Plaque assay and eye dissection
Open your materials, follow the steps, then turn in your work.
Perform an antiviral plaque assay and an eye dissection to connect structure, infection, and treatment.
1. Open your materials
Use the materials named in the first step below. Open lesson resources.
2. Start the work
Review plaque-assay setup and dissection safety.
Show all 5 required steps
- Review plaque-assay setup and dissection safety.
- Apply antiviral treatments to plated samples.
- Count and record plaque numbers per condition.
- Dissect the eye and identify major structures.
- Record observations linking structure to function.
Lost your place? Reopen today's Plaque assay and eye dissection 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
- Plaque counts are recorded for every condition.
- Eye structures are correctly identified and labeled.
Before lab work: read the safety rules
- Treat every plaque-assay plate and any viral or cell-culture sample as a biohazard. Keep lids on except when applying treatment, never pipette by mouth, and do not open a plate that shows unexpected contamination; call the teacher over instead.
- Wear nitrile gloves and splash goggles the entire block, for both the plaque assay and the eye dissection. Preserved cow or sheep eyes carry fixative residue, so avoid touching your face, and tell the teacher right away if fixative contacts your skin or eyes so you can flush at the eyewash for 15 minutes.
- Cut with the scalpel and scissors moving away from your hand and your partner, one cut at a time. Keep the probe and forceps out of the cut path, and report any nick to skin immediately; never try to catch a dropped blade.
- Dispose of all biological material (eye tissue, used plates, gloves, soaked pads) in the biohazard bag, and place scalpel blades in the sharps container only. Nothing biological or sharp goes in the regular trash.
- Label your data sheet and any sample container with your group code, not a student name. When you finish, dispose of waste in the marked biohazard and sharps containers, wipe down the tray, remove gloves last, and wash your hands with soap before leaving the lab or eating.
3. Turn in your work
DueCheck Schoology- Hand in
- Plaque-count data table with percent reduction calculated per antiviral condition, plus a labeled eye-structure diagram noting one structure vulnerable to viral infection.
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.
Choose your Schoology section. Open only one assignment.
Check the section number beside Human Anatomy and Physiology in Schoology.
Assignment: Wk16 Lab report: Plaque assay and eye dissection
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How this lesson connects
Keep using what you learned last class: A plaque assay estimates infectious virus from plaques formed under defined culture and dilution conditions, so antiviral comparisons require controls, countable dilutions, and a stated calculation rule. Today: A plaque assay estimates infectious virus under defined culture conditions, while eye dissection reveals structure; the two evidence types answer different questions and must not be treated as interchangeable.
Unit 3 guide: what to keep and use nextOptional: listen or watch a unit review▸
Need help? Warm-up, timing, and directions▸
💡 Big idea: A estimates infectious virus under defined conditions, while eye dissection reveals structure; the two evidence types answer different questions and must not be treated as interchangeable.
- 0-10 review: dissection tools, viral-sample handling, disposal
- 10-25: apply treatments and control; set up plates per protocol
- 25-42Count and record plaque numbers for each condition; calculate percent reduction
- 42-58Eye dissection: expose and identify cornea, lens, vitreous, retina, optic nerve
- 58-70Draw and label eye-structure diagram; note one structure vulnerable to viral infection
- 70-80Cleanup per protocol; submit and eye diagram
- • Plaque counting is how virologists measure how well an drug actually works.
- • You will count plaques from your and then dissect an eye to understand what viral infection can damage.
- • Both skills require careful observation and precise recording; sloppy data here produces a weak CER tomorrow.
- • Leave with a complete plaque-count and labeled eye-dissection diagram.
- • Fewer plaques in a treated condition indicates effectiveness; the control establishes the baseline plaque count.
- • The eye contains the cornea, lens, vitreous humor, retina, and optic nerve, all vulnerable to infection.
- • Linking a quantitative result (plaque count) to a structural observation (eye ) is a cross-system thinking skill.
PLTW connection and today's work
Complete any plaque-assay or eye-dissection lab check-in in Activity 3.2.3 Going Un-Viral and Project 3.2.4 More than Meets the Eye (Lesson 3.2 Body Guards) on myPLTW that accompanies today's lab activities.
Today's stopping point: Transmission task is done; today the lab check-in should show complete alongside your submitted lab notes.
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 3.2.3 Going Un-Viral
- Project 3.2.4 More than Meets the Eye
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.
