Outline the use of polymerase chain reaction (PCR) to copy and amplify minute quantities of DNA.

PCR is a way of producing large quantities of a specific target sequence of DNA.

It is useful when only a small amount of DNA is available for testing  (e.g. crime scene samples of blood, semen, tissue, hair, etc.).


PCR occurs in a thermal cycler and involves a repeat procedure of 3 steps:

1.  Denaturation:  DNA sample is heated to separate it into two strands

2.  Annealing:  DNA primers attach to opposite ends of the target sequence

3.  Elongation:  A heat-tolerant DNA polymerase (Taq) copies the strands 


- One cycle of PCR yields two identical copies of the DNA sequence

Zana Katarina L. IB Biology tutor, IB Maths tutor, IB Psychology tutor

2 years ago

Answered by Zana Katarina, an IB Biology tutor with MyTutor

Still stuck? Get one-to-one help from a personally interviewed subject specialist


Eleanor H.
View profile
£20 /hr

Eleanor H.

Degree: Biochemistry (Bachelors) - Bristol University

Subjects offered: Biology, Chemistry


“ABOUT ME: I am a biochemistry student, currently studying at the University of Bristol, and have had a passion for the natural sciences from a very young age. I am patient, hardworking and experienced, having tutored students in Maths...”

PremiumTiago D. IB Biology tutor, IB Chemistry tutor, Mentoring -Personal St...
View profile
£24 /hr

Tiago D.

Degree: Biological Sciences (Bachelors) - Edinburgh University

Subjects offered: Biology, Chemistry+ 1 more

-Personal Statements-

“I think Biology is a fascinating subject and I am currently studying Biological Sciences at The University of Edinburgh because I am keen to do research in this area.”

Karl R. GCSE Human Biology tutor, A Level Human Biology tutor, GCSE B...
View profile
£22 /hr

Karl R.

Degree: Medicine (Bachelors) - Cambridge University

Subjects offered: Biology, Science+ 7 more

Human Biology
.BMAT (BioMedical Admissions)
-Oxbridge Preparation-
-Medical School Preparation-

“Hi, My name is Karl. I am 19 year old medical student studying at Cambridge. I have completed my first year of study gaining a First overall and ranking 6th best of ~300 medical students in anatomy.  I have been tutoring students (KS3 ...”

About the author

Zana Katarina L. IB Biology tutor, IB Maths tutor, IB Psychology tutor
View profile
£20 /hr

Zana Katarina L.

Degree: Psychology (Bachelors) - Durham University

Subjects offered: Biology, Psychology+ 1 more


“Top tutor from the renowned Russell university group, ready to help you improve your grades.”

MyTutor guarantee

You may also like...

Posts by Zana Katarina

Describe one example of transient polymorphism.

Discuss the relative importance of genetic and cultural evolution in the recent evolution of humans.

Analyze the changes in concentration of atmospheric carbon dioxide using historical records.

Behaviour can be innate because it is genetically based and can be inherited.

Other IB Biology questions

Draw and label a diagram of the carbon cycle to show the processes involved.

What is the difference between meiosis and mitosis?

Outline a basic technique used for gene transfer involving plasmids, a host cell (bacterium, yeast or other cell), restriction enzymes (endonucleases) and DNA ligase.

Explain the process of DNA translation

View IB Biology tutors


We use cookies to improve our service. By continuing to use this website, we'll assume that you're OK with this. Dismiss