Explain recombinant DNA technology and its applications.
How to lay out the answer. Follow the frame, then write it in your own words.
1 · Open in two lines. Recombinant DNA technology (genetic engineering) joins a gene from one organism into the DNA of another. The host then copies the gene and makes its protein.
2 · Draw the cloning diagram. [Diagram: plasmid and gene cut by the same restriction enzyme → sticky ends joined by ligase → recombinant plasmid → into E. coli → selection on antibiotic → clones making the product]
3 · Tools.
Restriction endonucleases (scissors).
DNA ligase (glue).
Vectors: plasmids, phages.
Host: E. coli, yeast; marker genes for selection.
4 · Steps.
Isolate the gene (or make cDNA).
Cut gene and vector with the same enzyme.
Ligate to form recombinant DNA.
Transform host cells.
Select, clone and harvest the product.
5 · Applications.
Health: human insulin, growth hormone, hepatitis B vaccine.
Food and agriculture: golden rice, Bt cotton, recombinant chymosin.
6 · Significance. Gives pure human proteins in bulk and improves crops. Raises safety and ethical concerns (allergy, gene flow, labelling), regulated in India by GEAC.
7 · Nutrition link. Golden rice targets vitamin A deficiency; recombinant insulin serves people with diabetes.
8 · Close in one line. Sum up recombinant DNA technology as a tool that turns cells into factories for useful proteins.
Scoring tip: One clean flow diagram with the enzyme names written on the arrows covers half the marks.
Write-up practice
The check looks for key words only. It does not grade your answer and never writes it for you.