SDS-PAGE gel results
Open your materials, follow the steps, then turn in your work.
Read an SDS-PAGE gel to judge the size and purity of your isolated protein.
1. Open your materials
Use the materials named in the first step below. Open lesson resources.
2. Start the work
Read the gel-interpretation notes in the PLTW course shell and define the protein marker lane.
Show all 5 required steps
- Read the gel-interpretation notes in the PLTW course shell and define the protein marker lane.
- Compare your fraction lanes to the marker to estimate your protein's size.
- Decide which fraction is most pure based on how few extra bands it shows.
- Write one QC statement on whether the purification met the purity goal.
- Add your annotated gel reading to your Unit 4 PLTW tracker evidence.
Lost your place? Reopen today's SDS-PAGE gel results record. Find the last completed evidence ID, check it against the claim ceiling, and continue with the first unfinished step rather than restarting the whole task.
Check your work before submitting
- You'll be able to estimate protein size against a marker lane.
- You'll be able to judge purity and write a QC statement from a gel.
Before lab work: read the safety rules
- No new chemical hazards today; gel image analysis is a paper or digital exercise.
- If handling a physical stained gel, wear gloves as Coomassie stain is a skin irritant.
- Dispose of any staining waste according to lab guidelines.
3. Turn in your work
DueCheck Schoology- Hand in
- Annotated SDS-PAGE gel image with labeled marker lane, estimated protein size, band counts by fraction, most-pure fraction identified, and a QC statement.
How to submit and name your file
Use the submission route shown on today's 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.
PDF upload helpYou get two school days for every day you were absent, so this deadline moves with you.
Find this lesson's Schoology assignments
These are existing assignments for your section. Follow the directions in the assignment you are working on; this list does not add new work. Check Schoology for each deadline.
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How this lesson connects
Keep using what you learned last class: Molecular workflows use controls and complementary separation or detection steps to evaluate a target, while each band, fraction, or colony remains limited by method resolution and sample quality. Today: Molecular workflows use controls and complementary separation or detection steps to evaluate a target, while each band, fraction, or colony remains limited by method resolution and sample quality.
Optional: listen or watch a unit review▸
Need help? Warm-up, timing, and directions▸
💡 Big idea: Molecular workflows use controls and complementary separation or detection steps to evaluate a target, while each band, fraction, or remains limited by method resolution and sample quality.
- 0-10Read gel-interpretation notes; define marker lane and band
- 10-28Annotate gel image: label marker lane, estimate target size
- 28-45Compare fraction lanes; count extra bands per lane
- 45-58Identify most-pure fraction; justify with band count
- 58-70Write QC statement: passed or failed goal with evidence
- 70-80Add annotated gel to tracker; preview Friday lab report
- • You collected fractions yesterday; today you find out what is actually in them.
- • SDS-PAGE separates proteins by size and makes every contaminant visible as a band.
- • A clean gel with one band says your worked; extra bands say it did not.
- • Gel interpretation is a core Lab SOPs skill tested on the 072130 WebXam.
- • SDS denatures proteins and gives all of them a uniform negative charge proportional to size.
- • Smaller proteins migrate farther through the gel matrix in a given time.
- • A pure target fraction shows one dominant band at the expected molecular weight.
PLTW connection and today's work
Open Activity 4.1.3 Protein Purification in myPLTW and interpret your SDS-PAGE gel to judge the size and purity of the isolated protein.
Today's stopping point: Fraction-collection data should be done (Wednesday); annotated gel and QC statement 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.
Course connection
- Activity 4.1.3 Protein Purification
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.
Molecular workflows use controls and complementary separation or detection steps to evaluate a target, while each band, fraction, or remains limited by method resolution and sample quality.
Molecular workflows use controls and complementary separation or detection steps to evaluate a target, while each band, fraction, or remains limited by method resolution and sample quality.
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: Your fractions glowed green yesterday, but did you actually purify the target, or did contaminants ride along? What do the bands on your SDS-PAGE gel say?
What you already know: Molecular workflows use controls and complementary separation or detection steps to evaluate a target, while each band, fraction, or remains limited by method resolution and sample quality.
New idea: Molecular workflows use controls and complementary separation or detection steps to evaluate a target, while each band, fraction, or remains limited by method resolution and sample quality.
Visual or model: F1. F1. A lesson illustration or teaching diagram for SDS-PAGE gel results. 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 SDS-PAGE gel results.
- 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: Today the medical interventions team uses SDS-PAGE gel results to make a bounded evidence decision. A band, selected , or fluorescent fraction alone does not prove identity, , correct sequence, biological activity, or clinical suitability.
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.
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.
