NEET Biotechnology and Its Applications Test

• Answer: (3) Joining DNA fragments
• Explanation: DNA ligase is an enzyme used to join DNA fragments by forming phosphodiester bonds between the sugar-phosphate backbones of the DNA.

• Answer: (1) It is used to create genetically modified organisms (GMOs).
• Explanation: Recombinant DNA technology is used to manipulate DNA and create GMOs by inserting genes from one organism into the DNA of another organism, making it widely applicable in agriculture, medicine, and research.

• Answer: (2) Cystic fibrosis
• Explanation: Gene therapy introduces a functional gene to correct genetic defects, such as those causing cystic fibrosis.

• Answer: (1) Escherichia coli
• Explanation: Human insulin is produced in Escherichia coli by inserting the human insulin gene into bacterial plasmids.

• Answer: (4) All of the above
• Explanation: Biofertilizers like Rhizobium, Azotobacter, and Mycorrhiza enhance soil fertility by fixing nitrogen or improving nutrient absorption.

• Answer: (2) DNA from two different sources combined
• Explanation: Recombinant DNA involves combining DNA from two different sources to create a new genetic combination used in genetic engineering.

• Answer: (2) It is synthesized from an RNA template.
• Explanation: cDNA (complementary DNA) is synthesized from an RNA template using reverse transcriptase and lacks introns.

• Answer: (3) Cloning animals
• Explanation: While recombinant DNA technology has applications in insulin production, genetically modified crops, and gene therapy, animal cloning typically involves other techniques, such as somatic cell nuclear transfer.

• Answer: (3) DNA ligase
• Explanation: DNA ligase is referred to as the molecular glue because it joins DNA fragments by forming phosphodiester bonds.

• Answer: (4) All of the above
• Explanation: Biotechnology improves agriculture through pest-resistant crops, biofertilizers, and transgenic plants with enhanced traits.

• Answer: (2) Exploitation of biological resources without permission
• Explanation: Biopiracy occurs when companies or researchers use indigenous biological resources without proper authorization or compensation.

• Answer: (2) A mouse with a specific gene inactivated
• Explanation: Knockout mice are used in research to study the role of specific genes by inactivating them.

• Answer: (1) FISH
• Explanation: FISH uses fluorescent probes to locate specific DNA sequences on chromosomes.

• Answer: (2) Vitamin A
• Explanation: Golden rice is genetically modified to produce β-carotene, a precursor of vitamin A, to combat vitamin A deficiency in populations with limited access to this nutrient.

• Answer: (2) Synthesize DNA from RNA
• Explanation: Reverse transcriptase is an enzyme that synthesizes complementary DNA (cDNA) from an RNA template, commonly used in the study of gene expression.

• Answer: (2) Oncomouse
• Explanation: The Oncomouse was genetically modified to carry an activated oncogene, making it a model for cancer research.

• Answer: (4) All of the above
• Explanation: Gene therapy faces challenges like immune responses, limitations in treating complex disorders, and high costs.

• Answer: (1) Identify transformed cells
• Explanation: Selectable markers, such as antibiotic resistance genes, help identify cells that have taken up the plasmid vector.

• Answer: (4) All of the above
• Explanation: Transgenic animals serve in research, medicine, and agriculture for studying genes, creating therapies, and disease modeling.

• Answer: (4) All of the above
• Explanation: Plasmids are circular DNA molecules used in cloning because they replicate independently, have selectable markers, and contain restriction sites for gene insertion.

• Answer: (2) Vector for gene transfer
• Explanation: The Ti plasmid from Agrobacterium tumefaciens is used as a vector to transfer genes into plant cells, particularly for creating genetically modified plants.

• Answer: (1) Polymerase Chain Reaction
• Explanation: PCR is a technique used to amplify specific DNA sequences, making millions of copies of a particular segment of DNA in a short time.

• Answer: (2) They transfer genes into plants.
• Explanation: Ti plasmids, derived from Agrobacterium tumefaciens, are used in plant genetic engineering to transfer genes into plant cells.

• Answer: (4) All of the above
• Explanation: Various methods, including electroporation, gene guns, and microinjection, are used to create genetically modified plants by introducing foreign genes into plant cells.

• Answer: (2) Restriction endonuclease
• Explanation: Restriction enzymes recognize specific DNA sequences and cut at these sites, facilitating DNA manipulation.