A estimates infectious virus from plaques formed under defined and dilution conditions, so comparisons require controls, countable dilutions, and a stated calculation rule.
A estimates infectious virus under defined conditions, while eye dissection reveals structure; the two evidence types answer different questions and must not be treated as interchangeable.
A detective board holds observations, possible explanations, and one next question.
- Which notes are direct observations?
- Which notes are explanations?
- What new evidence would separate the explanations?
Keep observations separate from explanations, then collect the evidence that can distinguish the options.
Biomedical investigations use controlled procedures and validated measurements, not intuition alone.
- • Board notes map to the signs, results and measurements you recorded.
- • Possible explanations map to the competing biological causes.
- • The next question maps to the test or observation that would separate them.
Driving question: Perform an and an eye dissection to connect structure, infection, and treatment.
What you already know: A estimates infectious virus from plaques formed under defined and dilution conditions, so comparisons require controls, countable dilutions, and a stated calculation rule.
New idea: A estimates infectious virus under defined conditions, while eye dissection reveals structure; the two evidence types answer different questions and must not be treated as interchangeable.
Visual or model: F1. F1. A lesson illustration or teaching diagram for Plaque assay and eye dissection. Use it with E1-E3; it is a model or context image, not experimental or patient data. What to notice: Trace the labeled structure, movement, or system relationship that connects form to function.
- Observe or measure the relevant feature in today's lesson.
- Organize the observation with a stable evidence ID.
- Apply this rule: Keep observations separate from explanations, then collect the evidence that can distinguish the options.
- Choose the option the evidence supports and state the limit of the conclusion.
Real biomedical example: Today the human body systems team uses and eye dissection to make a bounded evidence decision. Plaque counts depend on cells, dilution, volume, and technique, while dissection does not establish infection or treatment effectiveness.
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.
- • : A lab method that counts infectious viruses by the clear spots they leave where they destroy cells in a layered dish.
- • : A type of medicine that fights viral infections by blocking a virus from entering cells or copying itself, rather than killing the virus outright.
- • : A microorganism such as a bacterium, virus, fungus, or parasite that can cause disease in its host.
- • : The passing of a disease-causing agent from one host to another, by routes such as contact, droplets, contaminated objects, or vectors.
- • titer: Use the lesson context and glossary entry to explain titer in your own words.
- • : Planned actions taken to reduce the chance of harm or to lessen its impact if it does happen.
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 Library of Medicine is the source this lesson's claim is checked against: Viral
Limit: Plaque counts depend on cells, dilution, volume, and technique, while dissection does not establish infection or treatment effectiveness.
Keep observations separate from explanations, then collect the evidence that can distinguish the options.
Limit: Biomedical investigations use controlled procedures and validated measurements, not intuition alone.
Plaque counts are recorded for every condition.
Limit: E3 defines the classroom product or success criterion. It is not independent scientific evidence and cannot justify a clinical or causal claim.
PLTW-HAP-2027-05-07 · Simulated classroom evidence scenario
Your role: anatomy and physiology consultant
Decision: Your team must decide what the evidence from today's lesson supports before submitting the lab report named on today's page.
- • Combine the neat dissection drawing with your plaque numbers, because a polished write-up makes the treatment claim strong.
- • Hold the comparison until an untreated plate is counted, because plaque numbers alone cannot show what the drug changed.
- • Record plaque counts for every condition and label eye structures separately, since the two results answer different questions.
Response: State one choice, cite at least two evidence IDs, explain the rule that connects them, and add one limitation. Submit it as the lab report.
Claim ceiling: Today's evidence supports a classroom claim about today's lesson. 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 today's lesson supports before submitting the lab report named on today's page.
Context: Today the human body systems team uses and eye dissection to make a bounded evidence decision. Plaque counts depend on cells, dilution, volume, and technique, while dissection does not establish infection or treatment effectiveness.
- • T1: Review plaque- setup and dissection .
- • T2: Apply treatments to plated samples.
- • T3: Count and record plaque numbers per condition.
- • T4: Dissect the eye and identify major structures.
- • T5: Record observations linking structure to function.
- • E1: National Library of Medicine is the source this lesson's claim is checked against: Viral
- • E2: Keep observations separate from explanations, then collect the evidence that can distinguish the options.
- • E3: Plaque counts are recorded for every condition.
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 and eye dissection. Trace the labeled structure, movement, or system relationship that connects form to function. 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.
