Question

Amoeba sticks to substratum by means of
A)Rough surface
B)Plasmalemma
C)Protein
D)None of the above

Answer 1

Hint: Amoeba are unicellular organisms that do not possess a definite shape. They are able to alter their shape by means of specialised structures known as pseudopodia. Amoeboid cells are found in protozoa, algae, fungi and also some animals.

Complete answer:
Amoeba do not possess a cell wall as a result of which they are capable of moving freely. They move by the help of pseudopodia which typically are bulges of the cytoplasm formed due to the action of actin filaments. Some of the amoeba cells may be enclosed within a hard shell whereas some occur freely without the presence of any hard shell. The shells are made up of calcium, chitin, silica or small grains of sand. Amoeba consists of a contractile vacuole by means of which it regulates osmotic pressure.

The vacuole helps to expel water out of the cell otherwise due to accumulation of excess water the cell would swell up and burst. Another specialised part composed by amoeba is plasmalemma. Plasmalemma is a lipid bilayer that does not consist of a cell wall and contain small microvilli-like projections extending from it. It is by means of plasmalemma that amoeba can attach to the substratum.

Hence, the correct answer is option (B)

Note: Amoeba is known to feed by the help of phagocytosis. They are known to extend their pseudopodia around the food substance and gradually engulf it. They might feed either on living organisms or dead organic matter.