BIOTECHNOLOGY : PRINCIPLES AND PROCESSES
Read the following passage carefully and answer the given questions.
Biotechnology deals with large scale production and marketing of products and processes using live organisms, cells or enzymes. Modern biotechnology using genetically modified organisms was made possible only when man learnt to alter the chemistry of DNA and construct recombinant DNA. This key process is called recombinant DNA technology or genetic engineering. This process involves the use of enzymes, viral vectors to carry the foreign DNA into host organisms, expression of the foreign gene, purification of the gene product, and finally making a suitable formulation for marketing. Restriction endonucleases are used in genetic engineering to form ‘recombinant’ molecules of DNA, which are composed of DNA from different sources/genomes. Gene cloning allows us to isolate and introduce only one or a set of desirable genes without introducing undesirable genes into the target organism. The ability to multiply copies of antibiotic resistance gene in E. coli was called cloning of antibiotic resistance gene in E. coli. In PCR, multiple copies of the gene (or DNA) of interest is synthesised in vitro using two sets of primers (small chemically synthesised oligonucleotides that are complementary to the regions of DNA) and the enzyme DNA polymerase.
Which one of the followings is not a step involved in the process of recombinant DNA technology?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Hybridisation using labelled VNTR probe
Recombinant DNA technology joins DNA from two sources and makes many copies of it. Its main steps are: isolation of the DNA, cutting the DNA at specific places with restriction enzymes, amplifying the gene of interest by PCR, joining it to a vector, putting this into a host, growing the host cells and getting the product.
(1) Amplification of gene of interest using PCR — A step of recombinant DNA technology. PCR (polymerase chain reaction) makes many copies of the gene to be cloned.
(2) Cutting DNA at specific locations — A step of recombinant DNA technology. Restriction enzymes cut the DNA and the vector at specific places.
(3) Isolation of the genetic material (DNA) — A step of recombinant DNA technology. The DNA must be pure before it is cut.
(4) Hybridisation using labelled VNTR probe — Not a step of recombinant DNA technology. It is a step of DNA fingerprinting. The labelled VNTR (variable number of tandem repeats) probe hybridises with the VNTR sequences of a person’s DNA to find out the pattern that is unique to that person.
Note: The passage is taken from NCERT. NTA has put lines of the NCERT text together to make it. Most CUET (UG) questions come straight from NCERT, so study the book line by line, including figures and their titles.