Amoeba is called naked because:
Answer: B
Correct answer: It has a delicate plasma membrane
Naked here means unprotected: the amoeba has only its thin plasma membrane, with no pellicle, test or shell over it. That is precisely what allows the cell to change shape freely and put out pseudopodia, and it is the feature distinguishing the naked amoebae from the shelled forms such as Arcella and Difflugia.
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Hay-infusion method is used for the culture of:
Answer: A
Correct answer: Amoeba and paramecium
A hay infusion is prepared by steeping dried hay or grass in water and leaving it to stand. Bacteria multiply on the decaying material and provide food for the protozoa, which appear in succession over days - flagellates first, then ciliates such as Paramecium, then amoebae. It is the standard laboratory method for obtaining both.
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Branch of zoology related with the study of protozoans is:
Answer: D
Correct answer: Protozoology
The name is formed regularly from protozoa and the suffix for a branch of study. The other three are not established terms - parazoology would suggest a study of the Parazoa, the sponges, which is a different group altogether.
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Multinucleate Amoeba is:
Answer: B
Correct answer: Pelomyxa plaustris
Pelomyxa palustris carries hundreds of nuclei in a single large cell, which is exceptional among the amoebae. It also lacks mitochondria, relying instead on symbiotic bacteria, and both features mark it out as an unusual member of the group.
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Natural death does not occur in:
Answer: B
Correct answer: Protozoans
A protozoan divides into two daughters, each as young as the other, so nothing is left behind to die. The individual is potentially immortal and the line ends only through accident, predation or starvation. Natural death in the ordinary sense appears with the separation of body from germ cells in multicellular animals.
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Which of the following is not a characteristic feature of protozoans?
Answer: C
Correct answer: cell membrane as an outer body covering
A bare plasma membrane distinguishes nothing, since every cell has one, and many protozoa have more - a firm pellicle in Paramecium and Euglena, a shell in the foraminiferans, a test in the arcellids. Binary fission, the contractile vacuole and pseudopodia are all features the group is characterised by.
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Which of the following class of protozoa does not generally contain contractile vacuole?
Answer: A
Correct answer: Sporozoa
Sporozoans are parasites living in the body fluids of their hosts, which are isotonic with them, so no water floods in and no organelle is needed to pump it out. The contractile vacuole is essentially a fresh water adaptation, and its absence follows directly from where these animals live.
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Which class does the malarial parasite belong to?
Answer: D
Correct answer: sporozoa
Plasmodium is placed in the Sporozoa, whose members are all parasites, have no organelle of locomotion in the adult stage, and reproduce by multiple fission producing spores. The four classes of the traditional scheme divide on exactly this point - how, or whether, the organism moves.
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Contractile vacuole in Amoeba and Euglena differ in:
Answer: A
Correct answer: Fixed place at anterior and with many small vacuoles around it
In Euglena the contractile vacuole sits permanently at the anterior end beside the reservoir, fed by a ring of small accessory vacuoles that discharge into it. In Amoeba there is no fixed position at all - the vacuole forms wherever it happens to and is carried about as the cytoplasm streams.
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Nucleus in Amoeba is:
Answer: C
Correct answer: Bun-shaped
The nucleus of Amoeba proteus is a flattened biconcave disc, conventionally described as bun-shaped, and it is carried passively in the streaming cytoplasm. Its shape is one of the features used to distinguish species of the genus under the microscope.
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