BioTechnology (UPSC) PREVIOUS YEAR Mcq (PRELIMS)
Q.1 ) Other than resistance of pests, what are the prospects for which genetically engineered plants have been created? (2012)
- To enable them to withstand drought.
- To increase the nutritive value of the produce.
- To enable them to grow and do photosynthesis in spaceships and space stations.
- To increase their shelf life
Select the correct answer using the codes given below”
(a) 1 and 2 only
(b) 3 and 4 only
(c) 1, 2 and 4 only
(d) 1, 2, 3 and 4
ANSWER: C
Explanation:
- To enable them to withstand drought: Genetic engineering has been employed to create plants with enhanced drought tolerance. This involves introducing genes that allow the plants to conserve water more efficiently or adapt to water scarcity conditions. This trait is particularly valuable in regions where water resources are limited or in the face of changing climatic conditions.
- To increase the nutritive value of the produce: Genetic modification can be used to enhance the nutritional content of plants. For example, scientists can introduce genes that produce higher levels of essential vitamins, minerals, or proteins. This can address nutritional deficiencies in certain crops, providing consumers with more nutritious food options.
- To enable them to grow and do photosynthesis in spaceships and space stations: While this specific application may not be widespread, the idea of genetically engineered plants for space agriculture has been explored. The concept involves creating plants that can thrive in the controlled environments of spaceships or space stations, providing a potential source of fresh food for astronauts during extended space missions.
- To increase their shelf life: Genetic engineering can be used to improve the shelf life of fruits and vegetables. For instance, the inhibition of certain enzymes responsible for the ripening process can slow down the aging of produce, reducing spoilage and waste. This can be beneficial for both producers and consumers by extending the period during which the products remain fresh.
Q.2) With reference to ‘stem cells’, frequently in the news, which of the following statements is/are correct? (2012)
- Stem cells can be derived from mammals only .
- Stem cells can be used for screening new drugs.
- Stem cells can be used for medical therapies.
Select the correct answer using the codes given below:
(a) 1 and 2 only
(b) 2 and 3 only
(c) 3 only
(d) 1, 2 and 3
ANSWER: B
Explanation:
- Stem cells can be derived from mammals only: This statement is incorrect. While stem cells are commonly derived from mammals, including humans, they can also be found in other organisms, such as birds, fish, and even some adult insects.
- Stem cells can be used for screening new drugs: This statement is correct. Stem cells are valuable in drug discovery and screening. Scientists can use stem cells to test the safety and effectiveness of new drugs before clinical trials.
- Stem cells can be used for medical therapies: This statement is correct. Stem cells have significant potential for use in various medical therapies, especially in regenerative medicine. They can be directed to differentiate into specific cell types to replace or repair damaged tissues and organs.
Q.3) What are the reasons for the people’s resistance to the introduction of Bt brinjal in India? (2012)
- Bt brinjal has been created by inserting a gene form a soil fungus into its genome.
- The seeds of Bt brinjal are terminator seeds and therefore, the farmers have to buy the seeds before every season from the seed companies.
- There is an apprehension that the consumption of Bt brinjal may have adverse impact on health.
- There is some concern that the introduction of Bt brinjal may have adverse effect on the biodiversity,
Select the correct answer using the codes given below:
(a) 1, 2 and 3 only
(b) 2 and 3 only
(c) 3 and 4 only
(d) 1, 2, 3 and 4
ANSWER: C
Explanation:
- Bt brinjal is genetically modified to express a toxin from the bacterium Bacillus thuringiensis (Bt) to confer resistance against certain pests.
- The seeds of Bt brinjal are terminator seeds, and therefore, farmers have to buy the seeds before every season from the seed companies: This statement is incorrect. Bt brinjal seeds are not terminator seeds. Terminator seeds are genetically modified to render the seeds sterile, preventing farmers from saving and replanting them.
- There is an apprehension that the consumption of Bt brinjal may have an adverse impact on health: This statement is correct. Concerns about the potential impact of consuming genetically modified organisms (GMOs) on human health have been raised by some individuals and groups.
- There is some concern that the introduction of Bt brinjal may have an adverse effect on biodiversity: This statement is correct. The introduction of genetically modified crops can raise concerns about their impact on biodiversity, as it may affect non-target organisms and disrupt ecosystems.
Q.4) Recombinant DNA technology (Genetic Engineering) allows genes to be transferred (2013)
- across different species of plants
- from animals to plants
- from microorganisms to higher organisms
Select the correct answer using the codes given below.
