Chapter 19: Gene Tech Flashcards
Describe the principles of polymerase chain reaction.
Goal: to produce large quantities of specific fragments of DNA from small quantities.
Begins with the rapid production of a large number of copies of a length of DNA, though only a small sample of DNA needed.
Denaturation:
DNA is separated into 2 strands, using heat at 95 celsius so hydrogen bonds between the 2 strands is broken.
Annealing:
Temperature decreased between 50 - 60 celsius so primers can be added.
Elongation:
Temperature increased to 72 celsius, as this is optimum temperature for Taq polymerase to replicate strands by complementary base pairing.
Process is repeated an dheated again to separate the strands.
Why efficient:
Taq polymerase is heat stable, and does not need replacing each cycle.
Explain why plasmids are frequently used in gene technology.
It is a small circular piece of double-stranded DNA.
They replicate independently to produce many copies.
It’s easily extracted from bacteria, and can be cut using restriction enzymes so DNA can be inserted, and can be taken up bacteria too.
Plasmids can carry market genes so helps in identifying transformed bacteria.
Plasmids can act as a vector and may carry a promoter.
