Question

The organism shown below shows vegetative cells of Oscillatoria. This organism is photoautotrophic and represents a colony of cells. The general taxonomic group are best described as cyanobacteria. O cellulosic eukaryotic O prokaryotic diatomic

Answer 1

The third option is the correct answer, i.e. this photoautotrophic organism represents a colony of prokaryotic cells.

Oscillatoria is a cyanobacteria or blue-green algae. This alga is always in filamentous colonial form. Filaments are formed by prokaryotic cells arranged in a single row. This row of cells is covered by mucilage. The cells are considered are prokaryotes because they lack nuclei and any membrane-bound organelles. These two features are the main characteristics of any prokaryotic cell.

Explanation of the wrong options -

Cellulosic cells - Cellulose is present in the cell wall of this algae. But that doesn't mean that the cell is formed by cellulose only. The cell walls also contain pectin and mucilage. Inside the living protoplasm, there are many organic materials as well.

Eukaryotic cells - The cells of this algae don't have proper nuclei and any membrane-bound organelles. In a eukaryotic cell, the genetic material is contained in a nucleus and there are other membrane-bound organelles also. That's why this alga can't be a eukaryotic organism.

Diatomic cells - Each diatom is surrounded by a thick cell wall formed by silica, which is specifically called a frustule. This is the most important feature of a diatom. The cells of Oscillatoria don't have a frustule. That's why this alga is not a diatom.