Read the following paragraph and answer the given questions.
RNAi takes place in all eukaryotic organisms as a method of cellular defense. The source of this complementary RNA could be from an infection by viruses having RNA genomes or mobile genetic elements (transposons) that replicate via an RNA intermediate. Insulin from an animal source, though caused some patients to develop allergy or other types of reactions to the foreign protein. Insulin consists of two short polypeptide chains: chain A and chain B, that are linked together by disulphide bridges. Transgenic mice are being developed for use in testing the safety of vaccines before they are used on humans. Transgenic mice are being used to test the safety of the polio vaccine. If successful and found to be reliable, they could replace the use of monkeys to test the safety of batches of the vaccine. Specific Bt toxin genes were isolated from Bacillus thuringiensis and incorporated into the several crop plants such as cotton. The choice of genes depends upon the crop and the targeted pest, as most Bt toxins are insect-group specific. The toxin is coded by a gene cryIAc named cry. There are a number of them, for example, the proteins encoded by the genes cryIAc and cryIIAb control the cotton bollworms, that of cryIAb controls corn borer.
Identify the incorrect fact about the genetic modification?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → It has decreased the nutritional value of food, e.g., golden rice, i.e., Vitamin ‘A’ enriched rice.
Genetic modification changes the genes of an organism by manipulation. In crops, every benefit it gave is an improvement, so the statement that speaks of a loss is the incorrect one.
Option (1) It has made crops more tolerant to abiotic stresses (cold, drought, salt, heat). — A correct fact. Stress tolerance is one of the listed benefits: such crops still give a yield when it is cold, dry, salty or hot.
Option (2) It has helped to reduce post harvest losses. — A correct fact. Fewer losses after harvest is a listed benefit: less of the crop is lost after it is picked.
Option (3) It has decreased the nutritional value of food, e.g., golden rice, i.e., Vitamin ‘A’ enriched rice. — An incorrect fact. GM has enhanced the nutritional value of food. Golden rice is the example: it is enriched with vitamin A. NTA changed one word, and one word decides the answer; read each word before you mark.
Option (4) It has reduced reliance on chemical pesticides (pest-resistant crops). — A correct fact. Pest-resistant crops such as Bt cotton need fewer pesticides.
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.
NCERT Extract:
Biotechnological Applications in Agriculture – “… Plants, bacteria, fungi and animals whose genes have been altered by manipulation are called Genetically Modified Organisms (GMO). GM plants have been useful in many ways. Genetic modification has: (i) made crops more tolerant to abiotic stresses (cold, drought, salt, heat). (ii) reduced reliance on chemical pesticides (pest-resistant crops). (iii) helped to reduce post harvest losses. (iv) increased efficiency of mineral usage by plants (this prevents early exhaustion of fertility of soil). (v) enhanced nutritional value of food, e.g., golden rice, i.e., Vitamin ‘A’ enriched rice.”