Health: UPSC Previous Year Questions (Science and Technology)

Explanation

About the Wolbachia Method Wolbachia is a type of bacterium, that can be introduced into mosquitoes to diminish their capacity for transmitting diseases. Fig: Wolbachia method Wolbachia method is used to control the population of mosquitoes and thus helps in controlling viral diseases such as zika, dengue, and chikungunya spread by the mosquitoes. In this method, the male Aedes Aegypti mosquitoes with Wolbachia mate with wild female mosquitoes that do not have Wolbachia, the eggs will not hatch and thus leads to sterilisation.

Explanation

Probiotics are live microorganisms that are intended to have health benefits when consumed or applied to the body.

Statement 1 is correct: Probiotics can be composed of bacteria, yeast, or both. The most common types of bacteria used as probiotics are Lactobacillus and Bifidobacterium, while Saccharomyces boulardii is an example of a yeast that is sometimes used as a probiotic.

Statement 2 is incorrect: Probiotics contain microorganisms that are similar to or the same as those naturally present in our bodies, especially in the digestive tract. Our gut microbiota consists of many types of bacteria, some of which are also found in probiotic products. These probiotics are often called "good" or "friendly" bacteria because they support gut health.

Statement 3 is correct: Some probiotic bacteria, like Lactobacillus, produce an enzyme called lactase, which helps in the digestion of milk sugar (lactose). Lactase breaks down lactose into simpler sugars, making it easier for the body to absorb. This is especially helpful for people who are lactose intolerant and have difficulty digesting dairy products.

Explanation

B cells and T cells are integral components of the human immune system, each playing distinct roles in protecting the body from diseases caused by pathogens. B cells are primarily responsible for humoral immunity. They produce antibodies that specifically target and neutralize pathogens such as bacteria and viruses. T cells play a crucial role in cell-mediated immunity, not by producing antibodies but by carrying out essential immune functions. Helper T cells activate B cells to stimulate other immune cells to enhance the body’s defense. Cytotoxic T cells target and destroy infected or cancerous cells, eliminating harmful threats. Regulatory T cells help maintain immune balance by preventing excessive or inappropriate immune responses.

Explanation

Mitochondrial diseases are a group of genetic disorders caused by dysfunction in the mitochondria, the cell’s energy-producing structures.

Statement 1 is correct: Mitochondrial Replacement Therapy (MRT) is an advanced reproductive technique designed to prevent the transmission of mitochondrial diseases from mother to child. MRT involves replacing defective mitochondria in an egg or embryo with healthy mitochondria from a donor. This can be achieved through methods such as:

Spindle Transfer: Performed before fertilization, where the nuclear DNA from the mother’s egg is transferred to a donor egg with healthy mitochondria, followed by fertilization. Pronuclear Transfer: Conducted after fertilization, where the pronuclei (genetic material) from a fertilized egg are transferred into a donor zygote that has healthy mitochondria. These techniques aim to ensure that the resulting child inherits healthy mitochondria, thereby preventing mitochondrial diseases.

Statement 2 is correct: A child inherits mitochondrial diseases entirely from the mother and not from the father. Mitochondria are unique organelles within cells that have their own DNA, known as mitochondrial DNA (mtDNA). Unlike nuclear DNA, which is inherited from both parents, mtDNA is typically inherited exclusively from the mother. This is because the mitochondria in the sperm are usually destroyed or degraded after fertilization, and thus do not contribute to the embryo’s mitochondrial pool. Consequently, if a mother has a mitochondrial disease (caused by mutations in her mtDNA), there is a risk that she can pass it on to her children, while fathers do not pass on mtDNA to their offspring, and thus do not transmit mitochondrial diseases.

Explanation

ACE2 (Angiotensin Converting Enzyme 2) is a protein on the surface of many cell types and tissues, including the lungs, heart, blood vessels, kidneys, liver, and gastrointestinal tract. It serves as the entry point for certain coronaviruses, notably SARS-CoV-2, the virus responsible for COVID-19. The virus’s spike protein binds to the ACE2 receptor, facilitating its entry into host cells and leading to infection.

Explanation

Gene therapy is the ability to improve genes through the correction of misplaced (mutated) genes or site-specific alterations with therapeutic treatment as the target. A gene abnormality that has been identified in a child or embryo can be corrected using a variety of techniques known as gene therapy. In this instance, genes are injected to treat an illness into a person’s cells and tissues.

