Microbiology Multiple Choice Questions on “Productivity of Aquatic Microorganisms”.
1. The primary producers in the marine system are ________________
A. protozoa
B. cyanobacteria
C. fungi
D. cyanobacteria and eukaryotic algae
Answer: D
Clarification: The primary producers in the marine system are cyanobacteria and eukaryotic algae which predominate in the phytoplankton.
2. The primary producers transform radiant energy into heat energy.
A. True
B. False
Answer: B
Clarification: The primary producers through photosynthesis, are capable of transforming radiant energy into chemical energy (organic compounds).
3. The biological activity of an aquatic ecosystem is dependent upon which of the following factors?
A. number of primary producers
B. amount of chemical energy produced
C. rate of primary production
D. number of deaths of organisms
Answer: C
Clarification: The biological activity of an aquatic ecosystem is dependent upon the rate of primary production performed by the photosynthetic organisms.
4. n which of the following water bodies, the role of photosynthetic organisms is considerably reduced?
A. Lakes
B. Ponds
C. Estuaries
D. Streams
Answer: C
Clarification: In shallow estuaries the role of photosynthetic organisms as primary producers is considerably reduced. Plant growth from the shoreline contributes leaves, stems, and roots of vegetation and other organic detritus.
5. Which of the following aquatic organisms contribute in a small amount to the shallow estuary food web?
A. benthic algae
B. bacteria
C. protozoa
D. nematodes
Answer: A
Clarification: Phytoplankton and benthic algae make a small contribution to the food supply in the food web of shallow estuaries.
6. Which among the following are referred to as the “pasture of the sea”?
A. fishes
B. algae
C. nematodes
D. phytoplankton
Answer: D
Clarification: Plankton, particularly phytoplankton, has been referred to as the “pasture of the sea”. Fish, whales, and squids feed directly on plankton or on larger plankton-feeding animals.
7. The term fertility of oceans is used to express the capacity for the production of inorganic matter.
A. True
B. False
Answer: B
Clarification: The term fertility of oceans is used to express the capacity for the production of organic matter by the organisms present in these waters.
8. What amount of dry organic matter is produced by deep ocean areas?
A. 1g
B. 10g
C. 0.5g
D. 100g
Answer: C
Clarification: The terrestrial environment produces 1 to 10 g of dry organic matter per square meter per day compared to 0.5 g for the deep ocean areas.
9. Which among the following factors are limiting the growth of phytoplankton organisms?
A. carbon dioxide
B. radiant energy
C. water
D. radiant energy,nitrogen
Answer: D
Clarification: The factors generally limiting growth are radiant energy, nitrogen and phosphorus, and the trace elements. The nitrogen, phosphorus and trace elements are made available through the mineralization reactions of microorganisms.
10. Which among the following oceans is the most richest in life?
A. Antarctic Ocean
B. Atlantic Ocean
C. Pacific Ocean
D. Indian Ocean
Answer: A
Clarification: The Antarctic Ocean is described as being richer in life than any other major oceanic area. The richness of nutrients in this region is attributable to the mixing of the waters of the Atlantic, Pacific, and Indian Oceans.
11. In which of the following water bodies, fertility is high?
A. open sea
B. coastal regions
C. lakes
D. rivers
Answer: B
Clarification: Although coastal and estuarine regions provide a less stable physical environment, their fertility exceeds that of the open sea because of the large amounts of nutrients available.
12. Which of the following product is not obtained from dissimilation of organic matter under aerobic conditions?
A. ammonium
B. sulphate
C. methane
D. phosphate
Answer: C
Clarification: Under aerobic conditions the principal products resulting from dissimilation of organic compounds are ammonium, carbon dioxide, sulphate, and phosphate.
13. Which of the following organism have siliceous skeletons?
A. Foraminifera
B. Coccolithophores
C. Radiolaria
D. Cyanobacteria
Answer: C
Clarification: Radiolaria and silicoflagellates have siliceous skeletons whereas foraminifera and coccolithophores produce calcareous skeletons.
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