(a) 1 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3
ANSWER: D
Explanation:
Recombinant DNA technology, also known as Genetic Engineering, allows genes to be transferred:
- Across different species of plants: This is correct. Genetic engineering enables the transfer of genes between different species, creating genetically modified plants.
- From animals to plants: This is correct. Genetic material can be transferred from animals to plants, leading to the development of genetically modified organisms (GMOs).
- From microorganisms to higher organisms: This is correct. Recombinant DNA technology allows the transfer of genes from microorganisms, such as bacteria or yeast, to higher organisms, including plants and animals.
Q.5) Mycorrhizal biotechnology has been used in rehabilitating degraded sites because mycorrhiza enables the plants to (2013)
- resist drought and increase absorptive area
- tolerate extremes of pH
- resist disease infestation
Select the correct answer using the codes given below.
(a) 1 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3
ANSWER: D
Explanation:
Mycorrhizal biotechnology involves the use of mycorrhizal fungi to enhance plant growth, particularly in degraded or stressed environments. Mycorrhizae form a symbiotic relationship with the roots of plants, providing several benefits to the host plants. The given options pertain to the advantages associated with mycorrhizal associations:
Resist Drought and Increase Absorptive Area:
- Mycorrhizal fungi help plants resist drought conditions. They form a network of hyphae that extends into the soil, increasing the absorptive area of the plant roots. This enhanced absorptive area allows plants to access water more efficiently, contributing to drought resistance.
Tolerate Extremes of pH:
- Mycorrhizal associations can enhance a plant’s ability to tolerate extremes of pH in the soil. The mycorrhizal network aids in nutrient uptake and can contribute to the plant’s ability to thrive in soils with varying pH levels.
Resist Disease Infestation:
- While mycorrhizal associations primarily focus on improving nutrient and water uptake, there is evidence to suggest that mycorrhizal fungi can indirectly contribute to plant defense mechanisms. By enhancing the overall health and stress tolerance of plants, mycorrhizae may play a role in reducing susceptibility to certain diseases.
Q.6) In the context of the developments in Bioinformatics, the term ‘transcriptome”, sometimes seen in the news, refers to (2016)
(a) a range of enzymes used in genome editing
(b) the full range of mRNA molecules expressed by an organism
(c) the description of the mechanism of gene expression
(d) a mechanism of genetic mutations taking place in cells
ANSWER: B
Explanation:
- The term ‘transcriptome’ refers to the full range of messenger RNA (mRNA) molecules that are produced or expressed by the cells of an organism. It represents the entire set of transcripts that are generated as a result of transcription, the process where information from DNA is used to synthesize RNA molecules.
- In simpler terms, the transcriptome provides a snapshot of all the active genes and the specific RNA molecules they produce at a given moment in a particular cell or tissue. It is crucial for understanding gene expression patterns, which play a vital role in various biological processes, development, and responses to environmental changes. Analyzing the transcriptome helps researchers gain insights into how genes are turned on or off in different conditions, providing valuable information about the functioning of cells and organisms.
Q.7) What is the application of Somatic Cell Nuclear Transfer Technology? (2017)
(a) Production of bio larvicides
(b) Manufacture of biodegradable plastics
(c) Reproductive cloning of animals
(d) Production of organisms free of diseases
ANSWER: C
Explanation:
- Somatic Cell Nuclear Transfer (SCNT) is a sophisticated laboratory technique employed for cloning organisms by transferring the nucleus of a somatic cell into an enucleated egg cell. The process starts with the isolation of a somatic cell containing the complete genetic information of the donor organism. Subsequently, an egg cell, obtained from a female donor, undergoes a process to remove its nucleus, leaving it enucleated. The somatic cell and the enucleated egg are then fused, creating a reconstructed egg that possesses the genetic material of the somatic cell.
- This reconstructed egg is activated to stimulate cell division and initiate the developmental process, often involving chemical or electrical stimulation. The activated egg, now containing the genetic material of the somatic cell, can either be implanted into a surrogate mother or cultured in a laboratory for further development. The primary application of SCNT lies in reproductive cloning, enabling the production of genetically identical animals. While it holds potential benefits in agriculture, medicine, and conservation, ethical considerations and ongoing research aim to address concerns related to efficiency and the health of cloned organisms.
Q.8) With reference to the Genetically Modified mustard (GM mustard) developed in India. consider the following statements: (2018)
- GM mustard has the genes of a soil bacterium that give the plant the property of pest-resistance to a wide variety of pests.
