UPSC 1996 Science and Technology Questions with Answers

Explanation

The physico-chemical characteristics of water in water sources are primarily affected by effluents discharged from various sources, including industries, sewage, and agricultural runoff. Effluents introduce pollutants like organic matter, chemicals, heavy metals, and nutrients into water bodies, leading to significant changes in water quality. How Effluents cause Changes:

Chemical Changes: Effluents can alter the pH, increase the concentration of harmful chemicals, and introduce toxic substances. Nutrient Loading: Excessive nutrients (like nitrates and phosphates) from effluents can cause eutrophication, leading to algal blooms. Dissolved Oxygen Levels: Organic pollutants increase the Biological Oxygen Demand (BOD), reducing dissolved oxygen levels and harming aquatic life. Turbidity and Color: Effluents can increase turbidity, reduce light penetration, and alter the color of the water.

Explanation

Living organisms require a variety of elements for various physiological functions. Among these, certain elements are required in major quantities (also known as macronutrients). The elements potassium (K), sodium (Na), magnesium (Mg), and calcium (Ca) are macronutrients required in relatively large amounts by living organisms:

Potassium (K) is vital for cell function, maintaining osmotic balance, and nerve transmission. Sodium (Na) is important for maintaining osmotic pressure and fluid balance, as well for nerve function. Magnesium (Mg) is essential for photosynthesis in plants, enzyme function, and the structural component of bones in animals. Calcium (Ca) is crucial for bone and teeth formation, muscle contraction, blood clotting, and nerve function.

Explanation

Seedless tomatoes can be produced through a process called parthenocarpy where fruits develop without fertilization and thus contain no seeds. This is achieved by spraying hormones like gibberellins or auxins on the flowers of the tomato plants. These hormones promote fruit development without the need for fertilization leading to seedless fruits.

Explanation

A is matched with 2: Photosynthesis occurs in the chloroplasts where light energy is converted into chemical energy forming glucose and oxygen. B is matched with 1: Mineral uptake happens at the plasma membrane, where ions and nutrients are absorbed into the cell. C is matched with 3: Respiration takes place in the mitochondria, where glucose is broken down to release energy in the form of ATP. D is matched with 4: Protein synthesis occurs at the ribosomes where mRNA is translated into proteins.

Explanation

The potato is a modified stem known as a tuber. It is an underground stem that stores food and is capable of producing new shoots (vegetative reproduction). The "eyes" on the surface of a potato are actually buds from which new potato plants can grow. The sweet potato is also a modified root (specifically, a storage root) and not a stem. The coconut is a fruit and contains a seed, not a modified stem. Its outer husk is a part of the fruit, not a stem modification.

Explanation

Plastic surgery is the earliest medical advancement among the options listed. It dates back to ancient India, where Sushruta, known as the “Father of Surgery,” described advanced reconstructive surgical techniques in the 6th century BCE. He performed reconstructive procedures such as rhinoplasty (nose reconstruction). These procedures were significantly ahead of their time and predates other medical milestones by centuries.

Explanation

As per the WHO reports around 1996, Tuberculosis (TB) which is caused by Mycobacterium tuberculosis was responsible for the highest number of deaths globally. It primarily affects the lungs and is prevalent in developing countries due to poverty, overcrowded living conditions, and limited access to healthcare. TB has remained a significant global health burden despite being curable and preventable. However, currently Heart diseases are the largest reason behind human mortality.

Explanation

Xerophthalmia, caused by Vitamin A deficiency, is a critical public health issue in India. It primarily affects children and can lead to dryness of the conjunctiva and cornea, eventually resulting in blindness if left untreated. Addressing this condition through improved dietary intake and supplementation programs is a top priority for reducing malnutrition and its consequences in India.

Explanation

Option (b) is correct:

A is matched with 2: Carotene, specifically beta-carotene, is a provitamin A carotenoid found in plant foods. It is converted into vitamin A (retinol) in the human body which plays a crucial role in vision, immune function, and skin health. B is matched with 1: Enzymes are biological catalysts that speed up chemical reactions in the body. Pepsin is a digestive enzyme produced in the stomach that breaks down proteins into smaller peptides. C is matched with 4: Hormones are signaling molecules produced by glands that regulate physiological processes. Progesterone is a steroid hormone involved in the menstrual cycle, pregnancy, and embryogenesis. D is matched with 3: Proteins are large biomolecules made of amino acids that perform a variety of functions in the body. Keratin is a structural protein found in hair, nails, and the outer layer of skin.

Explanation

Diabetes mellitus is characterized by higher blood sugar levels (hyperglycemia) due to either insufficient insulin production or reduced insulin sensitivity. Type 1 diabetes (previously known as insulin-dependent, juvenile or childhood-onset) is characterized by deficient insulin production and requires daily administration of insulin. Type 2 diabetes affects how your body uses sugar (glucose) for energy. It stops the body from using insulin properly, which can lead to high levels of blood sugar if not treated.