What is the common term for the plants resulting from micro-propagation, as they are genetically identical to the original plant?

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

• Somatic hybrids
• Protoplasts
• Somaclones
• Transgenic plants
Correct Option: C  [ Somaclones ]

Remark: The method of producing thousands of plants through tissue culture is called micro-propagation. Each resulting plant is genetically identical to the original plant and is called a somaclone.

The use of agrochemicals like fertilizers and pesticides helped the Green Revolution succeed, but for farmers in the developing world, a major drawback was that these chemicals were often:

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

• Ineffective against new pests.
• Too expensive.
• Harmful only to crops, not pests.
• Not readily available.
Correct Option: B  [ Too expensive. ]

Remark: Increased yields during the Green Revolution were partly due to the use of agrochemicals (fertilisers and pesticides). However, agrochemicals are often too expensive for farmers in the developing world.

Which of the following conditions is an abiotic stress that Genetically Modified (GM) crops have been made more tolerant to?

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

• Viral infection
• Salt
• Fungal attack
• Nematode infestation
Correct Option: B  [ Salt ]

Remark: Genetic modification has made crops more tolerant to abiotic stresses such as cold, drought, salt, and heat.

What is the primary function of the C peptide in insulin synthesis in mammals, including humans?

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

• It links the A and B chains together.
• It functions as the mature hormone.
• It is an extra stretch in the pro-hormone that is removed during maturation.
• It initiates the formation of disulphide bridges.
Correct Option: C  [ It is an extra stretch in the pro-hormone that is removed during maturation. ]

Remark: Insulin is synthesized as a pro-hormone, which contains an extra stretch called the C peptide. This C peptide is not present in the mature insulin and is removed during maturation.

Before the advent of genetically engineered insulin, where was the insulin used for diabetic patients extracted from?

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

• Synthetic chemical reactors.
• Pancreas of slaughtered cattle and pigs.
• Human cadavers.
• Genetically modified yeast cells.
Correct Option: B  [ Pancreas of slaughtered cattle and pigs. ]

Remark: Insulin used for diabetes was earlier extracted from the pancreas of slaughtered cattle and pigs.

Which of the following is a drawback associated with insulin isolated from animal sources for human use?

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

• Inability to link A and B chains.
• Requirement for constant refrigeration.
• Risk of developing allergy or other immune reactions to the foreign protein.
• Difficulty in mass production.
Correct Option: C  [ Risk of developing allergy or other immune reactions to the foreign protein. ]

Remark: Insulin from an animal source caused some patients to develop allergy or other types of reactions to the foreign protein.

Why is it necessary for a person undergoing gene therapy for ADA deficiency to receive periodic infusions of genetically engineered lymphocytes?

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

• The lymphocytes are immortal, but they need periodic growth hormone.
• The introduced functional ADA gene is defective and degrades quickly.
• The genetically engineered lymphocytes are not immortal and die after some time.
• The retroviral vector used is toxic and needs frequent flushing.
Correct Option: C  [ The genetically engineered lymphocytes are not immortal and die after some time. ]

Remark: Lymphocytes engineered with functional ADA cDNA are returned to the patient, but since these cells are not immortal, the patient requires periodic infusion of such genetically engineered lymphocytes.

Adenosine Deaminase (ADA) deficiency is caused by the deletion of the gene for this enzyme, which is crucial for the function of the:

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

• Circulatory system.
• Skeletal system.
• Endocrine system.
• Immune system.
Correct Option: D  [ Immune system. ]

Remark: The first clinical gene therapy was given for ADA deficiency. This enzyme is crucial for the immune system to function.

In the context of agriculture, which of the following is NOT one of the three options listed for increasing food production?

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

• Agro-chemical based agriculture.
• Genetically engineered crop-based agriculture.
• Organic agriculture.
• Conventional breeding for high-yield varieties.
Correct Option: D  [ Conventional breeding for high-yield varieties. ]

Remark: The three options for increasing food production are: (i) agro-chemical based agriculture; (ii) organic agriculture; and (iii) genetically engineered crop-based agriculture. Conventional breeding failed to keep pace with demand.

In the production of the hybrid plant "Pomato" via somatic hybridisation, the protoplasts fused were from which two plants?

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

• Potato and Tomato.
• Potato and Maize.
• Tomato and Chilli.
• Potato and Wheat.
Correct Option: A  [ Potato and Tomato. ]

Remark: Somatic hybridisation has been achieved by fusing protoplasts of tomato and potato to form new hybrid plants, resulting in the formation of pomato.