paramecium-1 - contraction pass over the cell body like...

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Paramecium 1 Paramecium Paramecium is a ciliate protozoan. Ciliates’ bodies are covered with fine cytoplasmic hair-like structures called cilia. Flickering movements of the cilia propel the organism through the water and also create feeding currents. Paramecium, illustrated here, is a ciliate. In describing its structure, comparisons will be made with amoeba. It is suggested, therefore, that amoeba is studied first. Unlike amoeba, paramecium has a distinct and permanent shape and certain areas of cytoplasm, (cell organelles), are specialised to carry out specific functions. Locomotion . Individual cilia bend and straighten The whole complement of cilia beat in rapidly in such a way that the recovery stroke offers a rhythmic pattern, (metachronal minimal resistance and the bending stroke helps rhythm), so that the waves of propel paramecium through the water.
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Unformatted text preview: contraction pass over the cell body like wind blowing through ripe corn. . If paramecium encounters an obstacle, it reverses the ciliary beat and moves back. It then changes direction slightly and moves forward. It will do this repeatedly until it gets past the obstruction. This reaction also shows that paramecium is sensitive to stimuli (in this case, the stimulus of touch). contractile vacuole (about to empty)) contractile vacuole (filling) meganucleus (controls basic processes) micronucleus (controls reproduction) cilia anal pore cytostome (cell ‘mouth’) oral groove feeding current food vacuole Paramecium direction of movement power stroke recovery 1 Paramecium hits an obstacle 2 reverses its ciliary beat 3 turns slightly 4 moves forward again cytoplasm 60µ © D.G. Mackean...
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