Protein-purification lab

Open your materials, follow the steps, then turn in your work.

Run a protein-purification procedure and collect fractions to isolate the target protein.

Before lab work: Read the safety rules below and wait for your teacher’s approval. You may read the directions while you wait.

1. Open your materials

Use the materials named in the first step below. Open lesson resources.

2. Start the work

Read the lab protocol in the PLTW course shell and set up your column and tubes.

Show all 6 required steps
  1. Read the lab protocol in the PLTW course shell and set up your column and tubes.
  2. Load the protein mixture and begin collecting numbered fractions.
  3. Add buffer to elute the bound protein and watch for the GFP signal under UV.
  4. Record which fractions glow and label them as your target collection.
  5. Note one source of error and how you controlled for it.
  6. Submit your fraction-collection data sheet.

Lost your place? Reopen today's Protein-purification lab 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 run a column purification and collect fractions.
  • You'll be able to identify target fractions using the GFP signal.

Before lab work: read the safety rules

  • Wear nitrile gloves and safety goggles throughout the procedure.
  • UV light is harmful to eyes and skin; never look directly into the UV lamp and minimize exposure to skin.
  • Treat all protein samples as potential allergens; avoid contact with eyes and mouth.
  • Dispose of all biological waste in designated containers per lab protocol.
  • Wipe the bench with 70% ethanol before and after the procedure.
  • Report any spill or broken glassware to the teacher immediately.

3. Turn in your work

DueCheck Schoology
Hand in
Fraction-collection data sheet recording tube number, buffer applied, GFP signal (yes/no), and target-fraction labels plus one error-control note.
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 help

You 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.

Link will not open? Open Schoology, choose your course and section, and find the title shown above.

How this lesson connects

Keep using what you learned last class: A planned study connects its question to defined variables, controls, sampling, measurement, and analysis so the resulting data can support a bounded and reproducible conclusion. 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
Optional unit study notebook
Purifying proteins: chromatography, SDS-PAGE, and separating a protein of interest.
Open the notebook
Optional review video
Audio overviewVideo overviewMind mapStudy guideFlashcardsQuizData table
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.

  1. 0-10Read protocol; set up column and label collection tubes
  2. 10-25Load mixture; begin collecting fractions as wash proceeds
  3. 25-45Add buffer; collect elution fractions in order
  4. 45-58Check fractions under UV; record which fractions glow
  5. 58-70Label target fractions; note source of error and control
  6. 70-80Clean up column and bench; submit fraction-collection data sheet
Mr. Mendoza's 5-minute intro
  • Today is the - lab.
  • You will run a column, collect numbered fractions, and use UV light to find your .
  • Work precisely: fraction order matters, and mislabeling a tube loses data you cannot recover.
  • Fraction data collected today feeds directly into Thursday's gel interpretation.
Know by the end
  • Loading the lysate applies all proteins to the resin; only the target binds with high affinity.
  • Wash steps remove loosely bound contaminants before begins.
  • GFP fluorescence under UV is the qualitative signal that confirms the target is in a fraction.

PLTW connection and today's work

Open Activity 4.1.3 GFP Protein Purification in myPLTW and run the protein-purification lab protocol to collect and identify your target fractions.

Today's stopping point: Chromatography diagram should be done (Tuesday); fraction-collection data sheet 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
Open Activity 4.1.3 Protein Purification in myPLTW

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

Run the lab
Complete the assigned Fraction-collection data sheet recording tube number, buffer applied, GFP signal (yes/no), and target-fraction labels plus one error-control note., cite at least two evidence IDs, apply the reviewed rule, and name one limitation.
Missed class? Start here
Use the sentence frame: E1 shows ____. E2 helps explain ____. Therefore I can claim ____, but I cannot claim ____.

Finish the assigned lab safely before starting extra practice.

Lesson resources: reading, slides, and vocabulary
Socratic teaching slide deck

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.

Carry forward

A planned study connects its question to defined variables, controls, sampling, measurement, and analysis so the resulting data can support a bounded and reproducible conclusion.

Daily take-home

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.

Inspect the analogy

A research team lays out its question, variables, controls, sampling plan, measurement record, and analysis before deciding what the data support.

  1. Which variable is changed or compared?
  2. Which conditions and measurements must stay consistent?
  3. Which conclusion is inside the study's evidence boundary?
Rule

Define variables, controls, sampling, units, and the analysis plan before interpreting a result; analysis cannot repair biased or inconsistent measurement.

Where it breaks

A well-organized classroom study can still be limited by , measurement quality, confounding, and the population represented.

