Question

1. PCR takes advantage of the steps of DNA replication. Match each step of PCR with the protein that the PCR step has replaced.

Answer 1

PCR or Polymerase Chain Reaction is an molecular technique to amplify a single copy or segment of DNA.

It is a rapid and versatile in-vitro method designed to permit selective amplification of a specific target DNA sequences within a heterogeneous collection of DNA sequences.

The most commonly used equipment in PCR is Thermalcycler also known as PCR machine.

Inside the PCR machine there are small tubes in which all the chemicals are inserted to perform the reaction.

Inside the tubes,we keep:

Taq polymerase,a type of DNA polymerase ;isolated from bacteria Thermus aquaticus which is thermostable i.e. can withstand high temperature upto 94°C.

Primers,are short sequences of nucleotides usually around 20 nucleotides in length.

Primers provides starting point in DNA synthesis and also provides information to choose exact portion for amplification.

DNA template is the segment of original DNA which we want to amplify.

Nucleotides ​​​​​​,basic building blocks used for DNA synthesis.

• PCR involves 3 steps:

Denaturation :This step is typically done at 93-95°C so that the strands get separated resulting in 2 separate strands of DNA.

Annealing :This is done at temperature 50-70°C and this temperature is made low to enable hybridization between primer and templates.

Extension done at 70-75°C where extension or polymerization of strand occurs.

Hope this helps you...Thank you