Biotechnology and its Applications Test - 5

Cry gene produce protein crystals in the insects gut as alkaline medium renders it insoluble and the activated toxin binds to surface of midgut epithelial cells and creates pores that cause cell swelling and death of the insect.

Conventional breeding programme takes several years to develops a new variety of crop. By use of biotechnology, required gene can be directly inserted into host plant to get required result.

Gene coding form higher nutrient and resistance to disease can be incorporated in crop.

Use of genetically modified crops may increase crop production many times without use of chemicals and fertilizers.

Hirudin is an anticlotting agent that prevents blood clotting. It is obtained from secretion of leeches. The gene encoding hirudin is synthesized to prevent blood clotting during surgery.

Gram positive bacteria retains the Gram stain after washing with iodine. Bacillus thuringiensis is a gram positive bacteria so, gives positive results.

Different Cry gene is effective against different insects. Cry IAb is not effective against the cotton bollworm as Cry genes are specific. CryIAb is effective against corn borer.

Bt toxins leads to swelling and lysis of the pores of the epithelial lining as it binds to the receptors on the gut and create pores that cause cell swelling and cause death of insects.

Cry genes can be transferred into another plants also as they are present in plasmid of the bacterium which can be easily separated and combined with gene of other crop plants.

Bacillus thuringiensis bacterium forms protein crystals during particular phase of growth. The crystal of toxic protein has insecticidal protein. This protein get activated in alkaline medium in the gut of insects and kills them.

Genetically modified plants are more tolerant to abiotic stress like cold, drought, heat etc. GM plants enhance nutritional value of food such as vitamin A enriched rice. Genetically modified plants are not carcinogenic or cancer causing.