Q.Explain with the help of one example how genetically modified plants can:

Genetic modification allows scientists to introduce specific traits into plants that either protect them from pests or boost their nutrient content, addressing two major agricultural challenges.

(a) Reducing chemical pesticides: Bt cotton and Bt corn are classic examples. The bacterium Bacillus thuringiensis produces a protein toxin (Bt toxin) that is lethal to certain insect larvae but harmless to humans and other animals. Scientists isolate the gene encoding this toxin and insert it into the plant's genome. The genetically modified plant now produces the Bt toxin in its tissues. When insect pests like bollworms feed on the plant, they ingest the toxin and die. This built-in resistance means farmers spray far fewer chemical insecticides, cutting costs and environmental damage. …

The promise of genetic modification lies in its ability to address two of agriculture's most pressing challenges: the environmental and health costs of chemical inputs, and the hidden hunger caused by micronutrient deficiencies. By inserting specific genes into crop plants, scientists can confer traits that either protect the plant from pests or enrich its nutritional profile. Both applications rest on the same principle—introducing a foreign gene that codes for a desirable protein—but the outcomes serve very different purposes.

Reducing Chemical Pesticide Use: The Bt Cotton Example

Chemical pesticides have long been the farmer's weapon against insect pests, but they come at a steep price: they poison beneficial insects, contaminate soil and water, and pose health risks to farm workers and consumers. Genetically modified crops offer an elegant alternative by turning the plant itself into a pest-resistant organism.

The most celebrated example is Bt cotton. Scientists isolated a gene from the soil bacterium Bacillus thuringiensis (Bt) that codes for a crystal protein toxic to certain insect larvae, particularly the bollworm—a devastating pest of cotton. When this Bt gene is inserted into the cotton plant's genome, every cell of the plant begins producing the Bt toxin protein. When a bollworm larva feeds on any part of the plant—leaf, bud, or boll—it ingests the toxin, which binds to receptors in its gut, paralyzes its digestive system, and kills it within days.

The result is dramatic. Farmers growing Bt cotton can slash their use of chemical insecticides—sometimes by more than half—because the plant is continuously protected from within. There is no need for repeated spraying, no risk of pesticide drift, and no accumulation of toxic residues in the environment. The economic and ecological benefits are substantial: lower input costs, reduced labor, and a healthier farm ecosystem.

Enhancing Nutritional Value: The Golden Rice Example

Malnutrition is not always about the quantity of food; often it is about quality. Millions of people, especially in developing countries, depend on a single staple crop—rice—that fills their stomachs but leaves them deficient in essential vitamins and minerals. Vitamin A deficiency alone causes blindness in hundreds of thousands of children each year and weakens immune systems, making common infections deadly. …

Method — one worked mechanism per sub-part, kept separate

(a) Reduce pesticides: Bt cotton — the cry gene from Bacillus thuringiensis is inserted into cotton, so the plant itself produces the insecticidal Cry protein; insects feeding on it die, so farmers spray far less chemical pesticide. …