Map the analogy to biology
  • 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.
Read this first

Driving question: When you actually run the column today, which of your numbered fractions will hold the target , and can you prove it with the green glow under UV?

What you already know: A planned study connects its question to defined variables, controls, sampling, measurement, and analysis so the resulting data can support a bounded and reproducible conclusion.

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 Protein-purification lab. 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.

  1. Observe or measure the relevant feature in - lab.
  2. Organize the observation with a stable evidence ID.
  3. Apply this rule: Define variables, controls, sampling, units, and the analysis plan before interpreting a result; analysis cannot repair biased or inconsistent measurement.
  4. Choose the option the evidence supports and state the limit of the conclusion.

Real biomedical example: Today the medical interventions team uses - lab 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.

Evidence set and decision
E1 · Source fact

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.

E2 · Teaching model

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.

E3 · Task criterion

You can run a column and collect fractions.

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-2026-12-10 · Simulated classroom evidence scenario

Your role: medical interventions team member

Decision: Your team must decide what the evidence from - lab supports before submitting the labeled and result claim named on today's page.

  • Read the gel by size alone, since SDS erases charge and shape and smaller proteins migrate farther down the lane.
  • Sort the bands by natural charge and shape, because the most charged should travel fastest through the gel.
  • Load a sample from before next to yours, because one lane cannot show how many contaminants you removed.

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 - lab. It cannot prove causation, diagnose a real patient, or justify action outside this room.

Composite case file · PLTW-GEND-2026-12-10

Reason for review: Your team must decide what the evidence from - lab supports before submitting the labeled and result claim named on today's page.

Context: Today the medical interventions team uses - lab to make a bounded evidence decision. A band, selected , or fluorescent fraction alone does not prove identity, , correct sequence, biological activity, or clinical suitability.

Timeline:
  • T1: Read the lab protocol in the PLTW course shell and set up your column and tubes.
  • T2: Load the mixture and begin collecting numbered fractions.
  • T3: Add buffer to elute the bound and watch for the GFP signal under UV.
  • T4: Record which fractions glow and label them as your target collection.
  • T5: Note one source of error and how you controlled for it.
  • T6: Submit your fraction-collection data sheet.
Evidence records:
  • 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 run a column and collect fractions.

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 - lab. 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.

Math moment
Formula or setup

Graph the on x and the measured on y. Slope = change in y / change in x.

Worked parallel example

A measured value rises from 4 to 10 while x rises from 1 to 3. Slope = (10 - 4) / (3 - 1) = 3 y-units per x-unit.

Units and reasonableness

Label both axes and units. Describe the visible trend before proposing a cause.

Try it with today's data

Use today's supplied data to make or interpret the graph, calculate a change when requested, and state one evidence limit.

Watch the trap

Students often think A polished answer about - lab 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.

Worked example · a parallel case (guides, does not reveal)
Fraction-collection data sheet
Completes: Completes the purification lab: a fraction-collection data sheet recording tube number, buffer applied, GFP signal, and target-fraction labels, plus one error-control note.

I loaded the protein mixture, washed, then eluted while watching for the green GFP signal under UV. Here is my record.

Reading: tubes 1 and 2 were the flow-through and wash, with no glow, meaning contaminants washed off. Tubes 4 and 5 glowed green, so those are my target collection.

Error-control note: one source of error is room light washing out the faint UV glow, so I controlled for it by reading each tube in the same darkened spot with the same UV lamp distance, so my yes/no calls are consistent.

TubeBuffer appliedGFP signalLabel
1Load flow-throughNoDiscard
2WashNoDiscard
4ElutionYesTarget
5ElutionYesTarget
Fraction data sheet: load and wash tubes show no GFP signal; elution tubes 4 and 5 glow and are labeled target.
Why this matters

This model shows the level of evidence and organization needed to complete: Completes the purification lab: a fraction-collection data sheet recording tube number, buffer applied, GFP signal, and target-fraction labels, plus one error-control note.

Build yours step by step
  1. Name the variables and include units.
  2. Enter observations without changing the raw values.
  3. Check labels, calculations, and patterns before interpreting the data.
Change it for a new task

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 fraction-collection data sheet to Schoology before leaving lab.

See the full worked example
Portal terms
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.
Teacher-posted resources

Classroom documents for this lesson are posted in Schoology. Open Clever, then Schoology, and find each one by the name shown on its card.

