PCR polymerase chain reaction

This is a machine to replicate a chunk of DNA

There are primers that are short strips of nucleotides constructed to bind to known sequence sections of a DNA

DNA is heated to 95C and that splits the helix into two strands. Into the soup of floating strands, primers are introduced.

Temp is reduced to 50C, allowing binding

A 3-5 primer "1" binds to the 5 end of one strand and 5-3 primer"2" binds to the 3 end of the other strand.

Nucleotides start binding to the 5 end of the primer and to the DNA, essentially recreating the strands.

After a bit they have filled in from both ends, a strand (and complement) has been replicated.

Now the new strands are separated by heating to 95C.

More primer binds and the cycle repeats.