Microbiology Multiple Choice Questions on “Aquatic Environment”.
1. The moisture contained in clouds and precipitated as snow,hail,rain etc constitutes _________________
A. Atmospheric water
B. Surface water
C. Groundwater
D. Subterranean water
Answer: A
Clarification: The moisture contained in clouds and precipitated as snow, sleet, hail and rain constitutes atmospheric water. The air is washed by atmospheric water.
2. The surface waters are susceptible to contamination with microorganisms from _______________
A. the air
B. the surface runoff
C. precipitation
D. atmospheric water and the surface runoff
Answer: D
Clarification: The surface waters are susceptible to contamination with microorganisms from atmospheric water (precipitation), the surface runoff from soil and any wastes deliberately dumped into them.
3. Which of the following is subterranean water?
A. Atmospheric water
B. Surface water
C. Groundwater
D. Rainwater
Answer: C
Clarification: Groundwater is subterranean water that occurs where all pores in the soil or rock-containing materials are saturated.
4. Wells less than ___________ deep are considered to be shallow.
A. 1 ft
B. 100 ft
C. 50 ft
D. 1000 ft
Answer: B
Clarification: Wells are made by sinking a shaft into the ground to penetrate the groundwater level. Wells less than 100 ft deep are considered to be shallow.
5. Thermus aquaticus, a common bacterial inhabitant generally prevails in temperatures of ____________
A. 00 C
B. 30-400C
C. 70-720C
D. 80-850C
Answer: C
Clarification: Thermus aquaticus, a common bacterial inhabitant of hot springs has an optimum growth temperature of 70 to 720C.
6. Hydrostatic pressure increases the boiling point of water but does not change the solubility of nutrients.
A. True
B. False
Answer: B
Clarification: Hydrostatic pressure increases the boiling point of water. It affects chemical equilibrium which in turn results in lowering of pH and a change in the solubility of nutrients such as bicarbonate.
7. Primary producers are found growing in which of the following layers of water?
A. upper layer
B. middle layer
C. intermediate layer
D. bottom layer
Answer: A
Clarification: In most aquatic habitats the primary producers i.e. algae have their growth restricted to the upper layers of waters through which light can penetrate.
8. The degree of salinity in freshwater is nearly zero.
A. True
B. False
Answer: A
Clarification: The degree of salinity in natural waters ranges from near zero in freshwaters to saturation in salt lakes.
9. The microorganisms from lakes and rivers can grow at a salt concentration of _________
A. 2.5 to 4 percent
B. 5 percent
C. below 1 percent
D. above 1 percent
Answer: C
Clarification: Microorganisms from lakes and rivers are salt sensitive and do not grow at a salt concentration of more than 1 percent whereas marine microorganisms are halophilic.
10. Which of the following compounds are required for the growth of saprophytic bacteria and fungi?
A. organic compounds
B. nitrates
C. phosphates
D. mercury
Answer: A
Clarification: Organic compounds are required for the growth of saprophytic bacteria and fungi whereas nitrates and phosphates are important for the growth of algae.
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