Question

Describe the process of nutrition in amoeba. Draw a labeled diagram to show the various steps of nutrition in amoeba.

Answer 1

Hint: Nutrition in amoeba occurs through a process called phagocytosis. In this process, the entire organism engulfs the solid food particles.

Complete answer:
In Amoeba, the mode of nutrition is known as holozoic nutrition that involves the ingestion, digestion, and egestion of foodstuffs. Amoeba is a unicellular organism. It has the ability to alter its shape. Amoebas are generally parasitic or free-living in damp environments.
Nutrition in amoeba includes the following process:-
Ingestion - Amoeba has no mouth for the ingestion of food. It ingests the food by using its pseudopodia. The food is engulfed forming a food vacuole.
Digestion- The food is digested by digestive enzymes present in the cytoplasm which breaks the food into small soluble molecules by chemical reactions.
Absorption: The digested food present in the food vacuole diffuse into the cytoplasm. After this, the food vacuole disappears.
Assimilation - Assimilation is a process that involves the gain of energy from food through respiration and the remaining part of the food is used for growth.
Egestion: The undigested food material moves to the surface of the cell where it is thrown out of the body.

Note:
1. In some amoeba, nutrition takes place by pinocytosis which is also known as fluid endocytosis in which the small particle suspended in extracellular fluid and brought into the cell through the invagination of the cell membrane that resulted in a suspension of particles within a small vesicle inside the cell.
2. The source of food varies among amoebae. Some amoebae are detritivores that eat dead organic matter while some are predatory and live by consuming bacteria and protists.

Figure: Steps involved in the nutrition of amoeba