Assertion (A): Polymerase Chain Reaction (PCR) is highly effective for the detection of mutations in genes in suspected cancer patients. Reason (R): PCR works by amplifying the nucleic acid sequence of interest, enabling the detection of even very low concentrations of the genetic material, which is critical for early diagnosis.
PCR is a powerful tool for molecular diagnosis, capable of identifying genetic disorders and gene mutations (like those in cancer). Its high sensitivity allows the amplification of minute nucleic acid amounts, facilitating early and reliable detection.
Question 462 of 494
📘 CLASS XII
Assertion (A): Enzyme replacement therapy for ADA deficiency involves the injection of functional ADA into the patient. Reason (R): Enzyme replacement therapy is a completely curative approach for ADA deficiency because it provides the necessary functional enzyme.
A is True: Enzyme replacement therapy involves administering functional ADA via injection. R is False: Both bone marrow transplantation and enzyme replacement therapy are explicitly stated to be *not* completely curative.
Question 463 of 494
📘 CLASS XII
Assertion (A): The Indian Parliament recently cleared an amendment to the Indian Patents Bill. Reason (R): This amendment was cleared to take into consideration issues of patent terms, emergency provisions, and the unauthorized exploitation of bio-resources and traditional knowledge.
The Indian Parliament has cleared the second amendment to the Indian Patents Bill. This action was taken specifically to address the growing realization of injustice, inadequate compensation, and the need to prevent unauthorized exploitation (biopiracy) of Indian bio-resources.
Question 464 of 494
📘 CLASS XII
Assertion (A): The GEAC (Genetic Engineering Approval Committee) was established by the Indian Government primarily to regulate GM research. Reason (R): GEAC is responsible for assessing the safety of introducing genetically modified organisms (GMOs) for public services due to the potential for unpredictable ecological results from genetic modification.
Genetic modification requires strict regulation because of the risk of unpredictable environmental consequences. GEAC was established precisely to make decisions regarding the validity of GM research and ensuring the public safety of GM organisms.
Question 465 of 494
📘 CLASS XII
Assertion (A): When using a nucleic acid probe to detect a mutation, the clone containing the mutated gene will not appear on the photographic film after autoradiography. Reason (R): The mutation prevents the probe, which is complementary to the normal sequence, from hybridizing, thus failing to retain the radioactive tag for detection.
The probe, typically single-stranded and radioactive, requires complementarity to hybridize. A mutation disrupts this complementarity, preventing hybridization. Since the probe doesn't bind, the radioactive signal is absent, and the clone site is dark on the film.
Question 466 of 494
📘 CLASS XII
Assertion (A): Bt toxin is highly effective against a wide range of insect pests, providing broad-spectrum resistance to GM crops. Reason (R): The choice of a specific Bt toxin gene (like cryIAc or cryIAb) is crucial because most Bt toxins are highly insect-group specific, targeting specific orders like lepidopterans or coleopterans.
A is False: Bt toxins are *not* broad-spectrum; they kill only certain insects, such as lepidopterans, coleopterans, and dipterans. R is True: Bt toxins are insect-group specific, requiring careful gene selection based on the targeted pest (e.g., *cryIAb* for corn borer).
Question 467 of 494
📘 CLASS XII
Assertion (A): Insulin for diabetic patients was previously extracted from the pancreas of slaughtered cattle and pigs. Reason (R): This animal-sourced insulin often caused immune responses, such as allergies or other types of reactions, in human patients due to the foreign protein nature.
A is True: Insulin was historically sourced from slaughtered animals. R is True and explains A: Using non-human insulin led to patient allergies or reactions because the foreign protein triggered an unwanted immunological response.
Question 468 of 494
📘 CLASS XII
Assertion (A): Micro-propagation allows the rapid production of thousands of plants that are referred to as somaclones. Reason (R): Somaclones are plants that are genetically identical to the original parent plant, having been asexually propagated from a small explant using tissue culture methods.
Micro-propagation is the mass asexual production of plants *in vitro*. Since these plants are derived from a single explant and are produced asexually, they are genetic replicas (somaclones) of the parent plant.
Question 469 of 494
📘 CLASS XII
Assertion (A): Transgenic animals are generally engineered to be less sensitive to toxic substances than non-transgenic animals for safety testing. Reason (R): This modified sensitivity allows researchers to test the toxicity of drugs and chemicals effectively over a shorter period.
A is False: Transgenic animals used for toxicity/safety testing are made *more* sensitive to toxic substances compared to normal animals. R is False: The purpose of increasing sensitivity is to obtain results in *less* time, not because lower sensitivity speeds up the process.
Question 470 of 494
📘 CLASS XII
Assertion (A): The milk produced by the transgenic cow Rosie was nutritionally balanced for human babies because it contained human alpha-lactalbumin. Reason (R): Rosie produced milk containing 2.4 grams per litre of human protein, making it a more superior biological product than natural cow-milk.
Rosie was the first transgenic cow (1997) and produced human protein-enriched milk. The inclusion of human alpha-lactalbumin at a concentration of 2.4 g/L made the milk nutritionally superior and more balanced for human infant consumption than regular cow milk.
