PCRAmplifying DNA, and the three temperature steps that do it.BiologyOne cycle doubles the target sequence.1Denaturation — 95°CStrands separate.2Annealing — 50–65°CPrimers bind to the flanking sequences.3Extension — 72°CTaq polymerase synthesises the new strand.4Repeat25–35 cycles. Amplification is exponential: 2ⁿ.WHY TAQFrom Thermus aquaticus, a hot-spring bacteriumSurvives 95°C without denaturingBefore it, fresh polymerase was needed every cycleqPCR measures product as it accumulates, allowing the startingquantity to be determined rather than just detected.PCRlearnposters.com
PCR — printable life science wall chart from LearnPosters. Free vector PDF, US Letter and A4.

PCR, step by step

One cycle doubles the target sequence.

  1. Denaturation — 95°CStrands separate.
  2. Annealing — 50–65°CPrimers bind to the flanking sequences.
  3. Extension — 72°CTaq polymerase synthesises the new strand.
  4. Repeat25–35 cycles. Amplification is exponential: 2ⁿ.

Why Taq

  • From Thermus aquaticus, a hot-spring bacterium
  • Survives 95°C without denaturing
  • Before it, fresh polymerase was needed every cycle

qPCR measures product as it accumulates, allowing the starting quantity to be determined rather than just detected.

Questions about the PCR poster

What’s on the PCR poster?
4 numbered steps, with a full worked run-through. One cycle doubles the target sequence. Denaturation — 95°C — Strands separate.; Annealing — 50–65°C — Primers bind to the flanking sequences.; Extension — 72°C — Taq polymerase synthesises the new strand.; Repeat — 25–35 cycles. Amplification is exponential: 2ⁿ.. qPCR measures product as it accumulates, allowing the starting quantity to be determined rather than just detected.
Who is the PCR poster for?
PCR belongs to the Biology section rather than to a school year, because life science is not something one grade owns. Anyone learning genetics can pin it up — a beginner, a student mid-course, or someone revising years later.
When should you use the PCR poster?
Denature, anneal, extend. Thirty cycles gives roughly a billion copies. A wall chart earns its place by being glanceable from where the work is happening, so PCR belongs on the wall where that life science work actually happens, within glancing distance, rather than filed away.
What other posters go with PCR?
CRISPR-Cas9, DNA Sequencing and Epigenetics sit alongside PCR in the Biology section. Printed together they make a wall rather than a single sheet, which is how a reference set actually gets used.CRISPR-Cas9DNA SequencingEpigenetics
Is the PCR poster free to download and print?
Yes. PCR downloads as a free PDF with no account, no email and no watermark, like everything else in the Biology section. Print as many copies as you like for a home, a classroom, a library or a tutoring group; reselling the file is the only thing the licence rules out.Read the licence
What size does the PCR poster print at?
PCR is a vector PDF laid out for US Letter, and prints on A4 with Fit to page — the same file, no separate download. Because every mark on it is drawn rather than photographed, it stays sharp enlarged to A3, A2 or A1 at a copy shop. Colour carries emphasis only, so a greyscale print of PCR loses nothing.Printing guide

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