Grade 12 : Biology | Biotechnology and its Applications

Question 1

A group of agricultural researchers introduced crystal protein genes from Bacillus thuringiensis into cotton plants to control insect pests.

Why does the Bt toxin protein not kill the bacterium that produces it?

Accepted Answer

C) The toxin exists as an inactive protoxin within the bacterial cell

Answer

A) The bacterium is surrounded by an impermeable, thick peptidoglycan wall

Answer

B) The bacterium carries specific antitoxins that neutralize the active toxin

Answer

D) The intracellular pH of the bacterium is highly alkaline

Question 2

Which specific gene encodes a crystal protein that controls the cotton bollworm?

Accepted Answer

B) cryIAc

Answer

A) cryIAb

Answer

C) cryIIAb and cryIAb

Answer

D) pBR322

Question 3

A team of molecular biologists is developing nematode-resistant tobacco plants using gene silencing techniques.

Which vector was utilized to introduce nematode-specific genes into the host tobacco plant to trigger RNA interference (RNAi)?

Accepted Answer

A) Agrobacterium tumefaciens

Answer

B) Escherichia coli plasmid pUC19

Answer

C) Bacteriophage lambda

Answer

D) Retrovirus vector

Question 4

During the synthesis of proinsulin in human pancreatic beta cells, what structural component distinguishes proinsulin from mature, functional insulin?

Accepted Answer

D) Presence of an extra stretch of polypeptide called the C-peptide

Answer

A) Presence of extra disulfide bonds between chain A and chain B

Answer

B) Absence of chain A

Answer

C) Absence of chain B

Question 5

In 1983, the American pharmaceutical company Eli Lilly prepared human insulin using recombinant DNA technology.

How did Eli Lilly successfully assemble mature human insulin?

Accepted Answer

B) Produced chains A and B separately in E. coli and joined them by creating disulfide bonds

Answer

A) Synthesized proinsulin directly in E. coli and excised the C-peptide enzymatically

Answer

C) Cloned the entire human preproinsulin gene directly into mammalian host cells

Answer

D) Extracted inactive proinsulin from transgenic bovine models and modified chain lengths

Question 6

Assertion (A): Adenosine deaminase (ADA) deficiency can be cured permanently if functional ADA cDNA is introduced into bone marrow cells at early embryonic stages.
Reason (R): Lymphocytes cultured in vitro from patient blood have an immortal lifespan and divide continuously inside the body.

Select the correct choice based on the statements above:

Accepted Answer

A) Both (A) and (R) are true, but (R) is not the correct explanation of (A)

Answer

B) (A) is true, but (R) is false

Answer

C) Both (A) and (R) are true, and (R) is the correct explanation of (A)

Answer

D) (A) is false, but (R) is true

Question 7

A four-year-old patient diagnosed with severe combined immunodeficiency due to ADA deficiency received gene therapy in 1990.

What was the main limitation of this lymphocyte-based gene therapy that necessitated periodic infusions?

Accepted Answer

C) The infused genetically engineered lymphocytes have a finite lifespan

Answer

A) The retroviral vector triggered acute host immune rejection

Answer

B) The recombinant cDNA failed to integrate into host chromosomal DNA

Answer

D) ADA enzyme degrades rapidly within the blood plasma within 24 hours

Question 8

In which of the following molecular diagnostic techniques is a single-stranded DNA or RNA tagged with a radioactive molecule (probe) to detect mutated genes?

Accepted Answer

D) Autoradiography following hybridization with a complementary probe

Answer

A) Enzyme-Linked Immunosorbent Assay (ELISA)

Answer

B) Polymerase Chain Reaction alone without hybridization

Answer

C) Agarose gel electrophoresis with ethidium bromide

Question 9

The diagnostic technique ELISA is fundamentally based on which biochemical principle?

Accepted Answer

B) Antigen-antibody interaction

Answer

A) Denaturation and renaturation of double-stranded DNA

Answer

C) Silencing of specific mRNA via dsRNA

Answer

D) Electrophoretic mobility based on charge-to-mass ratio

Question 10

Transgenic animals are engineered to produce human proteins in their milk for the treatment of specific metabolic and systemic human diseases.

Which human protein was successfully produced by the first transgenic cow, Rosie, in 1997?

