AP BIOLOGY

Detailed explanation-1: -In practice the procedure is carried out by inserting a DNA fragment into a small DNA molecule and then allowing this molecule to replicate inside a simple living cell such as a bacterium. The small replicating molecule is called a DNA vector (carrier).

Detailed explanation-2: -Researchers can insert DNA fragments or genes into a plasmid vector, creating a so-called recombinant plasmid. This plasmid can be introduced into a bacterium by way of the process called transformation. Then, because bacteria divide rapidly, they can be used as factories to copy DNA fragments in large quantities.

Detailed explanation-3: -The fragments are purified and combined. They have matching “sticky ends, ” or single-stranded DNA overhangs, so they can stick together. The enzyme DNA ligase joins the fragments with matching ends together to form a single, unbroken molecule of DNA. This produces a recombinant plasmid that contains the target gene.

Detailed explanation-4: -Preparation and insertion of recombinant DNA into the host The vector DNA and foreign DNA carrying gene of interest are cut by the same restriction enzyme. DNA ligase enzyme forms new sugar phosphate bonds to join two DNAs. The ligated DNA is introduce in the host cell.