Disk diffusion and MIC lab
Run a disk-diffusion test and connect zone of inhibition to minimum inhibitory concentration.
Disk-diffusion data table: antibiotic name, zone of inhibition measurement (mm), and effectiveness ranking; plus one sentence connecting zone size to MIC.
- 1Do thisRun a disk-diffusion test and connect zone of inhibition to minimum inhibitory concentration.
- 2Use this resource
- 3Submit thisData table: Disk-diffusion data table: antibiotic name, zone of inhibition measurement (mm), and effectiveness ranking; plus one sentence connecting zone size to MIC.
- 4Submit it here
- 1CMSD website. Go to clevelandmetroschools.org and click the Clever button.
- 2Clever. Clever opens. Sign in if it asks.
- 3Microsoft (district) login. Use your district Microsoft account (the one for school).
- 4Schoology. Open Schoology, then your class, then Assignments, and find the file named below.
The file to submit is named: Genetics of Disease (Medical Interventions) › Bacterial structure, antibiotic mechanisms, MIC, resistance, and stewardship. › Data tableOpen 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 — you open it through Schoology.
Minute-by-minute · 80-minute block
💡 Big idea: How does the size of a clear zone around an antibiotic disk tell you how effective that drug is against a bacterium?
- 0-8 minDon goggles and gloves; confirm plate is labeled with the antibiotic abbreviation for each disk location
- 8-22 minUsing aseptic technique, place antibiotic disks on the bacterial lawn at the labeled positions
- 22-30 minSet plate to incubate (inverted); write in notebook what a clear zone will indicate
- 30-50 minAfter incubation (or using pre-incubated plates): measure each zone of inhibition in millimeters with a ruler
- 50-65 minRank antibiotics by zone size from largest to smallest; record in a data table
- 65-80 minDefine MIC in notebook; write one sentence connecting larger zone to lower MIC and greater effectiveness
- • The Kirby-Bauer test has been the clinical standard for antibiotic sensitivity testing since 1966 and is still used in hospitals today.
- • The data you collect today will drive your resistance and stewardship analysis on Thursday and your report on Friday.
- • Aseptic technique is critical: contamination will produce zones that mean nothing.
- • Exit goal: a data table of zone measurements in millimeters for each antibiotic disk, with an effectiveness ranking.
- 1Put on goggles and gloves and confirm your plate is labeled with each antibiotic disk.
- 2Place antibiotic disks on the bacterial lawn using aseptic technique.
- 3Set the plate to incubate and write what a clear zone around a disk will mean.
- 4Once zones form, measure each zone of inhibition in millimeters.
- 5Rank the antibiotics by zone size and relate larger zones to greater effectiveness.
- 6Define MIC and explain how a larger zone hints at a lower MIC.
- • You will be able to set up a disk-diffusion test safely.
- • You will be able to measure a zone of inhibition.
- • You will be able to relate zone size to MIC and effectiveness.
- • The Kirby-Bauer disk diffusion test measures antibiotic effectiveness by placing antibiotic-impregnated disks on a bacterial lawn and measuring the clear zone that forms.
- • The zone of inhibition is the area around the disk where bacteria could not grow; a larger zone indicates the antibiotic diffused farther and was effective at lower concentrations.
- • The minimum inhibitory concentration (MIC) is the lowest concentration of an antibiotic that prevents visible bacterial growth; a larger zone correlates with a lower MIC.
Your PLTW work today
Bacterial structure, antibiotic mechanisms, MIC, resistance, and stewardship. · Disk diffusion and MIC lab
Day 3 of this lesson. Open this exact section in myPLTW (reached through Schoology), then do the work below.
Do this: Open Activity 1.2.2 Which Antibiotic Is the Best Choice in myPLTW and apply your mechanism knowledge to the case patient.
Complete the antibiotic-selection decision guide and write your best-choice justification.
Mechanism chart should be done (Tuesday); antibiotic selection and justification due today.
Best-choice justification with mechanism reasoning in notebook.
All PLTW activities are completed inside the PLTW course environment — this page only gives direction. Submit producibles on Schoology.
Today's PLTW tracker
Check things off as you work, then submit. This tells Mr. Mendoza how you're doing so he can help the class. It does not replace turning in your producible on Schoology.
Use the code Mr. Mendoza gave you, not your name. Saved on this device.
