Read the passage carefully to answer the questions given below.
Some strains of Bacillus thuringiensis produce proteins that kill certain insects such as lepidopterans (tobacco budworm, armyworm), coleopterans (beetles) and dipterans (flies, mosquitoes). In Bacillus thuringiensis 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. Using conventional methods of diagnosis (serum and urine analysis, etc.) early detection is not possible. Recombinant DNA technology, Polymerase Chain Reaction (PCR) and Enzyme Linked Immuno-sorbent Assay (ELISA) are some of the techniques that serve the purpose of early diagnosis. The first clinical gene therapy was given in 1990 to a 4-year old girl with adenosine deaminase (ADA) deficiency. This enzyme is crucial for the immune system to function. The disorder is caused due to the deletion of the gene for adenosine deaminase. RNAi takes place in all eukaryotic organisms as a method of cellular defense. This method involves silencing of a specific mRNA due to a complementary dsRNA molecule that binds to and prevents translation of the mRNA.
Some strains of Bacillus thuringiensis produce proteins that do not kill certain organisms -
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Crustaceans
The proteins of Bacillus thuringiensis kill certain insects. The passage names three insect groups they kill. Crustaceans are arthropods, but they are not insects.
Option (1) Crustaceans — Not killed by Bt proteins. Crabs, prawns and their relatives are not among the groups the Bt toxin acts on.
Option (2) Dipterans — Killed by Bt proteins.
Option (3) Lepidopterans — Killed by Bt proteins.
Option (4) Coleopterans — Killed by Bt proteins.
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 22-05-2025 (Slot 1) and on 20-05-2025 (Slot 1).