Biotechnology: UPSC Previous Year Questions (Science and Technology)

Explanation

Mycorrhizae is a symbiotic association between a fungus and a plant. The term ‘mycorrhiza’ refers to the role of the fungus in the plant’s rhizosphere, its root system. Mycorrhiza plays important roles in plant nutrition, soil biology and soil chemistry.

Statement 1 is correct: Trees host mycorrhizal fungus in their roots so they can absorb nutrients from the ground and resist the drought condition. These fungi exchange the carbon from the tree for vital nutrients including nitrogen, phosphate, and potassium from the soil.

Statement 2 is correct: Mycorrhizal plants can withstand unfavourable soil conditions, high pH levels, droughts, and poisonous heavy metals.

Statement 3 is correct: Mycorrhizae are symbiotic relationships between plant roots and specific soil fungi that are important for the ecosystem’s nutrient cycling and that help shield plants from environmental and cultural stress. Additionally, mycorrhizal fungi’s synthesis of oxalic acid contributes to disease suppression.

Explanation

Recombinant DNA technology entails changing genetic material outside of an organism to produce living organisms or their products with improved and desired traits. Using the appropriate vectors, this approach entails inserting DNA fragments from a number of sources that have the desired gene sequence. Manipulation in an organism’s genome is carried out either through the introduction of one or several new genes and regulatory elements or by decreasing or blocking the expression of endogenous genes through recombining genes and elements. Recombinant DNA technology, also known as genetic engineering, enables the transfer of genes across different species, including:

Across different species of plants: Genes can be transferred between various plant species to introduce desirable traits. From animals to plants: Animal genes can be introduced into plants to confer new characteristics. From microorganisms to higher organisms: Microbial genes can be inserted into higher organisms, such as plants or animals, to impart beneficial properties.

Explanation

Brinjal is a resilient crop that thrives even in drought-prone areas and is cultivated throughout most of the country. In India, Bt brinjal was the first food crop to undergo evaluation for potential commercial release.

Statement 1 is incorrect: A gene called cry1Ac from the soil bacterium Bacillus thuringiensis(and not fungus) was inserted into the brinjal to develop Bt Brinjal. This brinjal has been genetically modified to withstand insects like the Brinjal Fruit and Shoot Borer (Leucinodes orbonalis).

Statement 2 is incorrect: Farmers will be free to save and sow as many seeds from Bt Brinjal open-pollinated cultivars as they like. They are not terminator seeds.

Statement 3 is correct: Public resistance to Bt brinjal in India was driven by fears of allergic reactions, toxicity and long-term health effects.

Statement 4 is correct: Environmentalists feared that introducing Bt brinjal could negatively impact biodiversity. The primary concern was the potential for cross-pollination with native brinjal varieties, which could lead to genetic contamination and loss of indigenous strains.

Explanation

Genetic engineering is the direct manipulation of an organism’s genes using biotechnology techniques, allowing for the alteration of its DNA.

Statement 1 is correct: GE crops have been engineered to withstand drought conditions which allows them to maintain productivity under water scarcity. For instance, genetically modified wheat with enhanced drought tolerance has been developed.

Statement 2 is correct: Biofortification through genetic engineering has led to crops with enhanced nutritional profiles. Example: Golden Rice has been engineered to produce beta-carotene, a precursor of vitamin A.

Statement 3 is incorrect: Genetic engineering for space-specific traits (like enhanced photosynthesis in low light or microgravity) is not a major application of genetically engineered plants presently. Research is ongoing into growing plants in space (Ex-NASA’s experiments with growing lettuce on the International Space Station) but these efforts primarily focus on optimizing growth conditions rather than genetically engineering plants.

Statement 4 is correct: Genetic engineering has been used to delay ripening and spoilage in fruits and vegetables. For example: Flavr Savr Tomato is the first commercially available genetically engineered crops, designed to ripen more slowly and extend shelf life.

