Protists: Occurrence and Structure (With Diagram)

In this article we will discuss about the Occurrence and Structure of Protists.

Occurrence of Protists:

Protists are mostly aquatic organisms, therefore, they are found in the sea, fresh water and moist soil. Many protists are found in water bodies in the form of plankton. Some protists live in the bodies of animals as parasites.

Structure of Protists:

Protists are microscopic organisms. Cell structure is eukaryotic. Protists is surrounded by plasma lemma (cell membrane). There may be an outer covering of pellicle, cuticle, shell or cellulose wall. It contains organelles like mitochondria, Golgi complex, endoplasmic reticu­lum, 80S ribosomes, etc.

They have typical 9+2 fibrils. Nucleus has typical structure—porous nuclear envelope, chromatin, nucleolus and nucleoplasm. Many forms have more than one similar or dissimilar nuclei. Centrioles occur in a number of types. Photosynthetic forms contain chloroplasts with internal thylakoids. Cilia and flagella occur in a number of forms.