BSc 1st Year Lower Non-chordates Phylum Protozoa: Miscellaneous Sample Model Practice Question Answer Papers
BSc 1st Year Lower Non-chordates Phylum Protozoa: Miscellaneous Sample Model Practice Question Answer Papers: BSc is a three-year program in most of the universities. Some of the universities also offer BSc Honours. After getting enrolled for BSc, there are certain things you require the most to get better grades/marks in BSc. Out of those, there are BSc Study Material, BSc Sample Model Practice Mock Question Answer Papers along with BSc Previous Year Papers. At gurujistudy.com you can easily get all these study material and notes for free. Here in this post, we are happy to provide you BSc 1st Year Lower Non-chordates Phylum Protozoa: Miscellaneous Sample Model Practice Question Answer Papers.
BSc 1st Year Lower Non-chordates Phylum Protozoa: Miscellaneous Question Answers
Q.1. Give differences between the following:
1. Amoeboid and Euglenoid Movement
1. It takes place by pseudopodia formed by the streaming flow of the cytoplasm.
2. Exhibited by Sarcodina, some masti-gophores and sporozoans.
1.Takes place by contraction of contractile fibres, the myonemes.
2. Found in Euglena.
2. Axopodia and Filopodia
1. These are straight and radiating pseudopodia.
2. Central axial rod present.
4. Formed by the ectoplasm and endoplasm.
5. These are found in Actinophrys.
1. These are filamentous pseudopodia.
4. Only endoplasm takes part in the formation.
5. These are found in Euglypha.
3. Autogamy and Syngamy
1. In autogamy only one individual is involved.
2. Two gametic nuclei of the same individual fuse to form a homozygous diploid nucleus or synkaryon.
3. Self-fertilisation takes place.
4. It occurs in Paramecium caudatum.
1. In this case two individuals of the same specics or gametes are involved.
2. Two individuals or gametes fuse to form a zygote.
3. Cross-fertilization takes place.
4. It is found in Monocystis and Plasmodium.
4. Schizogony and Multiple Fission
1. Nuclear division is followed by cytoplasmic division.
2. Daughter nuclei are scattered in the parent body.
3. Found in Plasmodium and Monocystis.
1. Not followed immediately by cytoplasmic division.
2. Nuclei arranged at the periphery of the parent body surrounded by cytoplasm.
3. Found in Plasmodium and Aggregata.
Q.2. What is the difference in Asexual Reproduction of Euglena and Paramecium.
Asexual Reproduction in Euglena : In Euglena asexual reproduction takes place by longitudinal binary fission. Nucleus divides longitudinally into two with duplication of cytopharynx, reservoir eye spot, blepheroplasts and contractile vacuole. A constriction arises at the anterior end and passes backward resulting in longitudinal splitting of the body. One of the two daughter euglenae retains the old flagellum, while a new one is developed by the other.
Asexual reproduction in Paramecium : During favourable conditions of food, water and temperature paramecium multiplies by transverse binary fission. The animal stop feeding and the micronucleus divides into two which move apart towards the opposite ends. The macronucleus elongates and gets constricted into two amitotically. A transverse constriction appears in the middle of body which deepens and divides the body into two equal halves. The oral groove of the parent is retained by one half and the mouth and cytopharynx by other. These, later an, regenerate the essential parts.
1. Contractile Vacuole
Contractile vacuoles are osmoregulatory organelles, found in ciliates, flagellates and Sarcodina but are absent in the members of class Sporozoa. Their structure, position and number varies in various protozoans. They gradually increase in size until they reach the maximum and then suddenly contract to expel out their water content.
In Amoeba, a single contractile vacuole appears as a clear space in the endoplasm. After attaining its full size, it throws out its contents through the pellicle. Soon a new contractile vacuole appears where the old one had disappeared. As it grows it moves towards the nucleus and then backwards.
In flagellates and ciliates, the position of contactile vacuole is more or less mixed. In Paramecium, there are two large contractile vacuoles, one on either side of the body lving between the ectoplasm and endoplasm close to the dorsal surface. Each contractile vacuole is surrounded by 6-10 elongated radiating canals. Each opens to the outside through a distinct discharge canal in the pellicle of dorsal side. In Balantidium and Nyctotherus, the contractile vacuole is situated close to the cytopyge.
The main function of contractile vacuole is osmoregulation. The animal gets rid of excess water in the body by pumping it out with the help of contractile vacuole. The contractile vacuoles also help in the removal of nitrogenous wastes from the body.
In unicellular organisms like Amoeba, Paramecium, etc. the excess water entering through the body surface and along the food intake is collected in the contractile vacuole. On attaining the full size, the vacuole contracts and the fluid is forced out through the body surface. In Amoeba, the contractile vacuole disappears and in its place a new contractile vacuole is formed. In Paramecium, the excess water from cytoplasm is collected in the microtubules of endoplasmic reticulum from where it reaches the radiating canals. On getting filled with water, these converge and discharge their contents in the contractile vacuole. The contractile vacuole forces out this water through a pore in the pellicle. This regulation of water in the body by contractile vacuole is called osmoregulation.
These are fine hair-like, protoplasmic processes which emerge from the cytoplasm. In class Ciliata, they persist throughout life, while the adult members of class Suctoria are without cilia. The cilia are present only in their young stages.
Encystment is a device found in the organisms of phylum Protozoa to protect their body from the unsuitable environmental conditions. In extreme cases of hot, cold or drought when the life of the animal is threatened, the protozoans secrete a protective cyst around their body and pass the unfavourable period remaining inactive. The nature of the cyst varies among animals. It is chitinous and three-layered in Amoeba and gelatinous in Euglena. At the approach of favourable conditions the cyst dissolves and the animal is set free to start free existence. Encystment is useful in the following ways:
1. Protective device to tide over unfavourable environment.
2. Helps in the dispersal of animal since the cysts are blown by the air, and carried from place to place by other organisms and in most endoparasitic forms it is the only means of dispersal.
3. Encystment is followed by the division of body, or certain individuals only during encysted condition. Thus it is a means of race multiplication.