Statement 1 is correct: Genetic modifications can be made to germ cells (sperm or eggs) of prospective parents. Techniques like CRISPR/Cas9 allow for precise editing of DNA in these cells, potentially preventing the transmission of genetic diseases to offspring.

Statement 2 is correct: Genome editing technologies, such as CRISPR/Cas9, allow scientists to precisely modify DNA at the early embryonic stage to correct genetic defects. This approach, called germline editing, involves altering the genome of an embryo at its earliest stage of development, ensuring that all cells in the resulting organism carry the change. These genetic modifications are heritable, meaning they can be passed down to future generations. While this technique offers the potential to prevent inherited genetic disorders, it also raises serious ethical concerns, such as the possibility of creating "designer babies" and safety challenges, including the risk of unintended genetic changes (off-target effects) that could cause unforeseen health issues.

Statement 3 is correct: Human induced pluripotent stem cells (iPSCs) have been experimentally integrated into pig embryos to create interspecies chimeras. This research aims to understand developmental biology and explore organ transplantation possibilities, such as growing human-compatible organs in animals.

Explanation

Statement 1 is correct: The Zika virus is primarily transmitted by the Aedes aegypti mosquito which is also the primary vector for dengue fever. This mosquito species thrives in tropical and subtropical regions, making it a common carrier for both diseases. The Aedes aegypti mosquito is well-adapted to urban environments and breeds in stagnant water, such as in containers, flower pots, and discarded tires.

Statement 2 is correct: Zika virus can be transmitted through sexual contact unlike other mosquito-borne diseases like dengue or chikungunya. The virus can remain in semen for an extended period even after symptoms have resolved. Zika virus infection during pregnancy can cause severe birth defects such as microcephaly.

Explanation

According to the Food Safety and Standards (Packaging and Labeling) Regulations, 2011, pre-packaged items in India must display key information, including:

Nutrition information List of ingredients (including additives) Vegetarian/Non-vegetarian label Date of manufacture and packing Best-before date Lot number, Code number, or Batch number The regulations mandate that foods containing allergens such as cereals containing gluten, nuts, soybeans, milk, and fish must declare the presence of these allergens on the label. However, the regulations do not require a specific medical recommendation regarding allergic reactions

Explanation

Muscle contraction is a complex physiological process regulated by nerve impulses and the interaction of muscle proteins actin and myosin. Key minerals involved in muscle contraction include: Calcium (Ca), Sodium (Na), Potassium (K), Magnesium (Mg).

Option 1 is correct: Calcium ions are essential for muscle contraction. They bind to regulatory proteins within muscle fibers, facilitating the interaction between actin and myosin, the proteins responsible for muscle contraction. Without adequate calcium, muscles cannot contract properly.

Option 2 is correct: Iron helps to support continued functioning of the muscle by supporting energy production in your muscle cells, so that muscle fibres always have the energy they need to contract properly. Also supports healthy circulation so that muscles can receive additional oxygen from the bloodstream and helps muscles store oxygen to power muscle contractions.

Option 3 is correct: Sodium is crucial for initiating and transmitting nerve impulses that lead to muscle contraction. It helps generate action potentials in nerve cells, which then stimulate muscle fibers to contract. Proper sodium levels are necessary for effective communication between the nervous system and muscles.

Explanation

Biopesticides are various biologically active natural substances that exist in nature and have inhibitory effects on crop diseases and insect pests. In general, the creation of biopesticide depends to a large extent on biological resources.

Option (d) is correct:

Three major classes of biopesticides are:

Class of Biopesticides Description Examples Microbial Pesticides Consist of microorganisms (bacteria, fungi, viruses, or protozoa) as active ingredients for pest control. These may be naturally occurring, dead or alive, or genetically engineered. Bacillus thuringiensis (Bt) - produces toxins harmful to specific insects. Fungal Biopesticides Some fungi act as biopesticides by infecting and killing pests. Entomopathogenic fungi target insects, while others combat plant pathogens. Entomopathogenic fungi - infect and kill insects. Plant-Incorporated-Protectants (PIPs) Pesticidal substances that plants produce from inserted genetic material. Genetically modified corn and cotton, Neem oil (Azadirachta indica) - possesses insecticidal properties.