Describe the structural characteristics of both unicellular and multicellular blue-green algae, contrasting the properties of blue-green algae with those of true plants.
In their unicellular form, the Cyanophyta, or blue-green algae, are either rod- or sphere-shaped and can occur either singly or united by a gelatinous matrix into colonies. Blue-green algae can also exist as filamentous multicellular organisms, where some division of labor among the cells exists but where the individual cells retain a great deal of independent functions. All blue-green algae are photosynthetic, containing chlorophyll a in membrane-bound vesicles called thylakoids which are similar to the chromatophores found in photosynthetic bacteria. The thylakoids are not contained within chloroplasts. Blue-green algae also lack the large vacuoles found in the cells of plants.