Accepted Answer

A) Human alpha-lactalbumin

Answer

B) Human alpha-1-antitrypsin

Answer

C) Tissue plasminogen activator

Answer

D) Human erythropoietin

Question 11

The human protein $\alpha$-1-antitrypsin produced through transgenic animal biological factories is clinically used to treat which condition?

Accepted Answer

C) Emphysema

Answer

A) Phenylketonuria

Answer

B) Cystic fibrosis

Answer

D) Rheumatoid arthritis

Question 12

What is the primary role of the Genetic Engineering Appraisal Committee (GEAC) established by the Indian Government?

Accepted Answer

B) To make decisions regarding the validity and safety of GM research and releasing GMOs for public use

Answer

A) To fund and subsidize commercial agricultural biotechnology startups

Answer

C) To sequence microbial genomes to prevent patent litigations abroad

Answer

D) To restrict the export of traditional basmati rice varieties

Question 13

In 1997, an American company was granted patent rights on a crop variety derived from an indigenous Indian crop through the US Patent and Trademark Office.

Which crop was patented after crossing with semi-dwarf varieties to claim an 'invention' or novelty?

Accepted Answer

D) Basmati Rice

Answer

A) Golden Rice

Answer

B) Sharbati Sonora Wheat

Answer

C) Co-419 Sugarcane

Question 14

Which term refers to the unauthorized use of bio-resources and traditional knowledge by multinational companies without proper authorization or compensatory payment?

Accepted Answer

A) Biopiracy

Answer

B) Biofortification

Answer

C) Bioremediation

Answer

D) Biomagnification

Question 15

Assertion (A): RNA interference (RNAi) takes place in all eukaryotic organisms as a method of cellular defense.
Reason (R): It involves silencing of a specific mRNA due to a complementary double-stranded RNA (dsRNA) molecule that prevents translation.

Evaluate both statements and pick the correct option:

Accepted Answer

C) Both (A) and (R) are true, and (R) is the correct explanation of (A)

Answer

A) (A) is true, but (R) is false

Answer

B) (A) is false, but (R) is true

Answer

D) Both (A) and (R) are true, but (R) is not the correct explanation of (A)

Question 16

A clinical diagnostic lab uses PCR to screen asymptomatic patients suspected of carrying low titers of viral pathogens.

Why is PCR effective in detecting infectious diseases before overt symptoms appear?

Accepted Answer

D) It exponentially amplifies minute quantities of target nucleic acids

Answer

A) PCR directly measures pathogen-specific antibody titers in serum

Answer

B) Pathogenic antigens bind irreversibly to Taq polymerase enzymes

Answer

C) PCR converts bacterial proteins into visible dye complexes

Question 17

What physiological effect occurs when an insect pest ingests activated Bt crystalline endotoxin?

Accepted Answer

B) Binding to midgut epithelial cells causing swelling, pore formation, and cell lysis

Answer

A) Neurotoxic inhibition of acetylcholinesterase enzymes

Answer

C) Precipitation of salivary proteins preventing feeding

Answer

D) Disruption of cuticle formation during larval molting

Question 18

Transgenic models are extensively engineered for which of the following biomedical investigations?

Accepted Answer

A) Studying gene regulation, investigating human diseases, and testing vaccine safety

Answer

B) Inducing non-specific chromosomal aberrations in wild populations

Answer

C) Increasing ecosystem biomass through selective predation

Answer

D) Eliminating the necessity of Phase III human clinical drug trials entirely

Question 19

Transgenic 'Golden Rice' was bioengineered specifically to address which nutritional deficiency?

Accepted Answer

C) Vitamin A deficiency causing night blindness

Answer

A) Iron-deficiency anemia

Answer

B) Vitamin C deficiency (Scurvy)

Answer

D) Essential amino acid lysine deficiency

Question 20

Statement I: Transgenic mice are being developed and tested to replace monkeys for batch safety testing of polio vaccines.
Statement II: Toxicity testing using transgenic animals harboring hypersensitive foreign genes allows toxicity results to be obtained in much less time.

Which of the following is correct regarding Statement I and Statement II?

Accepted Answer

B) Both Statement I and Statement II are true

Answer

A) Statement I is false, but Statement II is true

Answer

C) Both Statement I and Statement II are false

Answer

D) Statement I is true, but Statement II is false

Set 4Grade 12 : Biology | Biotechnology and its Applications