PCR Process and DNA Amplification — NEET Biology
✅ Asked in NEET 2026The enzyme extends the primers using the nucleotides provided in the reaction and the genomic DNA as template. If the process of replication of DNA is repeated many times, the segment of DNA can be amplified to approximately billion times, i.e., 1 billion copies are made. Such repeated amplification is achieved by the use of a thermostable DNA polymerase (isolated from a bacterium, Thermus aquaticus), which remain active during the high temperature induced denaturation of double stranded DNA. The amplified fragment if desired can now be used to ligate with a vector for further cloning.
The NTA tests students' understanding of how PCR amplifies DNA segments billions of times using primers, DNA polymerase, and repeated cycles of heating and cooling. Students often confuse the role of Taq polymerase (thermostable enzyme from Thermus aquaticus) with regular DNA polymerase, or forget why high temperature doesn't denature it. Key trap: mistaking the number of copies produced or thinking regular polymerase works in PCR. Remember: Taq polymerase remains active at high temperatures because it's thermostable, allowing continuous DNA replication cycles without enzyme degradation. This is why billions of copies are generated—each cycle doubles the DNA, achieving exponential amplification essential for molecular biology applications.
This paragraph was tested 7 times in NEET.
Identify the correct sequence of steps in each cycle of Polymerase Chain Reaction:
Following are the steps involved in the process of PCR: (NEET 2024) A. Denaturation B. Amplification (~1 billion times) C. Denaturation D. Treatment with Taq polymerase and deoxynucleotides E. Extension Choose the correct sequence:
Thermostable DNA polymerase used in PCR was isolated from: (NEET 2023)
During the process of gene amplification using PCR, very high temperature is not maintained in the beginning, then which of the following step in PCR will be affected first? (NEET 2021)
Which of the following is a correct sequence of steps in a PCR (Polymerase Chain Reaction)? (NEET 2021)
The correct order of steps in Polymerase Chain Reaction (PCR) is: (NEET 2018)
The Taq polymerase enzyme is obtained from: (NEET 2016 Phase 1)
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