Largest fresh water protozoa is:
Answer: B
Correct answer: Pelomyxa palustris
Pelomyxa palustris is a giant amoeba of freshwater mud, reaching several millimetres and visible without a lens. It is remarkable in other ways too - multinucleate, with hundreds of nuclei, and containing symbiotic bacteria in place of mitochondria.
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Which of the following organisms will vanish if all the ponds and puddles are destroyed?
Answer: A
Correct answer: Plasmodium
Plasmodium depends on the Anopheles mosquito, which lays its eggs in standing water, so removing every pond and puddle removes the breeding sites and breaks the transmission cycle. This is why drainage and larviciding are the oldest malaria control measures. Trypanosoma uses the tsetse fly and Leishmania the sandfly, neither of which breeds in open water.
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Who gave acellular concept for protozoans?
Answer: A
Correct answer: Dobell
Dobell argued that a protozoan should not be called unicellular, since it is not a cell comparable to one in a metazoan body but a complete organism whose functions are carried out by organelles. The acellular view treats the animal as a whole rather than as a single cell, and it is why the organelles are named for the functions they perform.
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Pellicle is present in:
Answer: A
Correct answer: Amoeba verrucosa
A. verrucosa is unusual among the amoebae in having a thick wrinkled pellicle, which is where its name comes from. The covering makes it sluggish, with short blunt pseudopodia, and it is the exception to the rule that an amoeba is naked.
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First studied protozoa by Leeuwenhoek was:
Answer: C
Correct answer: Vorticella
Vorticella is a stalked ciliate common in pond water and conspicuous under a simple lens because of the way its stalk contracts into a spiral. That visible movement is why it was among the first of the animalcules Leeuwenhoek recorded.
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Food vacuole in Amoeba is analogous to:
Answer: A
Correct answer: Digestive tract of higher animals
The food vacuole is where digestion happens: enzymes are secreted into it, the food is broken down, the products pass into the cytoplasm and the residue is expelled. That is the whole function of a gut, performed within a single cell - which is the point of calling a protozoan acellular rather than unicellular.
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Which of the following protozoan causes African sleeping sickness
Answer: D
Correct answer: Trypanosoma gambiense
T. gambiense causes the chronic West African form of sleeping sickness and T. rhodesiense the acute East African form, both carried by the tsetse fly. T. lewisi is a parasite of rats and harmless to man, and the other two options belong to quite different diseases.
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Which of these is a marine amoeba:
Answer: B
Correct answer: Thecamoeba orbis
Thecamoeba orbis is a marine form, while Amoeba proteus, A. verrucosa, A. radiosa and A. dubia are all freshwater. The distinction has a physiological consequence: living in seawater, which is close to isotonic, the marine forms have little or no need of a contractile vacuole.
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Protozoa are classified on the basis of
Answer: A
Correct answer: locomotory organelle
The traditional classification turns on how the animal moves: pseudopodia in Sarcodina, flagella in Mastigophora, cilia in Ciliata, and nothing at all in Sporozoa. Shape, size and nuclear number vary too widely within each group to serve, whereas the organelle of locomotion is constant and easily observed.
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Organ of defense in protozoans is
Answer: B
Correct answer: trichocysts
Trichocysts lie beneath the pellicle of Paramecium and discharge as fine threads when the animal is disturbed, serving in defence and in anchorage. Nematocysts belong to the cnidarians, and statocysts and otocysts are organs of balance in higher animals.
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