The "molecular scissors" used in genetic engineering is

While isolating $DNA$ from bacteria,which of the following enzymes is not used?

$A$ special sequence from where $DNA$ replication starts.

Which of the following would not be used in preparing recombinant $DNA$?

Given below are two statements:
Statement $I:$
Restriction endonucleases recognise specific sequences to cut $DNA$,known as palindromic nucleotide sequences.
Statement $II:$
Restriction endonucleases cut the $DNA$ strand a little away from the centre of the palindromic site.
In the light of the above statements,choose the most appropriate answer from the options given below:

What is used as a medium in gel electrophoresis?