Biotechnology & Genetic Engineering

Statement 1 is correct: The Guchhi mushroom is a species of fungus in the Morchellaceae family of the Ascomycota. It exhibits a pale yellow colouration with large pits and ridges on the surface of the cap, which is elevated on a large white stem. Statement 2 is correct: This mushroom is cultivated in the foothills of the Himalayas, specifically in regions such as Himachal Pradesh, Uttaranchal, and Jammu and Kashmir. Statement 3 is incorrect: These mushrooms cannot be cultivated on a commercial scale and instead grow naturally in conifer forests across various temperature regions. It takes months for villagers to gather sufficient quantities of these mushrooms, dry them, and transport them to the market.

Statement 1 is incorrect: Covishield, produced by the Serum Institute of India, is a viral vector vaccine. It uses a weakened chimpanzee adenovirus vector to carry genetic material from the SARS-CoV-2 virus into human cells. Statement 2 is correct: Sputnik V is a vector-based vaccine, similar to Covishield. It uses two different human adenovirus vectors to deliver genetic material coding for SARS-CoV-2 spike proteins. Statement 3 is correct: COVAXIN, developed by Bharat Biotech, is an inactivated virus vaccine. This means the SARS-CoV-2 virus used in the vaccine is inactivated (killed) so it cannot cause infection, but it still triggers an immune response.

Statement 1 is correct. Probiotics can be made from both bacteria and yeast. Some common probiotic strains include bacteria like Lactobacillus and Bifidobacterium, and yeasts like Saccharomyces boulardii. Statement 2 is incorrect. The organisms in probiotics are naturally found in the human gut. We have a complex gut microbiome with trillions of bacteria and other microbes, some of which are beneficial. Probiotics are supposed to introduce specific strains of these beneficial microbes to improve gut health. Statement 3 is correct. Probiotics might help with lactose digestion, but it depends. Lactose intolerance is caused by a lack of the enzyme lactase, which breaks down lactose (milk sugar) in the gut. Some probiotic strains might produce lactase, potentially aiding digestion in lactose-intolerant individuals.

Bollgard I and Bollgard II technologies are mentioned in the context of developing genetically modified (GM) cotton plants resistant to insect pests. * Bollgard I: This was India's first commercially approved GM crop technology introduced in 2002. It incorporates a single gene (Cry1Ac) from the bacterium Bacillus thuringiensis (Bt) into cotton plants. This Bt gene produces an insecticidal protein that targets and kills certain insect pests, particularly the American Bollworm (Helicoverpa armigera). * Bollgard II: This is a more advanced technology introduced in mid-2006. It incorporates two genes (Cry1Ac and Cry2Ab) from Bt into cotton. This provides broader resistance against a wider spectrum of insect pests, including lepidopteran caterpillars like the Spodoptera species, in addition to the American Bollworm.

Statement 1 is correct. Genetic engineering in vaccine development works by modifying the genetic material of viruses, bacteria, or lab-grown cells to produce specific proteins that trigger an immune response. Scientists first identify a target protein from a pathogen that can help the immune system recognize and fight it. They then insert the gene coding for this protein into a harmless virus, bacterial cell, or a lab-grown system, which acts as a factory to produce large amounts of the antigen. The antigen is then purified and combined with other ingredients to create the final vaccine. When injected, the vaccine stimulates the immune system to recognize and attack the actual pathogen if encountered in the future. This approach is used in various vaccines, including mRNA vaccines like those for COVID-19 and recombinant protein vaccines like the Hepatitis B vaccine. Statement 2 is correct. Bacteria and viruses are commonly used as vectors in recombinant vector vaccines. These vectors serve as delivery vehicles to transport genetic material from the target pathogen into host cells, where the antigens are produced. The host immune system then recognizes these antigens and mounts an immune response. | Vector Type | Examples of Vectors |
|------------------|--------------------------------------------------------------------------------------------------------|
| Viral Vectors | Adenovirus, Vaccinia Virus (MVA), Vesicular Stomatitis Virus (VSV), Measles Virus, Influenza Virus |
| Bacterial Vectors| Salmonella typhimurium, Listeria monocytogenes, Mycobacterium bovis (BCG) |
| Fungal Vectors | Saccharomyces cerevisiae (Yeast) |
| Protozoan Vectors| Leishmania donovani, Trypanosoma cruzi |

The Lemongrass plant is known to be an excellent mosquito repellant. According to a study conducted in 2011, around 95% of mosquitos from a specific range of species were either killed or completely repelled due to the intense odour of lemongrass oil. Commonly known as Citronella oil, the impact of the essential oil from Lemongrass is known to last for around two and a half hours. For some species of mosquitos, it is even more.

Statement 1 is correct. Mitochondrial replacement therapy (MRT) is a reproductive technique used to prevent the transmission of mitochondrial diseases from mother to child. It involves replacing defective mitochondria in an egg or embryo with healthy mitochondria from a donor. MRT can be performed either before or after in vitro fertilization to ensure that the resulting embryo does not inherit mitochondrial diseases. Statement 2 is correct. Mitochondrial DNA (mtDNA), which is responsible for encoding genes essential for mitochondrial function, is inherited exclusively from the mother. Therefore, mitochondrial diseases caused by mutations in mtDNA are passed down maternally, and a child cannot inherit mitochondrial diseases from the father. Therefore, both statements are correct.

Statement 1 is correct: The bud chip method involves raising sugarcane settlings in a nursery before transplanting them into the main field. This method reduces seed material requirements by using only the bud instead of the entire sett, leading to cost savings and better efficiency. Statement 2 is incorrect: Multi-budded setts generally have a higher germination percentage than single-budded setts. Single-budded setts may face more difficulty in germination compared to setts with multiple buds, which provide better shoot emergence. Statement 3 is incorrect: Under adverse weather conditions, large setts have better survival rates because they store more nutrients and moisture. Single-budded setts are more vulnerable to unfavorable conditions and may have lower survival rates. Statement 4 is correct: Tissue culture techniques are successfully used for sugarcane cultivation. Settlings prepared from tissue culture help in producing disease-free, high-yielding plants and allow rapid multiplication of quality planting material. Hence, option C is the correct answer.

Pronuclear transfer, in the context of human reproductive technology, is used for preventing mitochondrial diseases in offspring. Here's why - Mitochondria: These are cellular organelles with their own DNA (mitochondrial DNA or mtDNA) separate from nuclear DNA. Mutations in mtDNA can cause various inherited mitochondrial diseases that can affect organs like muscles, nerves, and the brain. - Pronuclear Transfer Technique: This technique involves the fertilization of an egg with sperm. Then, the pronuclei (nuclei before fusion) from both sperm and egg are removed. These pronuclei are then injected into a donor egg that has had its own pronuclei removed, but has healthy mtDNA.

Statement 1 is correct. Plant cells have rigid cell walls made of cellulose, a complex carbohydrate, which animal cells lack. Animal cells rely on a plasma membrane for structure and protection. Statement 2 is incorrect. Both plant and animal cells have a plasma membrane, a phospholipid bilayer that controls what enters and leaves the cell. It's a fundamental component for all cells. Statement 3 is correct. Mature plant cells typically have a single, large central vacuole that stores water, nutrients, and waste products. Animal cells can have vacuoles, but they are usually smaller and more numerous.