In this article you will get detailed information about nutrition in Paramecium with various steps. For your better understanding, we are taking one species of paramecium is P. caudatum. It is mostly asked in in written examination. So, concentrate your mind and read this article.
Nutrition in Paramecium
Paramecium follows holozoic mode of nutrition like Amoeba. They feed small microorganism suspended in water as bacteria, diatoms, small algae, yeast, protozoa, etc. Paramecium swim place to place in the search of food. Its food catching apparatus is much more specialized than Amoeba and Euglena.
Taking of food succeeded from oral groove present at one side that leads to a ciliated chamber called Vestibule. The Vestibule opens into a large opening is called Cytostome, or “cell mouth” laying at the bottom of buccal cavity. Paramecium has many cilia around the body which helps in the food capturing and also for their movement.
Steps of Holozoic Nutrition in Paramecium
Steps of holozoic nutrition in paramecium take place by the following steps – ingestion, digestion, absorption, assimilation and egestion.
1. Ingestion in Paramecium
- Ingestion of food in paramecium taken by a definite cell mouth or cytostome (cyto = cell, stoma= mouth) that is found at the bottom of buccal cavity.
- Food vacuoles are formed at the cytostome and then are circulated through the cytoplasm as digestion occurs.
- During feeding the cilia of oral groove beat strongly than the other cilia of the body. Cilia produce strong water current directed towards the oral groove.
- Food contained water enters into the vestibule. The vestibular cilia allows only small food particles and rejected the large food particles. Small food particles directed into cytostome through buccal cavity.
- After cytostome food passes into a non ciliated tube, called the cytopharynx, which extends from the cytostome deep into the cytoplasm. When cytopharynx filled with food particles, a food vacuole is separated into the cytoplasm.
2. Digestion in Paramecium
- Digestion in Paramecium follows “intracellular digestion”. The food containing food vacuoles surrounded by a thin film of water is circulated around the body by a slow streaming movement of endoplasm called cyclosis.
- The movement of food vacuoles are first posteriorly, then forwardly and aborally and again posteriorly and orally up to cytopyge (cyto = cell, pyge = anus).
- Digestive enzymes proteases, carbohydrases and lipases are secreted by lysosomes. The digestion of food first increasingly in acidic medium, but latter gradually become alkaline. The alkaline phase is the result of the secretion of enzymes in vacuoles.
3. Absorption in Paramecium
- The digested food present in the food vacuole of Paramecium is absorbed directly into the cytoplasm by diffusion.
- After absorption of food, the food vacuole shrinks and size of cell become decreased.
4. Assimilation in Paramecium
- The digested food particles are passes into the cytoplasm called assimilation.
- Digested products are glycogen and fat globules diffused into the surrounding cytoplasm, it may stored or used for vital activities and growth.
5. Egestion in Paramecium
- The undigested particles is expelled out from the body through an opening is called cytopyge or anal spot. It is located on the ventral surface or posterior to cytostome.
Also read this article – Paramecium: Classification, Habitat, Structure, Locomotion, Nutrition
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