Chapter 10: Biotechnology and its Applications Assertion-Reason Questions | biology Class 12 CBSE

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 1

Logic Check

Assertion (A): Bt toxin does not kill the Bacillus thuringiensis bacteria that produce it. Reason (R): The Bt toxin exists as an inactive protoxin inside the bacterium and is only activated by the alkaline pH of the insect midgut.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 2

Logic Check

Assertion (A): Meristematic tissue from a virus-infected plant can be used to obtain virus-free plants through tissue culture. Reason (R): The meristem (apical and axillary) is free of virus even in an infected plant because viruses spread through vascular tissue which is absent in rapidly dividing meristematic cells.

Reasoning Options

ByteNotes

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 3

Logic Check

Assertion (A): Recombinant human insulin does not cause allergic reactions in diabetic patients. Reason (R): Recombinant human insulin is structurally identical to naturally secreted human insulin and is free from foreign protein contaminants.

Reasoning Options

ByteNotes

Assertion-Reason

Hard difficulty • Check the statement and reason

Hard

Question 4

Logic Check

Assertion (A): Gene therapy using retroviral vectors in lymphocytes provides a permanent cure for ADA deficiency. Reason (R): Lymphocytes are non-dividing cells with an infinite lifespan, so they permanently maintain the introduced ADA gene.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 5

Logic Check

Assertion (A): Golden Rice has been genetically modified to produce Vitamin C in its endosperm. Reason (R): Scientists introduced genes for beta-carotene biosynthesis into rice to address Vitamin A deficiency.

Reasoning Options

ByteNotes

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 6

Logic Check

Assertion (A): The process of micropropagation produces somaclones. Reason (R): In micropropagation, explants are cultured in a nutrient medium to produce thousands of genetically identical plants, all derived from the same parent plant.

Reasoning Options

ByteNotes

Assertion-Reason

Hard difficulty • Check the statement and reason

Hard

Question 7

Logic Check

Assertion (A): The cryIAb gene product is used to control cotton bollworms in Bt cotton. Reason (R): Different cry gene products are insect-group specific; cryIAb encodes a protein that specifically controls corn borer, while cryIAc and cryIIAb control cotton bollworms.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 8

Logic Check

Assertion (A): RNAi is a method of cellular defence present in all eukaryotic organisms. Reason (R): RNAi involves silencing of specific mRNA by a double-stranded RNA molecule complementary to the target mRNA, thereby preventing its translation.

Reasoning Options

ByteNotes

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 9

Logic Check

Assertion (A): Transgenic animals are used as disease models to study human diseases like cancer and Alzheimer's. Reason (R): Transgenic animals carry altered human genes that predispose them to specific diseases, helping researchers understand disease mechanisms and test new treatments.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 10

Logic Check

Assertion (A): Somatic hybridisation allows plant breeders to create hybrids between sexually incompatible plant species. Reason (R): Somatic hybridisation involves the fusion of protoplasts (cells with cell wall removed) from different plant varieties, bypassing the need for sexual reproduction.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 11

Logic Check

Assertion (A): Insulin cannot be administered orally to diabetic patients. Reason (R): Insulin is a protein and would be digested by proteases in the gastrointestinal tract before it can be absorbed into the bloodstream.

Reasoning Options

ByteNotes

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 12

Logic Check

Assertion (A): GM crops have been developed for tolerance to abiotic stresses such as drought, cold, and salinity. Reason (R): Genes responsible for abiotic stress tolerance have been isolated and introduced into crop plants using recombinant DNA technology.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 13

Logic Check

Assertion (A): Biopiracy involves the unauthorised use of biological resources from biodiversity-rich countries by multinational companies. Reason (R): Biopiracy benefits indigenous communities by ensuring their traditional knowledge is recognised and rewarded.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 14

Logic Check

Assertion (A): The pomato somatic hybrid was commercially very successful. Reason (R): Somatic hybridisation by fusing tomato and potato protoplasts always yields plants with the desired combination of commercially valuable traits.

Reasoning Options

ByteNotes

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 15

Logic Check

Assertion (A): Viruses are used as vectors in gene therapy to deliver therapeutic genes into patient cells. Reason (R): Viruses naturally insert their genetic material into host cells as part of their replication cycle, a property exploited in gene therapy.

Reasoning Options

ByteNotes

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 16

Logic Check

Assertion (A): PCR is used to detect HIV infection even when the viral load is very low. Reason (R): PCR amplifies tiny amounts of pathogen DNA or RNA, making it detectable even in early infection when antibody-based tests may be negative.

Reasoning Options

ByteNotes

Assertion-Reason

Hard difficulty • Check the statement and reason

Hard

Question 17

Logic Check

Assertion (A): Bt toxin crystals produced by Bacillus thuringiensis are equally toxic to all insects. Reason (R): Different cry gene products are insect-group specific, meaning each Bt toxin targets only a particular group of insects.