Use during lessonFor: Everyone
Activity 4.1.3 Protein Purification (Chromatography)
worksheet/handoutPosted in Schoology
Open in Schoology

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 during lessonFor: Everyone
4.1.3 Protein Purification by Column Chromatography Student Guide
worksheet/handoutPosted in Schoology
Open in Schoology

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).

Catch-up / reteachFor: Need extra support
GFP Purification Bio-Rad Quick Guide
worksheet/handoutPosted in Schoology
Open in Schoology

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 - lab. It cannot prove causation, diagnose a real patient, or justify action outside this room.

Quick self-check · commit, then reveal

A student makes a certain conclusion about Protein-purification lab from one classroom result. What must the student add before the conclusion is defensible?

How sure are you?

Write an answer and pick a confidence to unlock the key.

Missed class or ready for more?
🔬 Pre-lab simulation

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.

Glow and Purify: Protein Purification
Open the simulation →
Lab · prepare, conduct, complete
1Prepare
Pre-lab pass · clear all six to go to the bench
0/6

I can name the procedure's purpose and the evidence I will record. I can state today's specific hazards and the control for each. If this deck does not name them, I ask Mr. Mendoza before I touch anything. My data table is ready before materials are handled.

Finish the checklist before you handle any material.

Bring / set up
Affinity chromatography column (pre-packed resin per PLTW kit or equivalent)Cell lysate containing GFP-tagged recombinant proteinWash buffer (appropriate for resin type)Elution bufferNumbered microcentrifuge collection tubes (1.5 mL, at least 8)Micropipettes and sterile tips (100 uL, 1000 uL)UV lamp or handheld UV light source (365 nm)Tube rackPermanent marker for labelingLab notebook or fraction-collection data-sheet printoutWaste collection beaker
Safety · specific to today's hazards
  • Wear nitrile gloves and safety goggles throughout the procedure.
  • UV light is harmful to eyes and skin; never look directly into the UV lamp and minimize exposure to skin.
  • Treat all protein samples as potential allergens; avoid contact with eyes and mouth.
  • Dispose of all biological waste in designated containers per lab protocol.
  • Wipe the bench with 70% ethanol before and after the procedure.
  • Report any spill or broken glassware to the teacher immediately.
Review Lab Safety (rules, PPE, SDS, emergencies) and check your contract + test
2Conduct (Argument-Driven Inquiry)
  1. 1Before materials are handled, identify the purpose, variables or comparison, controls, measurement units, and stop-work condition.
  2. 2Read the lab protocol in the PLTW course shell and set up your column and tubes.
  3. 3Load the protein mixture and begin collecting numbered fractions.
  4. 4Add buffer to elute the bound protein and watch for the GFP signal under UV.
  5. 5Record which fractions glow and label them as your target collection.
  6. 6Note one source of error and how you controlled for it.
  7. 7Submit your fraction-collection data sheet.
  8. 8Record each result in the prepared table before interpreting it. Mark missing, repeated, or invalid results truthfully.
  9. 9Complete the named cleanup and waste route, remove PPE safely, wash hands when required, and confirm the station is ready for the next group.
Prepare this data table before materials are handled
Trial or sample IDIndependent conditionMeasured result with unitsObservation before interpretationQuality-control note
     
     
     
Genetic Science Learning Center: Genetics basics and proteins
3Complete
Argue from your evidence, then compare what you predicted to what happened. Error analysis names a specific method limit, never "human error".
You predicted

Before the procedure, predict the result and cite the rule behind the prediction.

What actually happened

After the procedure, compare the result with the prediction and name one limitation or source of uncertainty.

Your lab report is graded on the rubric below, with extra weight on error analysis and method.
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 was a lab: do this instead

Complete the virtual - run linked on the class site, recording which fractions show the GFP signal under UV, then submit your fraction-collection data sheet.

Learn.Genetics: Gel Electrophoresis

Use the submission route shown on today's today's page.

If MR. MENDOZA is absent

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 proteins
Optional extra credit (async)

You'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
How this is graded
For: Data table: Fraction-collection data sheet recording tube number, buffer applied, GFP signal (yes/no), and target-fraction labels plus one error-control note.
  • Complete
    Every required part of the artifact is present, nothing left blank.
  • Accurate
    The science and the data are correct and match the evidence.
  • Scientific reasoning
    You explain your claim with evidence and reasoning (CER), not just an answer.
  • Professional communication
    Clear, organized, labeled, and written the way a clinician or scientist would.
  • Submitted
    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. If you cannot get in, see Mr. Mendoza. Do not skip the work.
  • Error analysis and method · counts double
    Name 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.