Which of the following are correctly matched?
1. Ligase - Joins short segments of DNA together
2. DNA polymerase - cuts DNA at specific site
3. Helicase breaks hydrogen bond between complementary pairs during DNA replication

Q. Match List I(Enzyme) with List II(Function) and select the correct answer using the codes given the lists.

List-I	List-II
a. DNA Ligase	$1$. Catalyses the covalent union of segments of an interrupted sugarphosphate strand in double-stranded DNA
b. DNA polymerase	$2$. End nuclease that digests either single stranded or double stranded DNA
c. DNase I	$3$. Produces single or double stranded breaks in DNA during replication to release tension brought about by the separation of double strands
d. DNA topoisomerase	$4$. Catalyses the formation of DNA worn deoxyribonucleotides using one strand of DNA as template

Q.

Match the following enzymes of DNA replication with their respective functions:
$\begin{array}{cc}p.DNApolymerase& i.HelpsunziptheDNAdoublehelix\\ q.DNAligase& ii.SealsnicksbetweenOkazakifragments\\ r.DNAhelicase& iii.LaysRNAprimerstowhichpolymerasecanaddnucleotides\\ s.Primase& iv.Addsnucleotidestothefree{3}^{\prime }endofRNAprimers\end{array}$

Q. Arrange the following steps of formation of recombinant DNA in the correct sequence.
I. Complementary sticky ends are produced on the foreign DNA and the plasmid.
II. Foreign DNA and plasmids are mixed together
III. DNA ligase is used to seal the nicks in the sugar–phosphate backbone.
IV. Cut the foreign DNA (containing the DNA fragment of interest) and the plasmid with the same restriction enzyme.

Q. How many of the following statements are correct ?

A. DNA dependent DNA polymerase requires DNA primer for initiating replication but DNA dependent RNA polymerase does not require any primer for transcription.

B. DNA dependent DNA polymerase requires RNA primer for initiating replication but DNA dependent RNA polymerase does not require any primer for transcription.

C. During replication, unwinding of DNA double helix forms a fork-like structure called replication fork.

D. During transcription, unwinding of the DNA double helix by DNA dependent RNA polymerase forms a transcription bubble.

E. During transcription, unwinding of DNA double helix by DNA dependent RNA polymerase forms a transcription fork.

Q. Match the following enzymes of DNA replication with their respective functions:
$\begin{array}{cc}\text{Column I}& \text{Column II}\\ \text{p. DNA polymerase}& \text{i. Helps unzip the DNA double helix}\\ \text{q. DNA ligase}& \text{ii. Seals nicks between Okazaki fragments}\\ \text{r. DNA helicase}& \text{iii. Lays RNA primers to which polymerase can add nucleotides}\\ \text{s. Primase}& \text{iv. Adds nucleotides to the free 3' end of RNA primers}\end{array}$