Reasoning Options

ByteNotes

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 18

Logic Check

Assertion (A): Whole plants can be regenerated from explants in tissue culture. Reason (R): Every cell of a plant contains the complete genetic information (genome) of the plant and possesses totipotency.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 19

Logic Check

Assertion (A): The Green Revolution was sufficient to feed the entire growing human population. Reason (R): The Green Revolution tripled food supply through improved crop varieties, fertilisers, pesticides, and better management, but population growth and equitable food distribution remained challenges.

Reasoning Options

ByteNotes

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 20

Logic Check

Assertion (A): Recombinant DNA technological processes have made mass production of safe therapeutic drugs possible. Reason (R): Recombinant therapeutics are produced in controlled systems and are free from the risk of introducing animal pathogens to patients.

Reasoning Options

ByteNotes

Chapter sections

Chapter 10: Biotechnology and its Applications | Assertion-Reason

Assertion (A): Bt toxin does not kill the Bacillus thuringiensis bacteria that produce it. Reason (R): The Bt toxin exists as an inactive protoxin inside the bacterium and is only activated by the alkaline pH of the insect midgut.

Assertion (A): Recombinant human insulin does not cause allergic reactions in diabetic patients. Reason (R): Recombinant human insulin is structurally identical to naturally secreted human insulin and is free from foreign protein contaminants.

Assertion (A): Gene therapy using retroviral vectors in lymphocytes provides a permanent cure for ADA deficiency. Reason (R): Lymphocytes are non-dividing cells with an infinite lifespan, so they permanently maintain the introduced ADA gene.

Assertion (A): Golden Rice has been genetically modified to produce Vitamin C in its endosperm. Reason (R): Scientists introduced genes for beta-carotene biosynthesis into rice to address Vitamin A deficiency.

Assertion (A): The process of micropropagation produces somaclones. Reason (R): In micropropagation, explants are cultured in a nutrient medium to produce thousands of genetically identical plants, all derived from the same parent plant.

Assertion (A): The cryIAb gene product is used to control cotton bollworms in Bt cotton. Reason (R): Different cry gene products are insect-group specific; cryIAb encodes a protein that specifically controls corn borer, while cryIAc and cryIIAb control cotton bollworms.

Assertion (A): RNAi is a method of cellular defence present in all eukaryotic organisms. Reason (R): RNAi involves silencing of specific mRNA by a double-stranded RNA molecule complementary to the target mRNA, thereby preventing its translation.

Assertion (A): Transgenic animals are used as disease models to study human diseases like cancer and Alzheimer's. Reason (R): Transgenic animals carry altered human genes that predispose them to specific diseases, helping researchers understand disease mechanisms and test new treatments.

Assertion (A): Somatic hybridisation allows plant breeders to create hybrids between sexually incompatible plant species. Reason (R): Somatic hybridisation involves the fusion of protoplasts (cells with cell wall removed) from different plant varieties, bypassing the need for sexual reproduction.

Assertion (A): Insulin cannot be administered orally to diabetic patients. Reason (R): Insulin is a protein and would be digested by proteases in the gastrointestinal tract before it can be absorbed into the bloodstream.

Assertion (A): GM crops have been developed for tolerance to abiotic stresses such as drought, cold, and salinity. Reason (R): Genes responsible for abiotic stress tolerance have been isolated and introduced into crop plants using recombinant DNA technology.

Assertion (A): Biopiracy involves the unauthorised use of biological resources from biodiversity-rich countries by multinational companies. Reason (R): Biopiracy benefits indigenous communities by ensuring their traditional knowledge is recognised and rewarded.

Assertion (A): The pomato somatic hybrid was commercially very successful. Reason (R): Somatic hybridisation by fusing tomato and potato protoplasts always yields plants with the desired combination of commercially valuable traits.

Assertion (A): Viruses are used as vectors in gene therapy to deliver therapeutic genes into patient cells. Reason (R): Viruses naturally insert their genetic material into host cells as part of their replication cycle, a property exploited in gene therapy.

Assertion (A): PCR is used to detect HIV infection even when the viral load is very low. Reason (R): PCR amplifies tiny amounts of pathogen DNA or RNA, making it detectable even in early infection when antibody-based tests may be negative.

Assertion (A): Bt toxin crystals produced by Bacillus thuringiensis are equally toxic to all insects. Reason (R): Different cry gene products are insect-group specific, meaning each Bt toxin targets only a particular group of insects.

Assertion (A): Whole plants can be regenerated from explants in tissue culture. Reason (R): Every cell of a plant contains the complete genetic information (genome) of the plant and possesses totipotency.

Assertion (A): Recombinant DNA technological processes have made mass production of safe therapeutic drugs possible. Reason (R): Recombinant therapeutics are produced in controlled systems and are free from the risk of introducing animal pathogens to patients.

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