Aseptic technique
Fri, Oct 2, 2026 · Week 6 · Genetics of Disease (Medical Interventions)
Today's goal: Practice aseptic technique so you can grow a pure culture without contaminating it or yourself.
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.
Contamination routes (how unwanted organisms get in):
- Air currents carrying dust and microbes onto an open plate
- Skin contact from touching the agar or the loop tip
- Talking, coughing, or breathing over an open plate
- Unsterilized tools, like a loop that was not flamed
Aseptic technique, in order:
1. Clean the work surface and wash your hands, then put on gloves.
2. Light the burner and work in the rising warm air near the flame.
3. Flame the inoculating loop until it glows, then let it cool a few seconds.
4. Lift the plate lid only partway and only for as long as you need.
5. Streak the sample, then close the lid right away.
6. Re-flame the loop before setting it down so nothing is carried out.
Why minimize open time: Every second a plate is open, airborne microbes can settle on the agar. Keeping it open as briefly as possible lowers the chance that anything other than my sample starts growing.
Safety rule for cultures and waste: Treat every culture as if it could be harmful. Never open an incubated plate at your seat, and dispose of plates and used tools in the marked biohazard container, never the regular trash.
Prediction: A clean plate will show only one kind of colony along my streak lines. A contaminated plate will show extra colonies of different colors or shapes, often in spots where I did not streak.
This model shows the level of evidence and organization needed to complete: Completes the pre-lab prep for the culturing lab: an ordered aseptic procedure, a contamination-routes list, an explanation of why plates stay closed, safety rules, and a prediction of clean versus contaminated growth.
- Identify the purpose, hazards, and required controls.
- Write the procedure in a usable order.
- Confirm materials, measurements, and waste handling before starting.
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: Keep this pre-lab in your notebook and bring it to the culturing lab.
Turn in: Aseptic technique pre-lab
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 aseptic technique. 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: Applying aseptic technique to prevent culture contamination.
- 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.