Question

In which group, the locomotory organelles are absent?
(a) Flagellate
(b) Sarcodina
(C) Sporozoan
(d) Ciliata

Answer 1

Hint: The kingdom Protista is divided into four groups based on the type of locomotion exhibited by their members. The locomotory organelles are absent in the group where all its members are endoparasites i.e they spend their life by inhabiting themselves in the body of other organisms.

Complete answer:
Protozoan protists are classified into four groups based on the type of locomotion exhibited by its members: Mastigophora, Sarcodina, Sporozoan, and Ciliates. Sporozoans are non- motile and are devoid of any locomotory organelles. All the sporozoan have been found to be endoparasites i.e they live in the body of other organisms and obtain their nutrition from them. E.g .Plasmodium, .Monocystis.

Additional Information:
- Mastigophora possesses flagella as their locomotory apparatus. They can be free- living aquatics, parasites, commensals, or symbionts. E.g. Trypanosoma, Leishmania. They are also known as zooflagellates.
- Sarcodina or Rhizopoda is a group for members that develop pseudopodia or temporary cytoplasmic extensions for locomotion. Entamoeba histolytica.
- Ciliata are the protozoans that have developed numerous hair- like projections called cilia all over their body during a part or whole of their life cycle. These locomotory organelles are helpful in locomotion as well as feeding. E.g .Paramecium.
- The body of Sporozoans is surrounded by an elastic and flexible membrane known as pellicle or cuticle. Their life- cycle consists of two distinct reproductive stages or phases i.e asexual and sexual.
So, the correct answer is ‘(C) Sporozoan.’

Note: Pseudopodia is a type of locomotory apparatus that is usually observed in the protozoans belonging to the group of Sarcodina or Rhizopoda. These are temporary membranous extensions of the cell membrane for locomotion or for the ingestion of food. The fibroblast cells along with the help of microtubules and microfilaments in the cytoplasm produce these cytoplasmic extensions.