Which enzyme polymerises okazaki fragments ?: (A) DNA polymerase I, (B) DNA polymerase II, (C) DNA polymerase III, (D) RNA polymerase
Answer is C. Ans. is 'c' i.e., DNA polymerase III Two DNA polymerases act on Okazaki fragments :? DNA polymerase :- Causes polymerization of okazaki fragments, i.e. synthesis of DNA on lagging strand. It also causes synthesis of leading strand. DNA polymerase I :- It fills the gap between okazaki fragments when their polymerization is completed, i.e. when the synthesis on lagging strand is completed, DNA polymerase I fills the gap between fully polymerized okazaki fragments. Thus, DNA polymerase III is involved during 'elongation' (polymerization of okazaki fragments) and DNA polymerase I is involved during 'termination' (filling the gaps between okazaki fragments).