SDS-PAGE gel results
Fri, Dec 11, 2026 · Week 16 · Genetics of Disease (Medical Interventions)
Today's goal: Read an SDS-PAGE gel to judge the size and purity of your isolated protein.
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.
How I read the gel: the marker (ladder) lane has bands of known molecular weights, so I use it as a ruler. Smaller proteins migrate farther down the gel, so I compare how far my band traveled to the marker to estimate size.
Reading:
- My target band lines up near the 27 kDa marker band, so I estimate the protein is about 27 kDa.
- Fraction 4 shows one strong band with almost no extra bands; fraction 2 shows several bands. So fraction 4 is the most pure.
QC statement: the purification met the purity goal, because the target fraction shows one dominant band at the expected size with very few contaminant bands, which is what a pure sample looks like.
| Lane | Bands seen | Estimated size | Note |
|---|---|---|---|
| Marker | Ladder of known sizes | reference | used as ruler |
| Fraction 2 | Several bands | mixed | impure, many contaminants |
| Fraction 4 | One dominant band | about 27 kDa | most pure, meets goal |
This model shows the level of evidence and organization needed to complete: Completes the gel-interpretation task: an annotated SDS-PAGE reading with a labeled marker lane, estimated protein size, band counts by fraction, the most-pure fraction identified, and a QC statement.
- 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: Attach your annotated gel reading to your Unit 4 PLTW tracker and submit it to Schoology.
Turn in: Annotated SDS-PAGE gel reading
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.
Open Schoology PDF upload helpIf you cannot get in, see Mr. Mendoza. Do not skip the work.
Claim ceiling: Today's evidence supports a classroom claim about SDS-PAGE gel results. It cannot prove causation, diagnose a real patient, or justify action outside this room.
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: Judging protein purity from an SDS-PAGE band pattern.
- 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.