Microbiology Multiple Choice Questions on “Aquatic Microorganisms.
1. Which of the following zones have considerable rooted vegetation?
A. littoral zone
B. limnetic zone
C. profundal zone
D. benthic zone
Answer: A
Clarification: There is usually a fairly large littoral zone along the shore which has considerable rooted vegetation and includes regions where light penetrates to the bottom.
2. Which of the following layer is composed of soft mud or ooze?
A. Photic zone
B. Limnetic zone
C. Benthic zone
D. Profundal zone
Answer: C
Clarification: The benthic region is composed of soft mud or ooze at the bottom. Profundal region exists at much greater depths of the water body whereas the littoral zone is present along the shore.
3. In which of the following seasons does the nutrient concentration falls at a drastically lower level?
A. Winter
B. Spring
C. Summer
D. Autumn
Answer: C
Clarification: Occurrence of algal blooms during the spring and autumn results in lowering the nutrient concentration during summers.
4. Rapidly expanding urbanization makes it difficult to generalize upon typical microbial flora of streams.
A. True
B. False
Answer: A
Clarification: The drastic environmental changes in streams and rivers created by rapidly expanding urbanization on the one hand and changes in farming practices on the other make it impossible to generalize upon typical or characteristic microbial flora.
5. The coastal adjunct of the marine ecosystem is __________________
A. stream
B. estuary
C. river
D. lake
Answer: B
Clarification: An estuary is the coastal adjunct of the marine ecosystem. It is a semi-enclosed coastal body of water which has a free connection with the open sea.
6. The Chesapeake Bay, one of the world’s major estuarine system serves as the receiving basin for how many rivers?
A. 4
B. 6
C. 3
D. 9
Answer: D
Clarification: The Chesapeake Bay, one of the world’s major estuarine system serves as the receiving basin for nine major rivers, draining much of southern New York State, Pennsylvania, Maryland and Virginia.
7. In regions of the estuary that are nutritionally poor, it is more likely to find which of the following organisms?
A. coliforms
B. appendaged bacteria
C. viruses
D. fecal streptococci
Answer: B
Clarification: In regions of the estuary that are nutritionally poor, one is likely to find the budding and/or the appendaged bacteria, in addition to pseudomonads.
8. The characteristic color of the Red Sea is associated with heavy blooms of __________________
A. diatoms
B. cyanobacteria
C. dinoflagellates
D. chlamydomonads
Answer: B
Clarification: The characteristic color of the Red Sea is associated with heavy blooms of a cyanobacterium, Oscillatoria erythraea, which contains the pigments phycoerythrin and phycocyanin.
9. Aquatic bacteria tend to be Gram-negative.
A. True
B. False
Answer: A
Clarification: In general, aquatic bacteria tend to be Gram-negative. It is thought that the Gram-negative envelope provides a structure better suited to support life in nutritionally dilute aquatic environments than the Gram-positive cell wall.
10. Which of the following genus of bacteria is not found in fresh waters?
A. Pseudomonas
B. Flavobacterium
C. Aeromonas
D. Vibrio
Answer: D
Clarification: Species of the following genera are commonly found in freshwater: Pseudomonas,
Flavobacterium, Aeromonas and Alcaligenes. Vibrio are found in marine or estuarine waters.
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