Amoeba: Definition and Characteristics

Amoeba is a unicellular organism, which belongs to the kingdom Protista. Amoebas are tiny, microscopic organisms that are found living in freshwater, saltwater, and moist soil. They are known for their shapeless or irregular shape, which makes them difficult to classify.

How Amoeba Ingests its Food?

Amoeba is a heterotrophic organism, which means it cannot make its food. Hence, it needs to ingest its food from the surrounding environment. Amoeba feeds on a variety of microorganisms, including bacteria, algae, and other protozoans. The process of feeding in amoeba involves the following steps:

1. Pseudopodia Formation

Amoeba ingests its food through a process called phagocytosis. Phagocytosis involves the formation of pseudopodia, which are temporary projections of the cell membrane that help in engulfing the food particles. These pseudopodia are formed by the cytoplasmic streaming, which is the movement of cytoplasm within the cell.

2. Encapsulation of Food Particle

Once the food particle is engulfed by the pseudopodia, it is encapsulated within a membrane-bound vacuole called a phagosome. The phagosome is formed by the fusion of the pseudopodia with the cell membrane.

3. Fusion with Lysosome

Once the phagosome is formed, it fuses with a lysosome, which contains digestive enzymes. The enzymes within the lysosome break down the food particle into smaller molecules, which can be easily absorbed by the cell.

4. Absorption of Nutrients

The smaller molecules resulting from the breakdown of the food particle are absorbed by the cell through the process of diffusion. The nutrients are then transported to other parts of the cell, where they are used for various metabolic processes.

Conclusion

In conclusion, amoeba is a unicellular organism that feeds on a variety of microorganisms through the process of phagocytosis. The process involves the formation of pseudopodia, encapsulation of the food particle, fusion with lysosome, and absorption of nutrients. This process helps the amoeba to obtain essential nutrients required for survival.

Amoebas use their pseudopods to ingest food by a method called phagocytosis (Greek: phagein, to eat). ... Inside the cell, the food is enclosed within food vacuoles, digested by enzymes, and assimilated by the amoeba. The amoeba expels particles that are not acceptable as food.