Bacterial structure, antibiotic mechanisms, MIC, resistance, and stewardship. · Disk diffusion and MIC lab
Open Activity 1.2.2 Which Antibiotic Is the Best Choice in myPLTW and apply your mechanism knowledge to the case patient.
Mechanism chart should be done (Tuesday); antibiotic selection and justification due today.
This is how Mr. Mendoza sees the class keeping pace with PLTW. Be honest, it only helps if it is accurate.
🎯 Run a disk-diffusion test and connect zone of inhibition to minimum inhibitory concentration.
- Put on goggles and gloves and confirm your plate is labeled with each antibiotic disk.
- Place antibiotic disks on the bacterial lawn using aseptic technique.
- Set the plate to incubate and write what a clear zone around a disk will mean.
- Once zones form, measure each zone of inhibition in millimeters.
- Rank the antibiotics by zone size and relate larger zones to greater effectiveness.
- Define MIC and explain how a larger zone hints at a lower MIC.
Data table: Disk-diffusion data table: antibiotic name, zone of inhibition measurement (mm), and effectiveness ranking; plus one sentence connecting zone size to MIC.
Submit on SchoologyUpload by 11:29 PM for full credit.
| Task | Who |
|---|---|
| Put on goggles and gloves and confirm your plate is labeled with each antibiotic disk. | _______ |
| Place antibiotic disks on the bacterial lawn using aseptic technique. | _______ |
| Set the plate to incubate and write what a clear zone around a disk will mean. | _______ |
| Once zones form, measure each zone of inhibition in millimeters. | _______ |
| Rank the antibiotics by zone size and relate larger zones to greater effectiveness. | _______ |
| Define MIC and explain how a larger zone hints at a lower MIC. | _______ |
Working solo? Put your own name in "Who" for every row.
- You will be able to set up a disk-diffusion test safely.
- You will be able to measure a zone of inhibition.
- You will be able to relate zone size to MIC and effectiveness.
Teacher-posted resources
Classroom documents for this lesson. Ones marked “Open the file” open right here; the rest are posted in Schoology. Use the label on each card to choose the right move.
Open this when the class reaches this activity and use it to complete the required lesson artifact.
Placement rationale
Matched Antibiotic treatment, MIC, resistance by path:Medical-Interventions/Unit-1_How-to-Fight-Infection/1.2_Antibiotic-Treatment; keywords:antibiotic, therapy. Score 142. 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 Antibiotic treatment, MIC, resistance by path:Medical-Interventions/Unit-1_How-to-Fight-Infection/1.2_Antibiotic-Treatment; keywords:antibiotic, resistance. Score 142. 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 Antibiotic treatment, MIC, resistance by path:Medical-Interventions/Unit-1_How-to-Fight-Infection/1.2_Antibiotic-Treatment; keywords:antibiotic, resistance. Score 138. Visibility: student-schoology (student-facing resource; link through Schoology rather than local path).
How to get there: open the CMSD website, click Clever, sign in with your Microsoft (district) account, then open Schoology from Clever.
Lab & supplies
- • Goggles and gloves on before opening any bacterial culture material; keep on until cleanup is complete.
- • Treat all bacterial materials as biohazardous: no contact with skin, eyes, or mouth.
- • Open plate lids only briefly and only near the workspace; do not talk, sneeze, or cough over an open plate.
- • Incubate plates inverted (lid down) to prevent condensation dripping onto the lawn.
- • Before disposal: flood plates with 10% bleach solution and seal in a biohazard bag; autoclave if available.
- • Wash hands thoroughly with soap and water after removing gloves.
This unit's vocabulary
Tap the speaker to hear a term. Weekly vocabulary task: add two of these terms to your notebook glossary with a definition and an example in your own words.
WebXam practice
Cumulative WebXam review
A quick mixed-review pulling questions from earlier units plus today, so the WebXam material stays fresh.
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
If you miss the lab, analyze the teacher disk-diffusion plate images, measure each zone of inhibition in millimeters, and submit your ranking of antibiotic effectiveness.
CDC Antimicrobial Resistance resourcesThen submit your Data table on Schoology.
Class still runs. Complete the online activity above (it's self-guided). Need the concept taught without a teacher? Use this authoritative explainer:
CDC Antibiotic Resistance- 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.
- SubmittedTurned in the right way (Schoology for routine work) and confirmed.
Drop your Mon, Sep 28, 2026 · Disk diffusion and MIC lab here. Use a clear file name (your initials + project). Routine work still goes to Schoology (via the CMSD portal).
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