Digestion in amoeba
Amoeba is a simple, unicellular organism which is found at the bottom of fresh water, It contains jelly like cytoplasm with a clear nucleus, many food vacuoles and contractile vacuoles. Because amoeba is unicellular,It means a single cell performs all the function like digestion, respiration, reproduction etc. Amoeba is omnivorous. It means it can feed both on plants and micro organisms. The mode of nutrition in amoeba is holozoic. Holozoic means it engulf the solid food particles. The digestion in amoeba is intracellular. It means digestion takes place within the cell.
The main steps of nutrition in amoeba:
Because amoeba is a unicellular organism. It does not have any mouth it can ingest food through any place on the surface of cell membrane by making false feet. These false feet known as pseudopodia.
- Important points: Pseudopodia are finger like cytoplasmic projections which used to capture food as well as for locomotion.
Amoeba has a sense of ability to accept food particles. When the food is found, it extends its pseudopodia. Pseudopodia just wrap around the food particle. The food particle enclose in the food vacuole.
The food vacuole contains digestive enzymes. With the help of digestive enzymes, the engulfed food is digested in the food vacuoles. Two enzymes amylase and proteinase have been reported. Thus amoeba can digest carbohydrates and proteins.
Now the digested food becomes liquid in the food vacuole. Now this digested food diffuse to the cytoplasm from the food vacuole. It is done by simple diffusion method.
- Important point:
The undigested food remains in the food vacuole.
This digested food becomes the part of protoplasm. Some food is used to generate energy by the process of respiration and remaining food is stored as reserved food in the protoplasm.
Like mouth, amoeba has no definite anus (opening aperture) for the removal of the undigested food. So this undigested food sent to near the cytoplasmic membrane and thrown in the surrounding. This process is known as egestion.