THE MOLECULAR BASIS OF INHERITANCE
DNA REPLICATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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It ‘unzips’ the DNA Molecule
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It adds new nucleotides to the old DNA strands.
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It adds a primer made of RNA so that the DNA polymerase can attach to the strand and begin its job
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It fuses the gaps in the sugar-phosphate backbone after DNA polymerase is finished with its job.
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Detailed explanation-1: -Primase synthesizes an RNA primer to initiate synthesis by DNA polymerase, which can add nucleotides in only one direction. One strand is synthesized continuously in the direction of the replication fork; this is called the leading strand.
Detailed explanation-2: -Primase functions by synthesizing short RNA sequences that are complementary to a single-stranded piece of DNA, which serves as its template. It is critical that primers are synthesized by primase before DNA replication can occur.
Detailed explanation-3: -Primase is the ssDNA-dependent RNA polymerase that synthesizes RNA primers during DNA replication. In common with all DNA and RNA polymerases, primase has structural and functional features involved in polymer elongation. As RNA polymerase, it has structural and functional features for initiating chain synthesis.
Detailed explanation-4: -RNA primase attaches a short RNA molecule called a primer to the DNA sequence, which is removed upon the completion of DNA replication. Another enzyme involved in gene expression is called RNA polymerase, which uses template DNA strands to form RNA molecules.
Detailed explanation-5: -Primers are required because DNA polymerases, the enzymes responsible for the actual addition of nucleotides to the new DNA strand, can only add deoxyribonucleotides to the 3’-OH group of an existing chain and cannot begin synthesis de novo. Primase, on the other hand, can add ribonucleotides de novo.