Question

Other than DNA polymerase, which are the enzymes involved in DNA synthesis?

• A. Topoisomerase
• B. Helicase
• C. RNA primase
• D. All of the above

Answer 1

Answer: (D)

Topoisomerase, helicase and RNA primase enzymes are involved in DNA synthesis. They perform following functions :
(i) Topoisomerase reduces the tension, which is produced due to unwinding of DNA strands.
(ii) Helicase or unwindase is the enzyme, which separates $2$ strands of DNA at the site of origin of replication or ori. The separated strands are stabilised by Single Strand Binding Proteins (SSBPs).
(iii) RNA primase or RNA polymerase enzyme: A small strand of RNA $(4-12$ nucleotides) called primer is synthesized at the $3^{\prime }$ end of each template with the help of this enzyme. RNA primers function as $5^{\prime }$ ends of new strands. The primer lies at the free end of the template strand and fork end of other template strand.