Read the following passage carefully and answer the given questions.
Insulin consists of two short polypeptide chains- chain A and chain B, that are linked together by disulphide bridges. Some strains of Bacillus thuringiensis produce proteins that kill certain insects such as lepidopterans, coleopterans and dipterans. Bt toxin protein is converted into an active form of toxin due to the alkaline pH of the gut which solubilise the crystals. 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 (α-1-antitrypsin) used to treat emphysema. 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. (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.
Transgenic animals that produce useful biological products such as human protein (α-1-antitrypsin) used to treat the disorder:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Emphysema
Transgenic animals carry a foreign gene in their DNA. They can be made to produce useful biological products. The passage gives the example of human protein α-1-antitrypsin, used to treat emphysema. Emphysema is a lung disease in which the alveolar walls are damaged, so the area for gas exchange falls. In 1997, the first transgenic cow, Rosie, produced milk containing human alpha-lactalbumin.
Option (1) Adenosine deaminase (ADA) deficiency — Incorrect. ADA deficiency is an immune disorder treated by gene therapy, the first case in 1990, not by α-1-antitrypsin.
Option (2) Cystic fibrosis — Incorrect. Transgenic models are used to study it, but α-1-antitrypsin is not its treatment.
Option (3) Phenylketonuria — Incorrect. Phenylketonuria is an inborn error of metabolism in which the body cannot convert phenylalanine to tyrosine. It is not treated with α-1-antitrypsin.
Option (4) Emphysema — Correct. Transgenic animals are used to make useful biological products. The human protein α-1-antitrypsin, made by transgenic animals, is used to treat emphysema.
Note 1: 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.
Note 2: A similar question was also asked in CUET (UG) 2025 on 02-06-2025 (Slot 2) and on 20-05-2025 (Slot 2).