Question

Passive food ingestion in Amoeba is known as

• A. Import
• B. Circumfluence
• C. Circumvallation
• D. Invagination

Answer 1

Answer: (A)

Amoeba ingests food in four ways.

1. Import- This method involves the taking in of food on contact. The food passively sinks into the body by rupturing plasmalemma and ectoplasm at the point of contact. The ruptured site soon heals up.
   
2. Invagination - The food is adhered by the toxic and sticky secretion of ectoplasm. The food organism is sucked in upon contact with the ectoplasm, by the formation of the ectoplasmic tube which later becomes a food vacuole.
   
3. Circumfluence - Amoeba extends its pseudopodia around the motionless organism like bacteria on contact and envelops it completely with cytoplasm. The enclosing of the captured organism results in the formation of food vacuole.
   
4. Circumvallation - Amoeba engulfs an active prey like a flagellate or ciliate.It sends out pseudopodia around the prey, forming a cup-like structure called food-cup. The opening of the food-cup constricts leaving a pore which soon closes.
   

Thus, the correct answer is option A.