- GM mustard has the genes that allow plant cross-pollination und the plant hybridization.
- GM mustard has been developed jointly by the IARI and Punjab Agricultural University
Which of the statements given above is/are correct?
(a) 1 and 3 only
(b) 2 only
(c) 2 and 3 only
(d) 1, 2 and 3
ANSWER: B
Explanation:
- Statement 1 is incorrect because GM mustard has been developed with the barnase-barstar gene system, not genes from a soil bacterium. The barnase-barstar system imparts male sterility to the plant, preventing self-pollination and facilitating the production of hybrid seeds.
- Statement 2 is correct. GM mustard allows for cross-pollination and hybridization. The male sterility introduced by the barnase-barstar system promotes outcrossing, which is essential for hybrid seed production.
- Statement 3 is incorrect. GM mustard was developed by the Centre for Genetic Manipulation of Crop Plants (CGMCP) at the University of Delhi South Campus, not by the IARI (Indian Agricultural Research Institute) and Punjab Agricultural University.
Q.9) With reference to the recent developments in science, which one of the following statements is not correct? (2019)
(a) Functional chromosomes can be created by joining segments of DNA taken from cells of different species.
(b) Pieces of artificial functional DNA can be created in laboratories.
(c) A piece of DNA taken out from an animal cell can be made to replicate outside a living cell in a laboratory.
(d) Cells taken out from plants and animals can be made to undergo cell division in laboratory petri dishes.
ANSWER: A
Explanation:
- Creating functional chromosomes by joining segments of DNA from cells of different species involves several complex challenges and considerations.
Genetic Engineering Techniques:
- Genetic engineering allows scientists to manipulate DNA at the molecular level. Techniques such as recombinant DNA technology involve cutting and splicing DNA from different sources.
- Specific genes of interest can be inserted into the DNA of an organism, enabling the expression of desired traits.
Chromosome Structure and Function:
- Chromosomes are complex structures composed of DNA and proteins. They carry genetic information and are crucial for the regulation of cellular processes.
- Each species has a unique set of chromosomes, and the structure, organization, and regulation of these chromosomes are highly specific to that species.
Cross-Species Challenges:
- Creating functional chromosomes by combining segments from different species is challenging due to the intricate regulatory mechanisms.
- The regulatory elements, such as promoters and enhancers, that control gene expression are specific to each species. Combining DNA from different species may result in incompatible regulatory interactions.
Species-Specific Factors:
- Chromosomes carry not only genes but also non-coding regions that play critical roles in regulating gene expression. These non-coding regions are often species-specific.
- Differences in epigenetic modifications, which affect gene activity without altering the DNA sequence, can also pose challenges when combining DNA from different species.
Functional Integration:
- Creating a functional chromosome involves ensuring that the inserted DNA integrates correctly into the host organism’s genome.
- The host organism must be capable of recognizing and utilizing the foreign DNA for normal cellular processes.
Ethical and Safety Considerations:
- Genetic modifications involving the creation of chromosomes from different species raise ethical concerns.
- Safety considerations, such as unintended consequences or ecological impacts, need to be thoroughly evaluated before implementing such techniques.
Q.10) RNA interference (RNAi)’ technology has gained popularity in the last few years. Why? (2019)
- It is used in developing gene silencing therapies.
- It can be used in developing therapies for the treatment of cancer.
- It can be used to develop hormone replacement therapies.
- It can be used to produce crop plants that are resistant to viral pathogens.
Select the correct answer using the code given below.
(a) 1, 2 and 4
(b) 2 and 3
(c) 1 and 3
(d) 1 and 4 only
ANSWER: A
Explanation:
Used in developing gene silencing therapies:
- RNA interference (RNAi) is a natural cellular process that involves the silencing of gene expression. Researchers have harnessed this process to develop gene silencing therapies, where specific genes associated with diseases can be targeted and silenced.
Used in developing therapies for the treatment of cancer:
- RNAi technology has shown promise in cancer therapy by targeting and silencing genes involved in cancer cell growth. It can be used to develop targeted therapies to treat various types of cancer.
Not directly related to hormone replacement therapies:
- RNAi technology is not typically used for hormone replacement therapies. It is more commonly associated with regulating gene expression at the level of RNA.
Used to produce crop plants resistant to viral pathogens:
- RNAi technology has been explored for developing genetically modified (GM) crops that are resistant to viral pathogens. By introducing RNA molecules targeting specific viral genes, plants can be engineered to resist viral infections.