National Center for Biotechnology Information is the source this lesson's claim is checked against:
Limit: A band, selected , or fluorescent fraction alone does not prove identity, , correct sequence, biological activity, or clinical suitability.
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.
You can estimate size against a marker lane.
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-2026-12-11 · Simulated classroom evidence scenario
Your role: medical interventions team member
Decision: Your team must decide what the evidence from SDS-PAGE gel results supports before submitting the labeled and result claim named on today's page.
- • Turn in a clean, well organized report, since strong presentation shows the results are trustworthy on their own.
- • Add an activity test before claiming the works, because a band shows size and , not biological function.
- • Write the report so each result names its control and states what the gel cannot prove about your .
Response: State one choice, cite at least two evidence IDs, explain the rule that connects them, and add one limitation. Submit it as the labeled and result claim.
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.
Reason for review: Your team must decide what the evidence from SDS-PAGE gel results supports before submitting the labeled and result claim named on today's page.
Context: Today the medical interventions team uses SDS-PAGE gel results to make a bounded evidence decision. A band, selected , or fluorescent fraction alone does not prove identity, , correct sequence, biological activity, or clinical suitability.
- • T1: Read the gel-interpretation notes in the PLTW course shell and define the lane.
- • T2: Compare your fraction lanes to the marker to estimate your 's size.
- • T3: Decide which fraction is most pure based on how few extra bands it shows.
- • T4: Write one QC statement on whether the met the goal.
- • T5: Add your annotated gel reading to your Unit 4 PLTW tracker evidence.
- • E1: National Center for Biotechnology Information is the source this lesson's claim is checked against:
- • E2: Define variables, controls, sampling, units, and the analysis plan before interpreting a result; analysis cannot repair biased or inconsistent measurement.
- • E3: You can estimate size against a marker lane.
Measurements: Use only the measurements, units, graph, or counts supplied in today's task. No additional patient measurement is implied.
Figure finding: Teaching diagram for SDS-PAGE gel results. Trace the labeled testing, treatment, or biological process and identify where evidence limits the decision. 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.
Rate or percent = part / comparison total x 100%. Percent change = (new - comparison) / comparison x 100%.
If 18 of 60 records meet a condition, the frequency is 18 / 60 x 100% = 30%.
Name the comparison total. A percent describes the supplied group and does not automatically predict an individual's outcome.
Use today's supplied counts to calculate one rate, risk, frequency, or percent change. Show the denominator and interpretation.
Students often think A polished answer about SDS-PAGE gel results is trustworthy even when its evidence source, comparison, or limitation is missing.. The trap: Presentation quality cannot raise the evidence level. A band, selected , or fluorescent fraction alone does not prove identity, , correct sequence, biological activity, or clinical suitability.
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.
- 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.
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 and quality control by path:Medical-Interventions/Unit-4_When-Organs-Fail/4.1_Manufacturing-Human-Proteins; keywords:protein purification, gfp, . Score 150. Visibility: student-schoology (student-facing resource; link through Schoology rather than local path).
Open this when the class reaches this activity and use it to complete the required lesson artifact.
Placement rationale
Matched and quality control by path:Medical-Interventions/Unit-4_When-Organs-Fail/4.1_Manufacturing-Human-Proteins; keywords:protein purification, gfp, . 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 and quality control by path:Medical-Interventions/Unit-4_When-Organs-Fail/4.1_Manufacturing-Human-Proteins; keywords:gfp, . Score 142. 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 SDS-PAGE gel results. It cannot prove causation, diagnose a real patient, or justify action outside this room.
A student makes a certain conclusion about SDS-PAGE gel results from one classroom result. What must the student add before the conclusion is defensible?
Write an answer and pick a confidence to unlock the key.
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.
I can name the procedure's purpose and the evidence I will record. I can name today's hazards and the control for each: If handling a physical stained gel, wear gloves as Coomassie stain is a skin irritant. My data table is ready before materials are handled.
Finish the checklist before you handle any material.
- • No new chemical hazards today; gel image analysis is a paper or digital exercise.
- • If handling a physical stained gel, wear gloves as Coomassie stain is a skin irritant.
- • Dispose of any staining waste according to lab guidelines.
- 1Before materials are handled, identify the purpose, variables or comparison, controls, measurement units, and stop-work condition.
- 2Read the gel-interpretation notes in the PLTW course shell and define the protein marker lane.
- 3Compare your fraction lanes to the marker to estimate your protein's size.
- 4Decide which fraction is most pure based on how few extra bands it shows.
- 5Write one QC statement on whether the purification met the purity goal.
- 6Add your annotated gel reading to your Unit 4 PLTW tracker evidence.
- 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.
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 Data table 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: Genetics basics and proteinsYou'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.
- 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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