Question

Which of the following is not required in PCR?
A. DNA primer
B. DNA template
C. RNA primer
D. Taq polymerase

Answer 1

Hint:- A primer is a short chain of nucleic acid that allows sequence synthesis as a starting point. They are structured such that the target region (the region that should be copied) is flanked. That is, sequences that will allow them to bind to opposite strands of the template strand are given.

Complete step-by-step solution:-
Option A is correct. For a PCR reaction, a DNA primer is not needed. The non-availability of DNA primers is the reason why RNA primers should be used in PCR. The DNA Primase enzyme, which is nothing but RNA polymerase much like mRNA, readily synthesises the RNA primers complementary to the cellular DNA.
Option B is incorrect. The DNA Template Strand (also known as the antisense strand) has been one of the DNA strands that occurs during gene transcription after the enzyme DNA helicase is unwound. The template strand is called the DNA strand from which the mRNA is built. The prototype strand runs in the direction of 3' to 5'.
Option C is incorrect. Every primer is a brief piece of RNA complementary to the original DNA strand. DNA polymerase can't copy the DNA without a primer. In short, when DNA needs to be copied, RNA primers act as a DNA polymerase starting site.
Option D is incorrect. Taq DNA Polymerase is an extremely thermostable polymerase of recombinant DNA. It is named after the heat-tolerant bacterium from which it isolates itself, Thermus aquaticus. The Taq Polymerase has a molecular weight of 94kD and amplifies DNA up to 5 kb with an elongation velocity of 0.9-1.2kb / min at 70-75 °C.
So, the correct answer is Option A.

Note:- DNA cloning for sequencing, gene cloning and editing, gene mutagenesis, creation of DNA-based phylogenies or functional gene analysis, diagnosis and monitoring of inherited diseases, amplification of ancient DNA, genetic fingerprint analysis for DNA profiling (for example, forensic science and parentage testing) and pathogen detection are all applications of the technique.