Which of the following techniques is NOT listed as serving the purpose of early diagnosis in molecular medicine?

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

• Polymerase Chain Reaction (PCR)
• Enzyme Linked Immuno-sorbent Assay (ELISA)
• Recombinant DNA technology
• Conventional serum and urine analysis
Correct Option: D  [ Conventional serum and urine analysis ]

Remark: Recombinant DNA technology, PCR, and ELISA are techniques used for early diagnosis. Conventional methods (serum and urine analysis) often fail to provide early detection.

PCR (Polymerase Chain Reaction) is routinely used in molecular diagnosis primarily because it can:

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

• Detect antibodies synthesized against a pathogen.
• Amplify nucleic acids, detecting very low concentrations of pathogens before symptoms appear.
• Determine the pathogenicity of the virus.
• Bind radioactive probes to specific mRNA sequences.
Correct Option: B  [ Amplify nucleic acids, detecting very low concentrations of pathogens before symptoms appear. ]

Remark: PCR is a powerful technique routinely used to detect very low concentrations of bacteria or viruses (like HIV in suspected AIDS patients) by amplification of their nucleic acid, even when disease symptoms are not yet visible.

In molecular diagnosis using a radioactive probe and autoradiography, how is a clone having a mutated gene identified?

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

• The probe will show high complementarity with the mutated gene.
• The clone will exhibit intense fluorescence.
• The clone will not appear on the photographic film.
• The gene will be amplified by PCR.
Correct Option: C  [ The clone will not appear on the photographic film. ]

Remark: A single-stranded DNA or RNA probe is allowed to hybridize to its complementary DNA. If the gene is mutated, the probe will not have complementarity, and consequently, the clone having the mutated gene will not appear on the photographic film after autoradiography.

ELISA (Enzyme Linked Immuno-sorbent Assay) is a diagnostic technique based on the principle of:

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

• Gene amplification.
• Antigen-antibody interaction.
• Nucleic acid hybridization.
• Protoplast fusion.
Correct Option: B  [ Antigen-antibody interaction. ]

Remark: ELISA is based on the principle of antigen-antibody interaction. Infection by a pathogen can be detected by identifying the presence of antigens (proteins, glycoproteins) or by detecting antibodies synthesized against the pathogen.

Animals whose DNA has been manipulated to possess and express an extra (foreign) gene are specifically known as:

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

• Somaclones
• Somatic hybrids
• Transgenic animals
• Eukaryotic catalysts
Correct Option: C  [ Transgenic animals ]

Remark: Animals that have had their DNA manipulated to possess and express an extra (foreign) gene are known as transgenic animals.

Over what percentage of all existing transgenic animals are mice?

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

• 50 per cent
• 75 per cent
• 85 per cent
• 95 per cent
Correct Option: D  [ 95 per cent ]

Remark: While transgenic rats, rabbits, pigs, sheep, cows and fish have been produced, over 95 per cent of all existing transgenic animals are mice.

Transgenic animals are specifically designed to study complex factors involved in growth, such as:

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

• Adenosine Deaminase (ADA)
• Alpha-1-antitrypsin
• Insulin-like growth factor
• Pro-insulin
Correct Option: C  [ Insulin-like growth factor ]

Remark: Transgenic animals can be designed to study how genes affect normal functions and development, for example, the study of complex factors involved in growth such as insulin-like growth factor.

Which of the following human diseases is NOT specifically listed in the sources as having an existing transgenic animal model for increasing understanding of its development?

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

• Cancer
• Cystic fibrosis
• Polio
• Rheumatoid arthritis
Correct Option: C  [ Polio ]

Remark: Transgenic models exist for many human diseases such as cancer, cystic fibrosis, rheumatoid arthritis and Alzheimer’s. Polio is mentioned in the context of vaccine safety testing, not as a disease model itself.

Which human protein, produced by transgenic animals, is used to treat emphysema?

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

• Human alpha-lactalbumin
• Alpha-1-antitrypsin
• C peptide
• Growth hormone
Correct Option: B  [ Alpha-1-antitrypsin ]

Remark: Transgenic animals can be created to produce useful biological products, such as the human protein alpha-1-antitrypsin, used to treat emphysema.

Rosie, the first transgenic cow, produced human protein-enriched milk containing how much protein per liter?

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

• 0.6 grams
• 1.2 grams
• 2.4 grams
• 4.8 grams
Correct Option: C  [ 2.4 grams ]

Remark: Rosie, the first transgenic cow (1997), produced human protein-enriched milk (2.4 grams per litre), which contained the human alpha-lactalbumin.