31. Match the organisms in Column I with the characteristics in Column II
Column I Column II
P. Methanococcus 1. Halophile
Q. Dunaliella 2. Acidophile
R. Sulfolobus 3. Mesophile
S. Escherichia 4. Barophile
P Q R S
(a) 4 3 2 1
(b) 3 2 4 1
(c) 2 1 4 3
(d) 4 1 2 3
Dunaliella represents a halophile alga that thrives in high-salt environments, while the matching pairs extremophiles with their defining traits. The correct option identifies each organism’s optimal growth condition accurately. This MCQ tests knowledge of microbial ecology central to biotechnology and molecular biology studies.
Organism Characteristics
Methanococcus grows optimally under high hydrostatic pressure as a barophile methanogen from deep-sea vents. Dunaliella, a green alga, tolerates extreme salinity up to 5 M NaCl, classifying it as a halophile. Sulfolobus, an archaeon, prefers acidic hot springs (pH 2-3), marking it acidophile. Escherichia coli functions best at neutral pH and moderate temperatures (20-45°C) as a mesophile.
Correct Matching
Pairings align as P-4 (Methanococcus: barophile), Q-1 (Dunaliella: halophile), R-2 (Sulfolobus: acidophile), S-3 (Escherichia: mesophile). This matches option (d) 4 1 2 3. These traits reflect adaptations: barophily aids deep-ocean survival, halophily uses glycerol for osmosis, acidophily employs heat-shock proteins, and mesophily suits gut habitats.
Options Breakdown
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(a) 4 3 2 1: Wrong; assigns mesophile to Dunaliella (ignores salt tolerance) and halophile to Escherichia (not salt-adapted).
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(b) 3 2 4 1: Wrong; labels Methanococcus mesophile (overlooks pressure needs) and Sulfolobus barophile (prefers acidity over depth).
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(c) 2 1 4 3: Wrong; misplaces acidophile on Methanococcus (methanogen, not acid-lover) and barophile on Sulfolobus (acidophile primarily).
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(d) 4 1 2 3: Correct; precisely matches documented optima for each.
| Option | P (Methanococcus) | Q (Dunaliella) | R (Sulfolobus) | S (Escherichia) | Status |
|---|---|---|---|---|---|
| (a) | 4 (✓ Barophile) | 3 (✗ Mesophile) | 2 (✓ Acidophile) | 1 (✗ Halophile) | Incorrect |
| (b) | 3 (✗ Mesophile) | 2 (✗ Acidophile) | 4 (✗ Barophile) | 1 (✗ Halophile) | Incorrect |
| (c) | 2 (✗ Acidophile) | 1 (✓ Halophile) | 4 (✗ Barophile) | 3 (✓ Mesophile) | Incorrect |
| (d) | 4 (✓ Barophile) | 1 (✓ Halophile) | 2 (✓ Acidophile) | 3 (✓ Mesophile) | Correct |
Exam Relevance
This question appears in GATE Biotechnology and CSIR NET Life Sciences, emphasizing extremophile classification. Understanding these aids bioreactor design, biofuel production from Dunaliella, and astrobiology research. Practice similar matchings on halophile acidophile barophile mesophile traits for competitive exams.
