Biology · Biotechnology: Principles and Processes · NEET
They are used almost as the same thing in NCERT. Genetic engineering is the broad idea of changing an organism's genes on purpose. Recombinant DNA technology is the main method used to do this: it creates recombinant DNA (new combination of DNA), and uses gene cloning and gene transfer. So rDNA technology is the toolbox that makes genetic engineering possible.
'Recombinant' means a NEW combination of DNA that did not exist before, made outside the cell (in vitro). You take DNA from one source (the desired gene) and join it to DNA of another source (a vector). Because two different DNAs are combined into one molecule, the result is called recombinant DNA.
A piece of DNA on its own has no origin of replication, so it cannot copy itself in a new host and would be lost. That is why the gene is joined to a vector (plasmid or bacteriophage), which carries an ori. The vector lets the gene replicate along with it, giving many copies. This is why a vector is a must in rDNA technology.
Stanley Cohen and Herbert Boyer made the first recombinant DNA in 1972 by joining an antibiotic-resistance gene into a native plasmid of Salmonella typhimurium, using restriction enzymes and DNA ligase. This is the classic example of the whole idea. It is covered in detail in the next concept, How the First Recombinant DNA Was Made.
The key tools are restriction enzymes (cut DNA), DNA ligase (joins DNA), polymerase enzymes (copy DNA, used in PCR), vectors (carry the gene), and a host organism (multiplies the rDNA). E. coli is the common host because the recombinant DNA can replicate using the host's own DNA polymerase and make many copies (cloning).
Match the organism with its use in biotechnology: (a) Bacillus (b) Thermus aquaticus (c) Agrobacterium tumefaciens (d) Salmonella typhimurium — with (i) Cloning vector (ii) Construction of first rDNA (iii) DNA polymerase (iv) Cry proteins.
Main steps in the formation of Recombinant DNA are given below. Arrange these steps in the correct sequence: A. Insertion of recombinant DNA into the host cell. B. Cutting of DNA at specific location by restriction enzyme. C. Isolation of desired DNA fragment. D. Amplification of gene of interest using PCR.
Try the real previous-year questions from this chapter — each with the answer and a full solution.
It is the technique of joining DNA from two different sources (a desired gene and a vector) to form a new recombinant DNA molecule that can be copied inside a host cell.
Because the recombinant DNA transferred into E. coli can replicate using the bacterium's own DNA polymerase and quickly make many identical copies, a process called cloning.
Restriction enzymes, polymerase enzymes, DNA ligases, vectors, and a host organism. NCERT lists exactly these five.
No. Recombinant DNA is the actual new DNA molecule formed. Recombinant DNA technology is the whole set of methods used to make, copy and transfer that molecule.
Chapter 9 (Biotechnology: Principles and Processes) is high-weightage, and questions on the meaning, steps, tools and the first rDNA (Cohen and Boyer) are repeatedly asked in NEET.
