Question

The reason for Pseudopodia formation is
A. Difference in the viscosity
B. Change in temperature
C. Chemical changes
D. Difference in pressure

Answer 1

Hint: We can define the pseudopodium as a temporary projection of the cytoplasm, which is mostly formed by ectoplasm. These are the characteristic organelles of Sarcodina, some Sporozoa and many Mastigophora, where the pellicle is not clear. They act as motor and nutritional organs.

Complete answer:
We have to remember that the locomotion in amoeba is creepy in nature and depends on direct and close contact with the substrate. Amoeba is an unicellular protozoa which under microscope appears as irregular translucent mass and colourless. Crawling in an amoeba involves the formation of finger-shaped protrusions called pseu­dopodia, and this type of movement is known as the amoebic movement.
During movement, one or more pseu­dopodia such as blunt fingers form in the direction of movement in the amoeba. The projections are increasing due to the accumulation of cytoplasm from other parts of the body.
We know that in the amoeba, these animals move by throwing the pseudopodium which is called the amoeba movement. This is the most primitive type of movement caused by contractility and is also characteristic of Sarcodina and many sporozoa.
In the direction in which amoeba moves, a new pseudopodium is formed and the pseudopodium that is situated on the opposite side disappears slowly.
The main reason for the formation of pseudopodia is change in viscosity other factors like temperature, pressure and chemical have no effect on amoeboid movement
So, the correct answer is “Option A”.

Note:
We have to remember that effective movement occurs only when the animal (amoeba) is in contact with the substrate, not when it is brought to the surface of the water. The pseudopodium tip can attach to the substrate by releasing the sticky sap and the whole animal slides forward into the pseudopodium. Movement speed usually varies between 0 and 5 microns per second. Under favourable conditions, the speed can reach up to 25mm per hour. It varies with temperature and slowly increases to $30^{o}C$. The movement stops completely at $33^{o}C.$