= final volume / sample volume. New concentration = starting concentration / dilution factor.
Mix 1 mL of sample to a final volume of 10 mL. The is 10. A 100 mg/mL starting sample becomes 10 mg/mL.
Use the same volume units before dividing. Concentration keeps its original concentration unit.
Apply the same setup to one supplied dilution or dose. Show the factor, new value, units, and a reasonableness check.
- • The solution must address the stated need in today's lesson.
- • The decision must be supported by E1-E3.
- • The final product must make the success criteria visible.
- • Complete the work inside the 80-minute block.
- • Use only supplied or teacher-approved materials and evidence.
- • Do not trade , accessibility, or privacy for speed.
- • and evidence quality: must pass before scoring other criteria.
- • User need and effectiveness: highest scored criterion.
- • Time, cost, and ease of use: compare only after and effectiveness pass.
Test evidence: For each option, record the E1-E3 result that supports or fails each criterion. Do not assign a score without a named observation.
- Version or option tested
- Criterion met or missed
- Evidence ID and result
- Revision made
- Reason for the revision
- Need and user
- Criteria and constraints
- Chosen option and evidence
- Test result
- Revision and reason
Students often think A polished answer about and eye dissection is trustworthy even when its evidence source, comparison, or limitation is missing.. The trap: Presentation quality cannot raise the evidence level. Plaque counts depend on cells, dilution, volume, and technique, while dissection does not establish infection or treatment effectiveness.
Part 1: Antiviral plaque assay
Setup: each condition plated in 3 wells on a cell lawn; plaque counts averaged.
- No-virus control: 0, 0, 0 -> average 0 plaques (confirms the plates were not contaminated).
- Untreated virus control: 50, 46, 48 -> average 48 plaques.
- Antiviral A: 24, 20, 22 -> average 22 plaques. Percent reduction = (48 - 22) / 48 = 54%.
- Antiviral B: 10, 14, 12 -> average 12 plaques. Percent reduction = (48 - 12) / 48 = 75%.
Reading: Antiviral B cut infectious virus the most (75% fewer plaques than untreated).
Measurement-error source: plaques were counted by eye, and two plaques that overlap can be miscounted as one, which undercounts the virus.
Part 2: Eye dissection
Structures identified and labeled: cornea, iris, pupil, lens, retina, optic nerve.
Structure to function: the lens focuses light onto the retina, and the retina turns that light into signals the optic nerve carries to the brain.
Structure vulnerable to viral infection: the cornea, because it is the exposed outer surface and viruses such as herpes simplex can infect it and cloud vision.
(Tip: always run a no-virus control; the 0 count is what proves the plaques you counted came from the virus, not contamination.)
This model shows the level of evidence and organization needed to complete: Reports plaque counts for each antiviral condition with percent reduction calculated against an untreated control, then adds a labeled eye-structure diagram noting one structure that a virus can infect.
- State the question and method.
- Present the observations and data with units.
- Explain the result, limitations, and next investigation.
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 plaque-assay and eye-dissection lab report on 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.
Tap the speaker to hear a term. Add two of these to your notebook glossary with a definition and an example in your own words.
Pick just 2 or 3 words from today and make them yours: write what each one means in your own words, name the context clue or evidence that helped, then give one example from what you actually did in Plaque assay and eye dissection. Try your own words first; the glossary is there if you get stuck. This is voluntary and counts as extra credit, so keep it short.
Saved on this device. Show Mr. Mendoza or add these to your notebook glossary to claim the extra credit.
A fillable, Cornell-style notebook for Unit 3: Adventure Awaits. Type your notes, cues, and summaries right in the PDF, or print it and write by hand. Each lesson page has a cue column, a notes column, and a summary box, plus dated lab-record pages you can turn in.
HBS Unit 3 notebook: Adventure Awaits Fillable PDFCornell notes + lab recordsOpenVetted readings and references for this unit. Use them to prepare, to catch up if you were absent, or to go deeper on today's target.
Practice: try a question, then check your answer▸
Claim ceiling for this check: Today's evidence supports a classroom claim about today's lesson. It cannot prove causation, diagnose a real patient, or justify action outside this room.
A student makes a certain conclusion about Plaque assay and eye dissection 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.
Fast retrieval with instant answers, not the commit-then-reveal check above. Try each from memory first: write what you remember about the earlier units, then check yourself here.
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. This lesson has more than one, and they cover different skills.
