$A$ : Ethidium bromide helps in visualizing $DNA$ in $UV$ light only.

$R$ : This intercalating agent absorbs light in range $260 -330 \;nm.$

Assertion : Restriction enzymes cut the strand of $DNA$ to produce sticky ends.

Reason : Stickiness of the ends facilitates the action of the enzyme $DNA$ polymerase

Which of the following statement is not correct regarding Eco $RI$ restriction endonuclease enzyme?

$I.$ Eco. $RI$ restriction endonuclease enzyme is isolated from Escherichia coli $RY13$

$II.$ Its recognition sequence is $5^{\prime}-$ $GAATTC – 3 '$

$3^{\prime}-C T T A A G-5^{\prime}$

$5^{\prime}-G-A-A-T-T-C-3^{\prime}$

$3^{\prime}-C-T-T-A-A-G-5^{\prime}$

$III.$ Its site of cleavage is

Gene for cloning may be chemically synthesized:

An enzyme catalysing the removel of nucleotides from ends of $DNA$ is