• Answer: (2) Vitamin A deficiency
• Explanation: Golden rice contains β-carotene, which the body converts into vitamin A, addressing vitamin A deficiency in developing countries.

• Answer: (2) Bacillus thuringiensis
• Explanation: Bt cotton is genetically modified to express a toxin from Bacillus thuringiensis that is lethal to specific insect pests.

• Answer: (1) Agrobacterium
• Explanation: The first genetically modified plant was produced using Agrobacterium tumefaciens, which naturally transfers DNA to plant cells, making it a tool in plant genetic engineering.

• Answer: (1) PCR
• Explanation: Polymerase Chain Reaction (PCR) is used to amplify specific DNA sequences rapidly.

• Answer: (4) All of the above
• Explanation: These methods are commonly used in genetic engineering to introduce DNA into cells for transformation.

• Answer: (1) Translation in nematode.
• Explanation: RNA interference (RNAi) is a process by which RNA molecules inhibit gene expression, typically by causing the degradation of mRNA or inhibiting its translation. In nematodes, RNAi primarily affects translation, thereby preventing the synthesis of certain proteins.

• Answer: (1) Identical copies of a gene
• Explanation: Gene cloning generates multiple copies of the same gene, allowing for further study and application.

• Answer: (2) Convert RNA into DNA
• Explanation: Reverse transcriptase synthesizes complementary DNA (cDNA) from an RNA template, commonly used in gene expression studies.

• Answer: (2) To initiate transcription
• Explanation: A promoter is a DNA sequence where RNA polymerase binds to start transcription, ensuring gene expression.

• Answer: (1) Extraction, Amplification, Ligation, Transformation
• Explanation: The typical steps in gene cloning include extracting the DNA, amplifying the gene of interest, ligating it into a vector, and transforming it into a host organism for replication.

• Answer: (1) Gel electrophoresis
• Explanation: Gel electrophoresis separates DNA fragments based on size using an electric field.

Answer: (1) To identify successful transformants

Explanation: Selectable markers, like antibiotic resistance genes, help identify cells that have successfully incorporated the desired genetic material

• Answer: (4) All of the above
• Explanation: Techniques like RNAi, gene knockout, and antisense RNA prevent the expression of specific genes, silencing them.

• Answer: (1) Penicillin
• Explanation: Secondary metabolites like penicillin are not directly involved in growth or reproduction but serve ecological functions.

• Answer: (1) Enzyme-Linked Immunosorbent Assay
• Explanation: ELISA is a technique used to detect the presence of specific antigens or antibodies in a sample using enzyme-labeled immunoassay methods.

• Answer: (4) Organism
• Explanation: Cloning vectors are used to carry foreign DNA into host cells for cloning. Organisms are not vectors themselves but may be hosts for cloned genes.

• Answer: (2) Modifying cells outside the body and reintroducing them
• Explanation: In ex vivo gene therapy, cells are removed from the patient, modified in the laboratory, and then reintroduced into the body.

• Answer: (4) All of the above
• Explanation: Bioinformatics integrates computational tools to analyze data in genomics, proteomics, and drug discovery.

• Answer: (3) To detect specific DNA or RNA sequences
• Explanation: Probes are short, labeled sequences of DNA or RNA used to identify complementary sequences through hybridization.

• Answer: (4) All of the above
• Explanation: Selectable markers such as antibiotic resistance genes, fluorescent proteins, and reporter genes are used to identify cells that have successfully incorporated foreign DNA.

• Answer: (4) The toxin causes cell wall damage to Bacillus thuringiensis.
• Explanation: Bt toxin is produced by Bacillus thuringiensis and is toxic to certain insects, not to the bacterium itself. The toxin disrupts the gut cells of insects, causing their death. It is also used in genetically modified crops to protect against pests.

• Answer: (1) Electroporation
• Explanation: Electroporation is a technique used to introduce recombinant DNA into cells by applying an electrical field, making the cell membrane temporarily permeable.

• Answer: (2) Reverse transcriptase
• Explanation: Reverse transcriptase synthesizes complementary DNA (cDNA) from mRNA, commonly used in molecular cloning and gene expression studies.

Answer: (4) All of the above

Explanation: Cloning vectors like pBR322, lambda phage, and cosmids are used to transfer foreign DNA into host cells

• Answer: (1) They have foreign DNA integrated into their genome.
• Explanation: Transgenic organisms are those that contain DNA from a different species, integrated into their genome. This is a key feature in genetically modified organisms (GMOs).