This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of nucleic acids, Subject name: Biochemistry
Enzyme used in PCR is 
Select and explain. 
A. Reverse transcriptase, B. Taq polymerase, C. RNA polymerase, D. None
B: Taq polymerase
Answer: B: Taq polymerase 
Explanation: In step 3 i.e polymerization : New DNA strands are synthesized by Taq polymerase. This enzyme is derived from bacteria Thermus acquaticus that are found in hot springs.Therefore the enzyme is not denatured at high temperature. REFERENCE : DM.VASUDEVAN.TEXTBOOK; SEVENTH EDITION; PAGE NO :638.