Question

Type of pseudopod present in Amoeba proteus is
a. Lobopodia
b. Axopodia
c. Filopodia
d. None of the above

Answer 1

Hint: Amoeba must be one of the most commonly known protozoans among us. They possess arm-like structures called pseudopods, which facilitate their movement and ingestion. The pseudopods can be extended in all the directions.

Complete answer:
The pseudopods, also known as pseudopodium, are temporary or semi-permanent structures filled with cytoplasm and consist of actin filaments and sometimes with microfilaments. Along with motility and ingestion, they are also important to locate and sense the food. It can be categorised based on multiple criteria like morphology and number of projections.

Now, let us understand the types of pseudopods in the options.
> Lobopodia – These are the commonly found pseudopods among parasitic amoeba. They are long and blunt finger-like structures composed of ectoplasm only or both ectoplasm and endoplasm. It forms slowly with gradual flow of ectoplasm into them. However, Entamoeba histolytica is an exception.

> Axopodia – This is a semi permanent structure, which is a characteristic feature of actinopods. They are made of an array of microtubules along with a fine needle like radiating pseudopods enclosed by cytoplasm. Axopodia are vital for phagocytosis as they act rapidly. Example: Radiolaria, Heliozoa.

> Filopodia – Also known as filose pseudopods, they are composed of microfilaments and protein bundles like fimbres and fascias, held together loosely by crosslinking. They are filiform (thread like) with pointed ends occasionally forming branched networks.

Hence, the correct answer is option (A).

Note: The remaining types of pseudopodia are reticulopodia and lamellipodia. Reticulopodia or myxopodia have a complex structure with multiple pseudopods joined together whose primary purpose is food ingestion. Examples: Foraminifera, Chlor Arachnea. Lamellipodia is a flat and broad pseudopodia composed of microfilaments.