- Which of the following is NOT a feature of genetically modified (GM) crops?
a) Resistance to pests
b) Increased shelf life
c) Production of bioethanol
d) Enhanced nutritional value
Answer: c) Production of bioethanol
Explanation: GM crops are engineered for various traits, such as pest resistance, enhanced nutritional value (like Golden Rice with Vitamin A), and increased shelf life. However, bioethanol production involves using crops for biofuel purposes and is not a direct feature of genetic modification in crops.
- Bt cotton is resistant to which pest?
a) Aphids
b) Whiteflies
c) Cotton bollworm
d) Spider mites
Answer: c) Cotton bollworm
Explanation: Bt cotton is genetically modified to produce the Cry proteins from Bacillus thuringiensis, which are toxic to the larvae of the cotton bollworm, reducing crop loss due to pest attacks.
- Which of the following is NOT used in genetic engineering?
a) Restriction enzymes
b) DNA ligase
c) DNA polymerase
d) Amylase
Answer: d) Amylase
Explanation: Genetic engineering involves manipulating DNA using restriction enzymes (to cut DNA), DNA ligase (to join DNA fragments), and DNA polymerase (for replication). Amylase, an enzyme that breaks down starch into sugars, is not involved in genetic engineering.
- Which technique is used for DNA fingerprinting?
a) PCR
b) RFLP
c) ELISA
d) Gel electrophoresis
Answer: b) RFLP
Explanation: Restriction Fragment Length Polymorphism (RFLP) is used in DNA fingerprinting to detect variations in DNA sequences by cutting DNA with restriction enzymes and separating fragments using gel electrophoresis. This helps in identifying individuals based on their unique DNA patterns.
- Which of the following is a disadvantage of genetically modified crops?
a) Reduced pesticide use
b) Increased crop yield
c) Development of resistance in pests
d) Enhanced nutritional content
Answer: c) Development of resistance in pests
Explanation: One potential disadvantage of GM crops, like Bt cotton, is that over time, pests may evolve resistance to the toxins produced by the crops. This can reduce the effectiveness of the genetic modification and require the use of additional pest control measures.
- Which of the following organisms is used to produce insulin in genetic engineering?
a) Saccharomyces cerevisiae
b) Escherichia coli
c) Aspergillus niger
d) Pseudomonas putida
Answer: b) Escherichia coli
Explanation: Insulin is produced using recombinant DNA technology by inserting the human insulin gene into Escherichia coli. This bacterium then produces insulin, which is harvested for medical use, especially for patients with diabetes.
- Agrobacterium tumefaciens is widely used in biotechnology for:
a) Bioremediation
b) Gene cloning in plants
c) Protein synthesis
d) Nitrogen fixation
Answer: b) Gene cloning in plants
Explanation: Agrobacterium tumefaciens is a bacterium that naturally transfers part of its DNA (T-DNA) into plant cells, causing crown gall disease. In biotechnology, it is harnessed as a vector to insert desired genes into plant genomes for the development of genetically modified plants.
- Which of the following is not a method of introducing recombinant DNA into host cells?
a) Microinjection
b) Electroporation
c) Heat shock
d) Centrifugation
Answer: d) Centrifugation
Explanation: Methods like microinjection, electroporation, and heat shock are commonly used to introduce recombinant DNA into host cells. Centrifugation, on the other hand, is used to separate mixtures based on density and is not a method for DNA transformation.
- What is the role of Ti plasmid in biotechnology?
a) It is used to induce mutations.
b) It serves as a vector for gene transfer in plants.
c) It enhances protein production in microbes.
d) It protects plants from viruses.
Answer: b) It serves as a vector for gene transfer in plants.
Explanation: The Ti plasmid (Tumor-inducing plasmid) from Agrobacterium tumefaciens is used in plant biotechnology as a vector to deliver genes into plant cells. It integrates part of its DNA into the plant genome, making it a useful tool for producing genetically modified plants.
- The process by which identical copies of an organism are produced through non-sexual means is called:
a) Hybridization
b) Cloning
c) Grafting
d) Pollination
Answer: b) Cloning
Explanation: Cloning is the process of creating identical genetic copies of an organism through asexual reproduction, bypassing the need for fertilization. This can be done via techniques like somatic cell nuclear transfer (SCNT) in animals or tissue culture in plants.
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