Ok, see, Taq polymerase is actually a really cool enzyme.

看，Taq聚合酶其实是一种很酷的酶。

Taq polymerase is used to amplify the cDNA through denaturation, annealing and extension steps.

Taq聚合酶通过变性、退火、延伸等步骤用于扩增cDNA。

The third step is called extension - we want to make the environment as optimal as possible for Taq polymerase to do its job.

第三步叫作延伸，我们希望尽可能使环境最优，让Taq聚合酶完成它的工作。

So not only can Taq polymerase withstand the heat during the denaturation step of PCR, but it also functions best at around 72 degrees Celsius.

因此，Taq聚合酶不仅能承受PCR变性步骤中的热量，而且在72摄氏度左右能发挥出最好的作用。

So during extension, we heat everything back up to 72 degrees, and Taq polymerase latches onto the primers, grabs some free nucleotides, and assembles the new DNA strands.

所以在延伸的过程中，我们将所有的物质加热到72度，Taq聚合酶结合在引物上抓取游离核苷酸，并组装新的DNA链。

The ingredients are the DNA that we wish to multiply, an enzyme called Taq polymerase, specific primers that bind to the DNA, and a mixture of free nucleotides - A, T, C and G.

我们想要扩增的DNA、一种叫做Taq聚合酶的酶、与DNA结合的特异性引物以及游离核苷酸A、T、C和G的混合物。

It requires a thermal cycler, filled with the DNA sample to be multiplied, thermostable Taq polymerase, primers with which we select what gets multiplied, and free nucleotides of all 4 types - A, T, C and G.

它需要往热循环仪中加入用于扩增的DNA样本、耐热的Taq聚合酶、扩增时选用的引物，以及所有4种类型的游离核苷酸A、T、C和G。