Q. Consider the following statements : - Some microorganisms can grow in environments with temperature above the boiling point of water.
- Some microorganisms can grow in environments with temperature below the freezing point of water.
- Some microorganisms can grow in highly acidic environment with a pH below 3.
How many of the above statements are correct? (UPSC Prelims 2023)
Answer:
All three
Notes: The correct answer is
[C] All three. Microorganisms, particularly extremophiles, have evolved unique biochemical adaptations that allow them to survive and thrive in conditions previously thought to be uninhabitable.
- Statement 1 (Correct): Certain microorganisms, known as hyperthermophiles, can grow at temperatures exceeding 100°C (the boiling point of water). For example, Strain 121, a single-celled archaeon, was discovered at hydrothermal vents in the Pacific Ocean and is capable of doubling its population at 121°C.
- Statement 2 (Correct): Psychrophiles (cold-loving organisms) are capable of growth at temperatures below the freezing point of water (0°C). These are frequently found in deep-sea sediments, glaciers, and permafrost. Some bacteria, like Planococcus halocryophilus, can remain metabolically active at temperatures as low as -15°C to -25°C.
- Statement 3 (Correct): Acidophiles are microorganisms that thrive in highly acidic environments, often with a pH below 3.0. For instance, Picrophilus oshimae and Picrophilus torridus can grow at a pH near 0. These organisms are commonly found in sulfuric pools, mine drainage sites, and volcanic areas.