PCR Detective — iLearnSTEM Labs

iLearnSTEM Labs

labs.ilearnstem.ca — Virtual Science Laboratories

Ontario Curriculum · Grades 9–12Beta

PCR Detective700 bp target · Tm 60 °C

+ control — known S. pyogenes DNA94/55/72 °Cext 30 s×25 cycles

copies (live)0SYBR glow ∝ log copies

resultrun the cycler to measure

protocolη = 100%/cycle → ≈1.00e7-fold potential

N = 1000 × 2^n — until the reagents plateau

Ready — pick a sample, program the cycler, run.

Biochemistry Lab 04 · PCR Detective — drag to orbit, scroll to zoom

Load a sample

Six tubes, one reaction: the + control and water blank prove your protocol, the four swabs are the case. Primers flank a 700 bp locus in S. pyogenes.

Program the cycler

Denature94 °C

Anneal (primer Tm 60 °C)55 °C

Extend at 72 °C30 s

Cycles25

700 bp needs ≈ 17 s of extension. Anneal a few °C below Tm — hotter and primers don't stick, much colder and they stick to the wrong sites.

Protocol outlook

efficiency/cycle = 100% · a target would reach ≈ 1.00e7-fold

under this exact program — if the target is present. A strong number here proves nothing about a swab until you run it.

The run compresses hours to seconds — watch the tube fluoresce as copies double. Record each run: the amplification curve and the challenges feed on YOUR measurements.