Assertion (A):
Transgenic animals are used for vaccine safety testing.
Reason (R):
Transgenic mice are currently being developed to test the safety of the polio vaccine and potentially replace the use of monkeys.

[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 mice are actively being developed for vaccine safety assessment, specifically cited for the polio vaccine. If reliable, they offer an ethical and practical replacement for mandatory monkey testing.

Assertion (A):
Molecular diagnosis using PCR is crucial for detecting diseases like HIV and cancer.
Reason (R):
PCR is highly sensitive, allowing amplification of nucleic acid when the pathogen concentration is low, before symptoms are visible.

[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: PCR is superior to conventional methods for early diagnosis (HIV, cancer) because its amplification capability can detect the presence of trace amounts of pathogen or mutated DNA before the disease progresses to the symptomatic stage.

Assertion (A):
Transgenic animals are used for chemical safety testing.
Reason (R):
These animals are engineered to be more sensitive to toxic substances, which accelerates the testing process and reduces the time required to obtain results.

[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 made more sensitive to toxins than non-transgenic animals to quickly gauge the safety of drugs and chemicals. This modification allows results to be obtained in less time, fulfilling the purpose of toxicity testing.

Assertion (A):
ELISA is a molecular diagnostic technique that detects infection based on antigen-antibody interaction.
Reason (R):
Infection can be detected by identifying the presence of the pathogen (antigen) or the specific antibodies synthesized against it by the host.

[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: ELISA (Enzyme Linked Immuno-sorbent Assay) utilizes the highly specific binding between antigens (pathogen components) and host antibodies, allowing for the reliable detection of either component to confirm infection status.

Assertion (A):
Biopiracy predominantly harms the financial interests of industrialized nations.
Reason (R):
Industrialized nations are generally poor in biodiversity and traditional knowledge, making them targets of unauthorized exploitation by multinational companies.

[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: D  [ D ]

Remark: A is False: Biopiracy involves the unauthorized use of bio-resources and traditional knowledge, primarily belonging to developing and underdeveloped nations. R is False: Industrialized nations are financially rich but poor in biodiversity/traditional knowledge, while developing nations are rich in these resources.

Assertion (A):
ADA deficiency can be permanently cured by enzyme replacement therapy.
Reason (R):
The only permanent cure for ADA deficiency involves introducing the functional ADA gene into cells at an early embryonic stage.

[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: D  [ D ]

Remark: A is False: Enzyme replacement therapy is not a completely curative approach. R is True: Permanent cure is achieved by gene introduction at the early embryonic stage.

Assertion (A):
Somaclones are plants produced asexually through micro-propagation.
Reason (R):
Somaclones are genetically identical to the original parent plant because they are generated from an explant, relying on the process of totipotency.

[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: Micro-propagation uses the totipotency of plant cells (explant) to regenerate thousands of genetically identical plants in a short period. These identical, asexually derived offspring are called somaclones.

Assertion (A):
The Bt toxin protein exists as an inactive protoxin within the bacterium *Bacillus thuringiensis*.
Reason (R):
The protein crystals remain inactive in the bacterium because the toxin only becomes activated in the presence of the high pH (alkaline conditions) found in the insect gut.

[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 Bt toxin is produced as an inactive protoxin within the bacteria. The high alkaline pH of the insect midgut solubilizes these crystals and converts the protoxin into its active, toxic form, which is why the bacteria are not harmed.

Assertion (A):
Recombinant therapeutics are safer and more effective than similar products isolated from non-human sources.
Reason (R):
Recombinant products are structurally identical to natural human proteins and thus do not trigger unwanted immunological responses or risk infection transmission.

[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: Recombinant DNA technology allows mass production of therapeutics identical to human proteins, eliminating the risk of allergic reactions and infections previously associated with products derived from animal sources.

Assertion (A):
The production of human insulin via rDNA technology requires the separate production of the A and B polypeptide chains.
Reason (R):
The bacterial host (*E. coli*) does not possess the enzymatic machinery required to remove the C peptide from pro-insulin, necessitating external synthesis of the 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: A  [ A ]

Remark: Since bacteria cannot perform the post-translational modification (C-peptide removal) necessary to convert pro-insulin into mature insulin, Eli Lilly engineered the chains separately, extracted them, and joined them *in vitro* using disulphide bonds.