequencing works plus one open question to bring to the computer lab.
- 1Write what you already know about DNA's four bases and how they pair.
- 2Read the short overview of how sequencing reads base order, then summarize it in two sentences.
- 3Explain in writing why two organisms have different DNA sequences.
- 4Look at a sample read and confirm it uses only A, T, C, and G.
- 5Predict why a unique sequence could identify an unknown pathogen.
- 6Write one question you have about turning a sequence into an identification.
- • You will be able to explain what DNA sequencing measures.
- • You will be able to describe why a sequence can identify an organism.
- • You will be able to recognize a valid nucleotide read.
- • DNA is made of four nucleotide bases: adenine (A), thymine (T), cytosine (C), and guanine (G); sequencing reads their exact order.
- • Organisms differ in their DNA sequence, so comparing a read from an unknown sample to a database can identify the species.
- • Molecular identification is faster and more precise than traditional culture-based methods for many pathogens.
Your PLTW work today
DNA identification, sequencing, BLAST, controls, query coverage, and E-value. · DNA sequencing basics
Day 1 of this lesson. Open this exact section in myPLTW (reached through Schoology), then do the work below.
Do this: Open Activity 1.1.3 Using DNA to Identify Pathogens in myPLTW and read the DNA sequencing background.
Write a two-sentence summary of how sequencing works and post one open BLAST question.
Activity 1.1.2 (Investigating an Outbreak) should be complete; sequencing summary due today.
Two-sentence sequencing summary in notebook.
All PLTW activities are completed inside the PLTW course environment — this page only gives direction. Submit producibles on Schoology.
Today's PLTW tracker
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 on Schoology.
Use the code Mr. Mendoza gave you, not your name. Saved on this device.
DNA identification, sequencing, BLAST, controls, query coverage, and E-value. · DNA sequencing basics
Open Activity 1.1.3 Using DNA to Identify Pathogens in myPLTW and read the DNA sequencing background.
Activity 1.1.2 (Investigating an Outbreak) should be complete; sequencing summary due today.
This is how Mr. Mendoza sees the class keeping pace with PLTW. Be honest, it only helps if it is accurate.
🎯 Explain how DNA sequencing reads the order of bases and why that sequence can act as a fingerprint for an organism.
- Write what you already know about DNA's four bases and how they pair.
- Read the short overview of how sequencing reads base order, then summarize it in two sentences.
- Explain in writing why two organisms have different DNA sequences.
- Look at a sample read and confirm it uses only A, T, C, and G.
- Predict why a unique sequence could identify an unknown pathogen.
- Write one question you have about turning a sequence into an identification.
Vocabulary task: Notebook entry: four DNA bases with pairing rules, two-sentence sequencing summary, and one question for the BLAST lab.
Submit on SchoologyUpload by 11:29 PM for full credit.
| Task | Who |
|---|---|
| Write what you already know about DNA's four bases and how they pair. | _______ |
| Read the short overview of how sequencing reads base order, then summarize it in two sentences. | _______ |
| Explain in writing why two organisms have different DNA sequences. | _______ |
| Look at a sample read and confirm it uses only A, T, C, and G. | _______ |
| Predict why a unique sequence could identify an unknown pathogen. | _______ |
| Write one question you have about turning a sequence into an identification. | _______ |
Working solo? Put your own name in "Who" for every row.
- You will be able to explain what DNA sequencing measures.
- You will be able to describe why a sequence can identify an organism.
- You will be able to recognize a valid nucleotide read.
Teacher-posted resources
Classroom documents for this lesson. Ones marked “Open the file” open right here; the rest are posted in Schoology. Use the label on each card to choose the right move.
Open this when the class reaches this activity and use it to complete the required lesson artifact.
Placement rationale
Matched Pathogen identification, PCR, sequencing, BLAST by path:Medical-Interventions/Unit-1_How-to-Fight-Infection/1.1_The-Mystery-Infection; keywords:blast, sequencing, pathogen, dna, identification. Score 162. 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 Pathogen identification, PCR, sequencing, BLAST by path:Medical-Interventions/Unit-1_How-to-Fight-Infection/00_Unit-Overview; keywords:blast, pathogen, dna, identification. Score 150. 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 Pathogen identification, PCR, sequencing, BLAST by path:Medical-Interventions/Unit-1_How-to-Fight-Infection/00_Unit-Overview; keywords:blast, pcr, pathogen, identification. Score 150. Visibility: student-schoology (student-facing resource; link through Schoology rather than local path).
How to get there: open the CMSD website, click Clever, sign in with your Microsoft (district) account, then open Schoology from Clever.
Lab & supplies
This unit's vocabulary
Tap the speaker to hear a term. Weekly vocabulary task: add two of these terms to your notebook glossary with a definition and an example in your own words.
WebXam practice
Cumulative WebXam review
A quick mixed-review pulling questions from earlier units plus today, so the WebXam material stays fresh.
Where this leads — careers
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.
What to do if you were absent
Today is individual PLTW work, so do exactly what we did in class, from home: complete the same PLTW target above, then submit your Vocabulary task.
Open Schoology (CMSD) and keep goingHow to get there: open the CMSD website, click Clever, sign in with your Microsoft (district) account, then open Schoology from Clever.
Class still runs. Complete the online activity above (it's self-guided). Need the concept taught without a teacher? Use this authoritative explainer:
NCBI BLAST- 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 (Schoology for routine work) and confirmed.
Drop your Mon, Feb 1, 2027 · DNA sequencing basics here. Use a clear file name (your initials + project). Routine work still goes to Schoology (via the CMSD portal).
Upload a project