DNA sequencing basics
Fri, Sep 11, 2026 · Week 3 · Genetics of Disease (Medical Interventions)
Today's goal: Explain what DNA sequencing measures, the order of bases in a sample, and what a later comparison with reference sequences adds before a read can help name an organism.
This is a model of the work you should turn in today. Use it to check your own: match the structure and the level of detail, do not copy it. Your data and wording should be your own.
Four DNA bases and pairing rules:
- Adenine (A) pairs with Thymine (T).
- Cytosine (C) pairs with Guanine (G).
What sequencing measures (two sentences): DNA sequencing reads the exact order of the A, T, C, and G bases along a strand. A read is the reported order of bases for one sample; it does not by itself say how well the strand was read.
What a comparison adds (Monday): matching the read against reference sequences can point to the organism it came from, if the read is good and a matching reference exists. The letters alone name nothing.
My question for the BLAST lab: how close does a match have to be before we can trust that two sequences are from the same species?
This model shows the level of evidence and organization needed to complete: A notebook entry listing the four DNA bases and their pairing rules, a two-sentence summary of what sequencing measures, and one question to carry into the BLAST lab.
- 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 one PDF of the entry to the September 11 Schoology assignment (Wk3 Vocabulary: DNA sequencing basics) by 11:59 PM, unless the paper entry was collected in class; bring the notebook to Monday's BLAST lab.
Submit one PDF of the entry in the September 11 Schoology assignment by 11:59 PM, unless Mr. Mendoza collected the paper entry in class; bring the notebook to Monday's BLAST lab.
Turn in: Wk3 Vocabulary: DNA sequencing basics (one PDF; skip if collected on paper)Claim ceiling: A read reports base order. The letters alone cannot show how well the strand was read, and a short illustrative read cannot name an organism; identification is a later comparison with reference data.
One exam-style question that uses exactly what you practiced today. Try it before you reveal the answer, then read why each choice is right or wrong.
Tap an answer to see the full explanation. Nothing is recorded or graded.
It builds this reusable test skill: Recognizing the DNA alphabet and base pairing.
- Name the concept or data pattern being tested.
- Cross out choices that violate that rule or the evidence.
- Justify the best remaining choice before checking the answer.