I can name the procedure's purpose and the evidence I will record. I can name today's hazards and the control for each: Treat every plaque-assay plate and any viral or cell-culture sample as a biohazard. Keep lids on except when applying treatment, never pipette by mouth, and do not open a plate that shows unexpected contamination; call the teacher over instead. My data table is ready before materials are handled.
Finish the checklist before you handle any material.
- • Treat every plaque-assay plate and any viral or cell-culture sample as a biohazard. Keep lids on except when applying treatment, never pipette by mouth, and do not open a plate that shows unexpected contamination; call the teacher over instead.
- • Wear nitrile gloves and splash goggles the entire block, for both the plaque assay and the eye dissection. Preserved cow or sheep eyes carry fixative residue, so avoid touching your face, and tell the teacher right away if fixative contacts your skin or eyes so you can flush at the eyewash for 15 minutes.
- • Cut with the scalpel and scissors moving away from your hand and your partner, one cut at a time. Keep the probe and forceps out of the cut path, and report any nick to skin immediately; never try to catch a dropped blade.
- • Dispose of all biological material (eye tissue, used plates, gloves, soaked pads) in the biohazard bag, and place scalpel blades in the sharps container only. Nothing biological or sharp goes in the regular trash.
- • Label your data sheet and any sample container with your group code, not a student name. When you finish, dispose of waste in the marked biohazard and sharps containers, wipe down the tray, remove gloves last, and wash your hands with soap before leaving the lab or eating.
- 1Before materials are handled, identify the purpose, variables or comparison, controls, measurement units, and stop-work condition.
- 2Frame the question and the guiding claim: How much does each antiviral treatment reduce viral infectivity, and which eye structures are most exposed to a virus that enters at the front of the eye? Write down what a plaque represents (one infectious virus that killed a patch of the cell lawn) before you touch a plate.
- 3Design and run the method: plate the control and each antiviral condition from the same viral stock and dilution, count plaques per plate, then dissect the preserved eye and locate the cornea, lens, vitreous humor, retina, and optic nerve. Keep the control and dilution identical across conditions so plaque differences are caused only by the treatment.
- 4Analyze the data: for each antiviral condition calculate percent reduction as (control count minus treated count) divided by control count times 100, and back out an approximate titer from your plaque count and dilution factor. Sketch and label the dissected eye and note which structure a surface virus would reach first.
- 5Build a tentative argument (CER): make a claim naming the most effective antiviral, support it with your control-versus-treated plaque counts and percent reduction as evidence, and give reasoning that fewer plaques means fewer surviving infectious virus, so the treatment inhibited infection.
- 6Argumentation session: present your claim and plaque data to another group, and question theirs. Ask whether their control count was high enough to trust their percent reduction, whether counting error or a contaminated plate could explain a difference, and whether their titer estimate matches their dilution.
- 7Revise and report: update your claim, evidence, or reasoning based on the critique you received, name one limitation of the plaque assay (counting error, in-vitro versus in-vivo, cell-line variability), and connect your result to the eye dissection by stating which structure antiviral treatment would be protecting.
- 8Record each result in the prepared table before interpreting it. Mark missing, repeated, or invalid results truthfully.
- 9Complete 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 you count or cut, write two predictions. (1) Plaque assay: using the dilution factor written on your plates, predict roughly how many plaques the control should show and rank the antiviral conditions from most to fewest plaques you expect. State which antiviral you think will reduce plaques the most and why. (2) Eye dissection: on the blank template, predict where you will find the cornea, lens, vitreous humor, retina, and optic nerve, and mark which structure a virus entering the front surface of the eye would reach first.
During the lab, record the actual plaque count for the control and for every antiviral condition, and calculate percent reduction for each treated plate. Then draw and label the eye you actually dissected, marking each structure you located. Compare to your predictions: Was the control count near what your dilution predicted? Did the antiviral you picked actually remove the most plaques, or did another win? Which predicted structure locations were right, and which surprised you? Write one sentence explaining any gap between predicted and actual (for example a low control count, a miscount, or a structure that sat in a different place than you expected).
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.
Complete the virtual and eye dissection, recording plaque counts per treatment and labeling eye structures.
HHMI BioInteractive (preview; use assigned fallback if blocked)Use the submission route shown on today's today's page.
Class still runs. Complete the online activity above (it's self-guided). Need the concept taught without a teacher? Use this authoritative explainer:
CDC: Travelers' HealthYou'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.
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