State and explain the principles of the Polymerase Chain Reaction (PCR)

Firstly, PCR is used to amplify DNA so that it can be used in analysis. It is particularly useful in processes like forensic science to identify DNA samples left behind at a crime scene. The process begins with a sample of the DNA being mixed with DNA nucleotides, DNA primers, Magnesium ions and the thermostable enzyme Taq DNA Polymerase. This mixture is then heated to around 95 degrees celcius to denature the DNA strand and break the hydrogen bonds between the two DNA strands. Then the mixture is cooled as this allows the DNA Primers to anneal to each DNA strand. This is important as now the Taq DNA polymerase can bind to the DNA primer and elongate the chain in the 5' to 3' direction and produce new identical double-stranded DNA. The Magnesium ions act as cofactors to the enzyme Taq DNA Polymerase.Whilst the process repeats in cycles, the amount of DNA increases exponentially.

VP
Answered by Vinaykumar P. Biology tutor

3207 Views

See similar Biology A Level tutors

Related Biology A Level answers

All answers ▸

Describe the stages of Transcription


What is the importance of the 'refractory period' after an action potential has been generated?


How does the sliding filament theory work?


How does the structure of glycogen relate to its function?


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

MyTutor is part of the IXL family of brands:

© 2025 by IXL Learning