Q.Give an account of pseudopodia.

Pseudopodia are temporary cytoplasmic projections used for movement and feeding in amoeboid protozoans; they are of four types - lobopodia, filopodia, axopodia and reticulopodia.

Account of pseudopodia:

• PSEUDOPODIA (singular: pseudopodium; meaning "false feet") are temporary, blunt or pointed projections of the cell surface formed by the streaming (flowing) of the cytoplasm (ectoplasm and endoplasm) in amoeboid cells.
• They are NOT permanent structures - they are formed and withdrawn as needed.

Functions:

• LOCOMOTION: the animal moves by extending a pseudopodium forward and flowing its cytoplasm into it (amoeboid movement).
• FEEDING (food capture): pseudopodia surround and engulf food particles, forming a food vacuole (phagocytosis).

Types of pseudopodia:

1. Lobopodia: broad, blunt, finger-like pseudopodia with both ectoplasm and endoplasm, e.g. Amoeba, Entamoeba.
2. Filopodia: slender, thread-like, pointed pseudopodia formed mainly of ectoplasm, e.g. Euglypha.
3. Axopodia (actinopodia): long, thin, radiating pseudopodia, each supported by a stiff central axial filament, e.g. Actinophrys, Actinosphaerium (heliozoans). …