Question

Which of the following molecules is not required for a PCR reaction? View Available Hint(s) Ligase O Primer O DNA O DNTPs Submit Previous Answers X Incorrect; Try Again; One attempt remaining dNTPs are required because they are the building blocks of DNA molecules. - Part B The thermostability of Taq polymerase is required during the annealing phase of PCR. View Available Hint(s) O True O False Submit

Answer 1

A.ans:-Ligase.

The polymerase chain reaction is a reaction in which amplification of specific DNA sequences is carried out in vitro.DNA is essential in PCR as it is needed to be amplified.primers are the small chemically synthesised oligonucleotides of about 10-18 nucleotides that are complementary to a region of template DNA.The purpose of deoxynucleotide triphosphates they are building blocks of new stranded DNA.They are of 4 types :-dATP,dCTP,dGTP,dTTP.there is no use of ligase due to absence of RNA primers and okazaki fragments during process of PCR.so ,1st option is correct.

B.False.

Because thermostable taq polymerase required in extension not in annealing.In annealing 2 sets of primers are added which anneal to the 3’ end of each separated strand.primers act as initiators of replication.In extension taq polymerase extends the primers by adding nucleotides complementary to the template provides in the reaction.