An amoeba is a type of single-celled protozoal organism. Nutrition in an amoeba occurs through a process called phagocytosis where the entire organism pretty much engulfs the food it plans on eating up. The image below summarizes the stepwise process through which nutrition in amoeba occurs.
This food is mostly tiny bacteria, algae or other plant or dead animal matter available in the surrounding of the amoebas. One wonders how these amoebas, which do not have a mouth and no suction mechanism actually take in food since they’re just these shapeless cells.
Amoebas take in nutrients via phagocytosis and pinocytosis. Phagocytosis is what occurs when an amoeba surrounds a solid food particle with its pseudopods to form a vacuole (known as a phagosome) in which digestion of the food particle then occurs. Pinocytosis is a similar process, but it has to do with the ingestion of a liquid via the budding of the cell membrane of the amoeba to make a vesicle similar to that formed during phagocytosis.
Once the nutrients enter an amoeba via the vesicles formed during phagocytosis or pinocytosis, then the nutrients within the vesicle must undergo digestion. This occurs when the vacuole fuses with a lysosome that contains digestive enzymes