Q.11) What is Cas9 protein that is often mentioned in news? (2019)
(a) A molecular scissors used in targeted gene editing
(b) A biosensor used in the accurate detection of pathogens in patients
(c) A gene that makes plants pest- resistant
(d) An herbicidal substance synthesized in genetically modified crops
ANSWER: A
Explanation:
- Cas9 is a key component of the CRISPR-Cas9 gene-editing technology, acting like a pair of molecular scissors that can precisely cut DNA at specific locations. This revolutionary technology allows scientists to modify genes with high precision, offering potential applications in various fields, including medicine, agriculture, and biotechnology.
Q.12) Consider the following statements: (2020)
- Genetic changes can be introduced in the cells that produce eggs or sperms of a prospective parent.
- A person’s genome can be edited before birth at the early embryonic stage.
- Human induced pluripotent stem cells can be injected into the embryo of a pig.
Which of the statements given above is/are correct?
(a) 1 only
(b) 2 and 3 only
(c) 2 only
(d) 1, 2 and 3
ANSWER: D
Explanation:
Genetic changes can be introduced in the cells that produce eggs or sperms of a prospective parent:
- This statement is correct. Genetic changes can be introduced into germ cells (sperm and egg cells), and this is known as germline editing. It has ethical implications and requires careful consideration.
A person’s genome can be edited before birth at the early embryonic stage:
- This statement is correct. Editing the genome at the early embryonic stage is a possibility, and it is part of the broader field of genetic engineering.
Human induced pluripotent stem cells can be injected into the embryo of a pig:
- This statement is correct. Scientists have explored the possibility of injecting human induced pluripotent stem cells into animal embryos for various purposes, including the study of disease mechanisms and potential organ transplantation in the future.
Q.13) In the context of recent advances in human reproductive technology, “Pronuclear Transfer” is used for (2020)
(a) fertilization of egg in vitro by the donor sperm
(b) genetic modification of sperm producing cells
(c) development of stem cells into functional embryos
(d) prevention of mitochondrial diseases in offspring
ANSWER: D
Explanation:
- Pronuclear transfer is a technique used in the context of mitochondrial replacement therapy (MRT).
- It involves transferring the nucleus of a fertilized egg (zygote) from a woman with mitochondrial disease to a healthy donor egg with normal mitochondria.
- The goal is to prevent the transmission of mitochondrial diseases from mother to child.
- Mitochondrial diseases are caused by defects in the mitochondria, which are inherited maternally.
Q.14) Bollgard I and Bollgard II technologies are mentioned in the context of (2021)
(a) clonal propagation of crop plants
(b) developing genetically modified crop plants
(c) production substances of plant growth
(d) production of biofertilizers
ANSWER: B
Explanation:
- Bollgard I and Bollgard II are technologies related to genetically modified (GM) crop plants, specifically in the context of cotton. These technologies involve the incorporation of genes from the bacterium Bacillus thuringiensis (Bt) into cotton plants.
Bollgard I Technology:
- In Bollgard I, the cotton plants are genetically modified to express a specific Bt toxin (Cry1Ac). This toxin is toxic to certain insect pests, especially bollworms (larvae of certain moths), which are known to damage cotton crops.
- The Bt toxin is produced within the plant tissues, particularly in the cotton bolls where the seeds are located. When bollworm larvae feed on the plant, they ingest the toxin, leading to their death.
Bollgard II Technology:
- Bollgard II is an advanced version that incorporates additional Bt toxins for broader protection against insect pests.
- In Bollgard II, along with Cry1Ac, another Bt toxin (Cry2Ab2) is expressed. This dual-toxin approach is designed to provide enhanced resistance against a wider spectrum of insect pests, including those that may have developed resistance to Cry1Ac.
Q.15) ‘Microsatellite DNA’ is used in the case of which one of the following? (2023)
(a) Studying the evolutionary relationships among various species of fauna
(b) Stimulating ‘stem cells’ to transform into diverse functional tissues
(c) Promoting clonal propagation of horticultural plants
(d) Assessing the efficacy of drugs by conducting series of drug trials in a population
Answer: A
Q.16) Consider the following statements : (2022)
DNA Barcoding can be a tool to:
- assess the age of a plant or animal.
- distinguish among species that look alike.
- identify undesirable animal or plant materials in processed foods.
Which of the statements given above is/are correct?
(a) 1 only
(b) 3 only
(c) 1 and 2
(d) 2 and 3
Answer: D
