Assertion (A):
Transgenic mice are being developed to test the safety of vaccines, such as the polio vaccine.
Reason (R):
If transgenic mice are found to be reliable for vaccine safety testing, they could replace the use of monkeys, reducing ethical and practical concerns.

[Biotechnology-and-its-Applications] [class-xii ]

• (A) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion
• (B) Both Assertion and Reason are true, but Reason is not the correct explanation of Assertion
• (C) Assertion is true but Reason is false
• (D) Assertion is false but Reason is true
Correct Option: A  [ A ]

Remark: Transgenic animals are used for vaccine safety testing (e.g., the polio vaccine). The primary benefit and driving reason for this research is the potential to replace monkeys, which are currently used for mandatory batch testing, addressing ethical concerns.

Assertion (A):
In mammals, insulin is synthesized as a pro-hormone containing the A, B, and C peptides.
Reason (R):
The C peptide is essential for linking the A and B chains in the pro-hormone and is only removed during the processing stage to form the fully mature and functional insulin molecule.

[Biotechnology-and-its-Applications] [class-xii ]

• (A) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion
• (B) Both Assertion and Reason are true, but Reason is not the correct explanation of Assertion
• (C) Assertion is true but Reason is false
• (D) Assertion is false but Reason is true
Correct Option: A  [ A ]

Remark: Insulin is initially synthesized as pro-insulin. The C peptide is the extra stretch that connects chains A and B, and its enzymatic removal is required to convert the inactive pro-hormone into the mature, functional insulin hormone.

Assertion (A):
Transgenic animals are designed to serve as excellent models for studying the pathogenesis and treatment of human diseases.
Reason (R):
Transgenic models currently exist for complex human diseases such as cancer, cystic fibrosis, rheumatoid arthritis, and Alzheimer’s disease.

[Biotechnology-and-its-Applications] [class-xii ]

• (A) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion
• (B) Both Assertion and Reason are true, but Reason is not the correct explanation of Assertion
• (C) Assertion is true but Reason is false
• (D) Assertion is false but Reason is true
Correct Option: A  [ A ]

Remark: Transgenic animals are engineered by altering genes to mimic human disease states, enabling researchers to better understand disease mechanisms and test new therapies. Specific models for diseases like cancer and Alzheimer’s are mentioned.

Assertion (A):
Bt cotton has reduced the reliance of farmers on chemical pesticides.
Reason (R):
The Bt toxin gene is cloned from the bacteria Bacillus thuringiensis and expressed in cotton plants, acting as an internal bio-pesticide.

[Biotechnology-and-its-Applications] [class-xii ]

• (A) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion
• (B) Both Assertion and Reason are true, but Reason is not the correct explanation of Assertion
• (C) Assertion is true but Reason is false
• (D) Assertion is false but Reason is true
Correct Option: A  [ A ]

Remark: Bt toxin provides resistance against insects (pest-resistant crops), thereby reducing the amount of chemical pesticides farmers need to use. The gene is incorporated into the plant genome to act as a bio-pesticide.

Assertion (A):
The Indian Patents Bill was recently amended by the Parliament.
Reason (R):
The amendment was necessary to address issues of biopiracy and the unauthorized exploitation of India's bio-resources and associated traditional knowledge.

[Biotechnology-and-its-Applications] [class-xii ]

• (A) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion
• (B) Both Assertion and Reason are true, but Reason is not the correct explanation of Assertion
• (C) Assertion is true but Reason is false
• (D) Assertion is false but Reason is true
Correct Option: A  [ A ]

Remark: The amendment of the Indian Patents Bill was a legislative action taken in response to the growing global realisation of injustice and inadequate compensation relating to the exploitation of bio-resources and traditional knowledge.

Assertion (A):
The C peptide is essential for linking the A and B chains in pro-insulin.
Reason (R):
The C peptide is present in the mature, functional insulin molecule, maintaining the correct structure via disulphide bonds.

[Biotechnology-and-its-Applications] [class-xii ]

• (A) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion
• (B) Both Assertion and Reason are true, but Reason is not the correct explanation of Assertion
• (C) Assertion is true but Reason is false
• (D) Assertion is false but Reason is true
Correct Option: C  [ C ]

Remark: A is True: The C peptide is the extra stretch in the pro-hormone that links chains A and B. R is False: The C peptide is removed during maturation and is *not* present in the mature, functional insulin.

Assertion (A):
The apical and axillary meristems of a plant are usually free from viral infection.
Reason (R):
This phenomenon allows scientists to use meristem culture to recover healthy, virus-free plants from an infected mother plant.

[Biotechnology-and-its-Applications] [class-xii ]

• (A) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion
• (B) Both Assertion and Reason are true, but Reason is not the correct explanation of Assertion
• (C) Assertion is true but Reason is false
• (D) Assertion is false but Reason is true
Correct Option: A  [ A ]

Remark: Even if a plant is virus-infected, the rapidly dividing meristem cells (apical and axillary) often remain virus-free, allowing their isolation and *in vitro* growth to regenerate healthy plants.

Assertion (A):
Transgenic animals are designed to increase our understanding of the role of complex factors in normal physiology, like insulin-like growth factor.
Reason (R):
Altering the genes related to these factors allows scientists to study the resulting biological effects, thereby elucidating the factor's role in the body.

[Biotechnology-and-its-Applications] [class-xii ]

• (A) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion
• (B) Both Assertion and Reason are true, but Reason is not the correct explanation of Assertion
• (C) Assertion is true but Reason is false
• (D) Assertion is false but Reason is true
Correct Option: A  [ A ]

Remark: Transgenic animals serve as models to study normal physiology, development, and gene regulation. By manipulating specific genes (e.g., insulin-like growth factor), the biological consequences reveal the factor's function.

Assertion (A):
The Green Revolution successfully tripled the world's food supply.
Reason (R):
Despite increased food supply, the use of improved crop varieties and agrochemicals alone was insufficient to sustain the demands of the rapidly growing human population.

[Biotechnology-and-its-Applications] [class-xii ]

• (A) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion
• (B) Both Assertion and Reason are true, but Reason is not the correct explanation of Assertion
• (C) Assertion is true but Reason is false
• (D) Assertion is false but Reason is true
Correct Option: A  [ A ]

Remark: The Green Revolution tripled supply but was not enough to feed the growing population. Limitations included the cost of agrochemicals and the inability of existing varieties to yield further increases, prompting the need for biotechnology.

Assertion (A):
Genetic modification is used to increase the efficiency of mineral usage by plants.
Reason (R):
Improved mineral efficiency helps prevent the early exhaustion of soil fertility by reducing the plants’ demand for nutrients.

[Biotechnology-and-its-Applications] [class-xii ]

• (A) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion
• (B) Both Assertion and Reason are true, but Reason is not the correct explanation of Assertion
• (C) Assertion is true but Reason is false
• (D) Assertion is false but Reason is true
Correct Option: A  [ A ]

Remark: Genetic modification has been implemented to enhance the efficiency of mineral usage by plants, which directly prevents the soil from losing its fertility too quickly, thereby linking A and R.