Concentration and serial dilution
Mon, Sep 21, 2026 · Week 5 · Genetics of Disease (Medical Interventions)
Today's goal: Calculate concentrations and plan a serial dilution so you can prepare known sample strengths.
What a finished product looks like
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.
This is a parallel example on a 1:2 series, so you can see the format and then build your own plan for today's dilution.
A 1:2 dilution means one part sample to one part solvent, which makes each step half as concentrated as the step before.
Prediction: as concentration is cut in half at each step, the color or signal should get steadily weaker down the series, but more gradually than a tenfold series.
Why dilutions help: a row of known concentrations is exactly what you need to build a standard curve and read an unknown sample.
| Step | Dilution from start | Concentration |
|---|---|---|
| Start | none | 800 ng/mL |
| Step 1 | 1:2 | 400 ng/mL |
| Step 2 | 1:2 again | 200 ng/mL |
| Step 3 | 1:2 again | 100 ng/mL |
| Step 4 | 1:2 again | 50 ng/mL |
Also due today: Keep in notebook; bring to Wednesday's lab prep session.
WebXam problem for today's skill
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.