Question

Which one is an example of restriction endonuclease?
A. pBR322
B. EcoR1
C. pUC18
D. pSC101

Answer 1

Hint:-The branch of science which deals with techniques of using live organisms or enzymes from organisms to produce products and processes useful to humans is called Biotechnology.
The two core techniques that developed modern biotechnology are named as - genetic engineering and chemical engineering.

Complete answer:-Genetic engineering includes all the techniques to alter the chemistry of genetic material, to introduce these into host organisms and thus change the phenotype of an organism.
The technique of genetic engineering which includes the creation of recombinant DNA, use of gene cloning and gene transfer and used to introduce one or a set of desirable genes into the target organism.
Genetic engineering or the recombinant DNA technology can be accomplished only with the presence of certain key tools namely- restriction enzymes, polymerase enzymes, ligases, vectors and the host organism.
Restriction enzymes are a member of ‘nucleases’, a larger class of enzymes. There are two types of nucleases namely - exonucleases and endonucleases. Exonucleases remove nucleotides from the ends of DNA molecules whereas endonucleases make cuts at specific positions within the DNA.
DNA molecules contain some specific sites called palindromic sites. Restriction endonucleases recognise those sites and cut the DNA strand at a site away from the centre of the palindrome site but between the same two bases on the opposite stands.
The most commonly used restriction endonuclease is named as EcoR1, which is derived from Escherichia coli bacteria.
pBR322 is the commonly used vector in recombinant DNA technology. Also, pUC18 and pSC101 are used as vectors in recombinant DNA technology.

Thus the correct answer is option B, EcoR1.

Note:- The discovery of restriction endonucleases enabled the cutting of DNA at specific locations. The cut piece of DNA is then linked with the plasmid DNA. These plasmid DNA acts as vectors to transfer the piece of DNA attached to it.
To link the alien DNA, the vector needs to have very few, preferably single, recognition sites for commonly used restriction enzymes.