--- title: "Polymerase chain reaction (PCR) Template | MolDraw" url: https://www.moldraw.com/templates/biopath-pcr/ description: "Polymerase chain reaction (PCR) template: Denaturation (≈ 95 °C), annealing (≈ 55–65 °C) and extension (72 °C) with Taq polymerase, the temperature profile…" lang: en publisher: Scidart Academy generated: 2026-10-28 --- [MolDraw](https://www.moldraw.com/) › [Templates](https://www.moldraw.com/templates/) › [Biochemistry](https://www.moldraw.com/templates/biochemistry/) › Polymerase chain reaction (PCR) [Biochemistry](https://www.moldraw.com/templates/biochemistry/)Premium # Polymerase chain reaction (PCR) template ![Polymerase chain reaction (PCR) template: Denaturation (≈ 95 °C), annealing (≈ 55–65 °C) and extension (72 °C) with Taq polymerase, the temperature profile, exponential growth 2ⁿ and the phosphodiester bond made from a dNTP.](https://www.moldraw.com/templates/biopath-pcr.webp) [Edit in MolDraw](https://www.moldraw.com/)Download with Pro Premium template. Preview and edit it free in MolDraw; downloading and exporting it is part of [MolDraw Pro](https://www.moldraw.com/pricing). Denaturation (≈ 95 °C), annealing (≈ 55–65 °C) and extension (72 °C) with Taq polymerase, the temperature profile, exponential growth 2ⁿ and the phosphodiester bond made from a dNTP. ## What the template shows - Heat to separate, cool to anneal primers, extend with a heat-stable polymerase: the target doubles every cycle - One cycle - H-bonds between the strands break - Primers pair with the 3′ end of each strand - Taq polymerase adds dNTPs 5′ → 3′ - repeat 25–35 cycles: each cycle doubles the target - template strand - complementary strand - Exponential amplification - time (two cycles) - cycle n → copies 2ⁿ - After n cycles: - copies = 2ⁿ × start - Extension chemistry - The primer’s 3′-OH attacks the α-phosphate of the incoming dNTP; R = primer strand, R′ = deoxynucleoside (5′-CH₂ shown) - After n cycles there are up to 2ⁿ copies per starting duplex; the exact-length product appears from cycle 3 (2ⁿ − 2n copies). - Primers (≈ 18–25 nt) set both ends of the product; annealing is run a few °C below their melting temperature. - Taq DNA polymerase (Thermus aquaticus) survives 95 °C, so it is added once; it extends only from a 3′-OH, 5′ → 3′. - The reaction plateaus after 25–35 cycles as primers and dNTPs are used up and the polymerase tires. Drawn with 34 atoms, 1 arrow, 153 shapes – every one editable in MolDraw. ## Sources - [Nelson & Cox, Lehninger Principles of Biochemistry, 8th ed., 2021](https://openlibrary.org/isbn/9781319228002) Textbook - [Berg, Tymoczko, Gatto & Stryer, Biochemistry, 9th ed., 2019](https://openlibrary.org/isbn/9781319114657) Textbook - [Saiki et al., Science 1988, 239, 487](https://doi.org/10.1126/science.2448875) Original paper ## How to use this template 1. Press **Edit in MolDraw**. The template opens on the canvas of the free MolDraw editor. 2. Change anything: move structures, edit atoms and labels, recolour highlights or delete what you do not need. 3. Add your own structures, arrows and text next to it, or combine several templates on one page. 4. Export the drawing as PNG, SVG or PDF for slides, worksheets, theses and papers. ## Frequently asked questions ### Is the Polymerase chain reaction (PCR) template free? You can preview the Polymerase chain reaction (PCR) template here and open and edit it in MolDraw for free. Downloading or exporting it is part of MolDraw Pro, together with the other premium templates. ### Can I edit the Polymerase chain reaction (PCR) template? Yes. It opens as an ordinary MolDraw drawing, so every structure, arrow, label and colour can be changed, and you can add your own content around it. ### Is the chemistry checked? Every structure is checked with RDKit and every curly arrow passes MolDraw’s electron-flow audit. The sources used are listed on this page. ### Are the biochemical pathways drawn with structures? Yes. 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