Question

Explain the process of digestion in Amoeba.

Answer 1

Hint:The mode of nutrition in amoeba is holozoic, that is the food is taken by ingestion. The process of digestion requires various enzymes that help in the breakdown of macromolecules into smaller particles.

Complete answer: 1. Amoeba is a unicellular eukaryotic organism that is a protist. It is classified as a protozoan member. All protozoans are heterotrophic organisms that live as predators or parasites, hence they are called primitive relatives of animals.
2. Since amoeba is a single-celled organism, the digestion in it is intracellular digestion. This digestion process is facilitated by certain digestive enzymes. These enzymes break down the large insoluble particles to the simplest molecules.
3. The body of the amoeba forms finger-like temporary projections called pseudopodia. The word pseudo means false and the word podia mean feet, which means the word pseudopodia means false feet.
4. Pseudopodia are extended towards the food particle, they surround it and engulfs it. The food is stored as a food vacuole where its digestion starts. Various digestive enzymes take part in it and finally it is egested or thrown out of the body.
5. When the cell engulfs any foreign particle by putting out pseudopodia, then it is called phagocytosis or cell eating. Similarly, if the liquid is engulfed by a cell in this way, then it is called pinocytosis or cell drinking.
6. The ingested food particle, after digestion, is thrown out of the body, and the nutrition extracted from it is absorbed in the cytoplasm of the amoeba by diffusion. These absorbed nutrients provide the amoeba with energy, and it also facilitates in growth of the organism.
7. Since amoeba is a eukaryotic organism, it contains membrane-bound organelles. One such cell organelle is the lysosome which contains hydrolytic enzymes like proteases, nucleases, lipases, and carbohydrates.
8. The food vacuole formed in the amoeba as a result of ingestion is combined with lysosomes for the process of digestion. The absorbed food supplies energy and the excess amount of food are stored in the form of glycogen and lipids.

Note: Any foreign particle that enters a cell, enters it through endocytosis. The food vacuole formed as a result of this is also called gastric vacuole and then it leaves the cell by the process called exocytosis.