How many steps are there in one $PCR$ cycle?

Discuss briefly how a probe is used in molecular diagnostics.

How many basic steps are involved in the creation of a $GMO$?

Plasmid $pBR322$ has a $PstI$ restriction enzyme site within the gene $amp^R$ that confers ampicillin resistance. If this enzyme is used for inserting a gene for $\beta$-galactosidase production and the recombinant plasmid is inserted into an $E. coli$ strain:

Following enzymes/chemical/technique are used in the process of gel electrophoresis:
$I.$ sample $DNA$ is cut into fragments
$II.$ restriction endonucleases
$III.$ agarose gel
$IV.$ ethidium bromide
$V.$ $UV$-radiation
$VI.$ elution
Mark the correct sequence of their use.

Gel electrophoresis is used for: