(a) How it is possible to detect a disease before its symptoms appear?

(b) How do GMOs differ from hybrid and explain the process?

(c) Name the source of Taq polymerase. Explain its advantages.

OR

(a) Explain biopiracy and biopatent.

(b) Explain how gene expression can be controlled by RNA with an example.

(c) Which enzyme is most commonly used for crop improvement in genetic engineering?

(a)It can be done by molecular diagnosis. The methods used are rDNA technology, PCR and ELISA. Diagnosis using PCR: Sample from the suspected organism for the development of a disease is collected. The DNA of pathogen is isolated. It is amplified through PCR and by using probes which can hybridized with the DNA of pathogen, early diagnosis of the pathogen that causes a disease can be detected.

(b) Genetically modified organism has only the desirable genes of donor organism but not all the genes of the donor. A hybrid has not only some desirable genes but also some undesired genes. GMO is formed through rDNA technology and hybrid is formed by hybridization or cross between unlike parents.
(c) Taq polymerase is a thermostable DNA polymerase of a thermophilic bacterium Thermus aquaticus, which is optimally active at 70 – 80⁰C.
OR 

Biopiracy : Usage of bioresources by others without prior permission from countries and people concerned without paying compensation.

Biopatent: It is a legal document that allows the patent holder to prevent others using his invention for a particular period of time.

In RNAi the gene expression is controlled by guide RNA by forming double stranded RNA by pairing with passenger RNA. The double stranded RNA is cut into fragments by dicer. The ds fragments are associated with RISC which selectively destroys the passenger RNA fragment. This technique is used to develop resistance in tobacco to root knot nematode Meloidogyne incognitia.

 Restriction enzymes and Ligases are used for incorporating the desired genes of donor organisms into the genome of host plant in crop improvement through rDNA technology to increase the yield and quality of the produce.