Miscellaneous: UPSC Previous Year Questions (Science and Technology)

Explanation

The Fractional Orbital Bombardment System (FOBS) is a missile technology designed to place a nuclear warhead into a partial Earth orbit before deorbiting to strike a target. Unlike intercontinental ballistic missiles (ICBMs), FOBS takes an unpredictable orbital path, bypassing traditional radar systems and potentially striking from unexpected directions, such as via the South Pole. Originally developed by the Soviet Union in the 1960s, FOBS was tested with the R-36ORB missile but later abandoned under arms control treaties like SALT II and the Outer Space Treaty. Recent reports indicate renewed interest, with countries like China reportedly testing FOBS integrated with hypersonic glide vehicles. Its capability to evade missile defenses has raised global security concerns and spurred advancements in countermeasures. ICBM Radar Beam Launch site FOBS FOBS Apogee ~150 km ~1200 km Target Early-warning Radar Fig: Fractional Orbital Bombardment System (FOBS)

Explanation

A biofilm is a collection of microbial cells that are encased in a polysaccharide-based matrix and are permanently attached to a surface (i.e., cannot be removed by gentle rinsing). Microorganisms that form biofilms include bacteria, fungi, and protists. Noncellular materials such as mineral crystals, corrosion particles, clay or silt particles, or blood components, depending on the environment in which the biofilm has developed, may also be found in the biofilm matrix.

Statement 1 is correct: Biofilms may form on a wide variety of surfaces, including living tissues, food and food processing surfaces, indwelling medical devices (devices in the body like catheters, heart valves), human and animal tissue, industrial or potable water system piping, or natural aquatic systems.

Statement 2 is correct: Biofilms are a significant concern in the food industry, forming on surfaces such as cutting boards, conveyor belts, and food packaging equipment. Contaminated biofilms can lead to foodborne illnesses caused by pathogens like Listeria monocytogenes, Salmonella, and Escherichia coli.

Statement 3 is correct: Microorganisms in biofilms are significantly more resistant to antibiotics compared to planktonic (free-floating) cells because:

The EPS (extracellular polymeric substance) matrix acts as a barrier, limiting antibiotic penetration. Cells within biofilms have reduced metabolic activity, making them less susceptible to antibiotics targeting active processes. Some bacteria within biofilms can exchange antibiotic resistance genes via horizontal gene transfer. This resistance complicates treatment, especially in chronic infections such as cystic fibrosis, where Pseudomonas aeruginosa biofilms are common.