Biotechnology and its Applications MCQs for NEET — Zoology Questions with Answers

The NCERT text explains, 'Many transgenic animals are designed to increase our understanding of how genes contribute to the development of disease. These are specially made to serve as models for human diseases so that investigation of new treatments for diseases is made possible.'

Transgenic animals are defined by the introduction of foreign DNA (genes) into their genome, which then expresses the product of that foreign gene. The text repeatedly refers to 'introduction of the portion of DNA (or genes)' to produce various effects or products.

The NCERT text states, 'Transgenic animals are made that carry genes which make them more sensitive to toxic substances than non-transgenic animals... Toxicity testing in such animals will allow us to obtain results in less time.'

The NCERT states under 'Ethical Issues' that 'The manipulation of living organisms by the human race cannot go on any further, without regulation. Some ethical standards are required to evaluate the morality of all human activities that might help or harm living organisms.' This context directly applies to genetic modification.

The text clearly categorizes this under '(iii) Biological products: Medicines required to treat certain human diseases can contain biological products... Transgenic animals that produce useful biological products can be created by the introduction of the portion of DNA (or genes) which codes for a particular product such as human protein ($\alpha$-1-antitrypsin) used to treat emphysema.'

The NCERT states, '(i) Normal physiology and development: Transgenic animals can be specifically designed to allow the study of how genes are regulated, and how they affect the normal functions of the body and its development, e.g., study of complex factors involved in growth such as insulin-like growth factor.' This directly addresses the question.

According to the provided text, 'The activated toxin binds to the surface of midgut epithelial cells and create pores that cause cell swelling and lysis and eventually cause death of the insect.'

The text states that Bt toxin kills 'lepidopterans (tobacco budworm, armyworm), coleopterans (beetles) and dipterans (flies, mosquitoes)'. Hymenopterans are not mentioned.

The text clearly states, 'once an insect ingest the inactive toxin, it is converted into an active form of toxin due to the alkaline pH of the gut which solubilise the crystals.'

The text explains, 'The activated toxin binds to the surface of midgut epithelial cells and create pores that cause cell swelling and lysis and eventually cause death of the insect.'