SSC
BIOLOGY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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To add appropriate nucleotides in the 3’
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To remove the RNA primers and replace them with DNA
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To join together the Okazaki fragments
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To join together both strands of DNA to the histones
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Detailed explanation-1: -In prokaryotic cells, polymerase III is the major replicative polymerase, functioning in the synthesis both of the leading strand of DNA and of Okazaki fragments by the extension of RNA primers. Polymerase I then removes RNA primers and fills the gaps between Okazaki fragments.
Detailed explanation-2: -DNA polymerase I removes the RNA primer and fills in the gaps with DNA. However, DNA polymerase I cannot catalyze the reaction to remove the nicks. Another enzyme, DNA ligase, seals the nicks by forming the phosphodiester bond, thus generating a continuous sugar-phosphate backbone for the lagging strand.
Detailed explanation-3: -Because DNA polymerase can only add new nucleotides at the end of a backbone, a primer sequence, which provides this starting point, is added with complementary RNA nucleotides. This primer is removed later, and the nucleotides are replaced with DNA nucleotides.