Question

(c) Give some distinctive features of protozoa.
Ans.​

Answer 1

$\large\sf\underline{Protozoa\:}$‎

• For figure refer to the attachment

‎

$\large\sf\underline{Definition\::}$

The heterotrophic protists having life pattern as found in majority of animals are called $\tt\blue{Protozoa}$ .

‎

$\large\sf\underline{Salient\:Characters\:of\:Protozoa\::}$

◎ Unicellular and microscopic .

‎

◎ Morphological variation is noticed in different forms of the group.

‎

◎ Locomotory organelles like cilia or flagella or pseudopodium may be present in different forms of this group. However some forms lack any locomotory structure.

‎

◎ The forms usually show holozoic, holophytic, saprozoic or parasitic mode of nutrition.

‎

◎ Respiration occurs through plasma membrane of the cell.

‎

◎ Presence of one or more contractile vacuoles in the cell and these are used for osmoregulation.

‎

◎ Reproduction occurs mostly by asexual method by binary or multiple fission. But some forms show sexual reproduction by conjugation [ as in Paramoecium. sp ] .

‎

◎ During unfavourable condition some forms may get protection by forming cyst.

‎

◎ Digestion intra - cellular mostly in free living forms. The parasitic forms do not require digestion.

‎

◎ Division of labour for various physiological functions is associated with different membrane bound organelles.

‎

$\large\sf\underline{Examples\::}$

• Amoeba - Amoeba proteus

• Paramoecium - Paramoecium aurelia

• Euglena - Euglena viridis

‎

___________________________‎

!! Hope it helps !!

Note : The answer is not copied :D

Answer 2

Protozoa is an inform al term for a group of single-celled eukaryotes, either free-living or parasitic, which feed on organic matter such as other microorganisms or organic tissues and debris.

EXAMPLE:-

• Amoeba
• Trypanosoma
• Paramecium

Some distinctive features of Protozoa are:-

• Protozoa vary substantially in size and shape. Smaller species may be the size of fungal cells; larger species may be visible to the unai.ded eye.
• Protozoal cells have no cell walls and therefore can assume an infinite variety of shapes. Some genera have cells surrounded by hard shells, while the cells of other genera are enclosed only in a cell membrane.
• Protozoa are heterotrophic microorganisms, and most species obtain large food particles by phagocytosis.
• Some species have specialized structures called cytostomes, through which particles pas.s in phagocytosis.

#NAWABZAADI