Explanation

DNA Sequencing means determining the order of the four chemical building blocks - called "bases" - that make up the DNA molecule. This sequence informs scientists the kind of genetic information that is carried in a particular DNA segment.

Statement 1 is correct: Pedigree analysis is the examination of a particular trait that is inherited from generation to generation. It helps in understanding the inheritance pattern of that trait and determining whether it is dominant or recessive. A thorough pedigree analysis using pedigree files received via DNA sequencing from the relevant breed organisations will certainly help in interpreting the pattern of inheritance of a livestock.

Statement 2 is correct: Mapping genes allows researchers to identify genetic variations associated with diseases. This understanding facilitates the development of targeted therapies and personalized medicine approaches.

Statement 3 is incorrect: Knowledge of gene positions enables the identification of genes responsible for disease resistance. This information can be utilized to breed or genetically engineer animals that are more resilient to specific diseases. However UPSC has not recognised it as completely true as if this application of DNA sequencing is still under development.

Explanation

CyberKnife is an advanced radiosurgery technology that allows real-time tracking and adjustment of radiation beams, ensuring precise targeting of tumors while minimizing damage to surrounding healthy tissues. These features make CyberKnife highly effective for treating tumors in sensitive areas such as the brain, spine, and lungs. Options (a), (b) and (c) are correct: CyberKnife is a non-invasive robotic radiosurgery system used to treat cancerous and non-cancerous tumors. It is a robotic image-guided system, capable of delivering extremely precise doses of radiation with sub-millimeter accuracy.

Option (d) is incorrect: CyberKnife is not designed to map the spread of tumors in the body. Its role is strictly limited to treating targeted tumor regions. Imaging techniques such as PET scans, CT scans, and MRIs are used to identify and map tumor spread, whereas CyberKnife focuses solely on delivering radiation therapy with exceptional precision.

Explanation

Golden rice is a genetically modified variety of rice specifically engineered to address vitamin A deficiency. The grains of Golden rice are biofortified with beta-carotene, a precursor of vitamin A (pro-vitamin A). When consumed, beta-carotene is converted into vitamin A in the human body, making golden rice an important dietary intervention to combat vitamin A deficiency, particularly in developing countries where this deficiency is prevalent and can lead to serious health issues like blindness.

Explanation

The Ministry of Rural Development was designated as the nodal ministry for implementing the National Biodiesel Mission during its initial phases. The mission focused on cultivating Jatropha curcas, a non-edible oilseed crop, on wastelands to produce biodiesel. Jatropha is a plant of Latin American origin, which is now widespread throughout arid and semi-arid tropical regions of the world. This initiative aimed to achieve energy security, promote rural development, and provide an alternative source of livelihood for farmers in marginal and degraded lands.

Explanation

Enzyme-linked immunosorbent assay (ELISA) is a laboratory technique that detects and measures the amount of specific substances in a solution.

Statement 1 is incorrect: The ELISA (Enzyme-Linked Immunosorbent Assay) test is primarily used to detect the presence of antibodies or antigens in the blood, and it is widely employed for diagnosing infections such as HIV, rather than cancer. It is not the first or basic test for cancer detection. Cancer is typically diagnosed using imaging techniques (e.g., MRI, CT scans), biopsies, or specific blood marker tests.

Statement 2 is incorrect: The Rh factor, also known as the Rhesus factor, is a protein that can be present on the surface of red blood cells. Individuals with this protein are classified as Rh-positive (Rh+), while those without it are Rh-negative (Rh-). Globally, the distribution of Rh factor is not evenly split. Approximately 94% of the world’s population is Rh-positive, and only about 6% is Rh-negative. This distribution varies among different populations and regions.

Explanation

Dr. V. Mohan Reddy is renowned for performing a successful open-heart procedure called the arterial switch operation on an infant. This operation is a complex cardiac surgery used to correct transposition of the great arteries, a congenital heart defect where the major arteries are reversed. This breakthrough surgery provided new hope for treating congenital heart diseases in infants and gained recognition as a landmark achievement in pediatric cardiac surgery.