Page 72 - Algae Anatomy, Biochemistry, and Biotechnology

Anatomy 55

FIGURE 2.24 Lorica of Strombomonas verrucosa.

The solid structure of the pellicle confers a very high degree of flexibility and resistance to the
cells. Our experience with E. gracilis allow us to say that this alga possesses one of the strongest
covering present in these microorganisms. A pressure of more than 2000 psi is necessary to break
the pellicular structure of this alga.

FLAGELLA AND ASSOCIATED STRUCTURES
Flagella can be defined as motile cylindrical appendages found in widely divergent cell types
throughout the plant and animal kingdom, which either move the cell through its environment or
move the environment relative to the cell.
Motile algal cell are typically biflagellate, although quadriflagellate types are commonly found
in green algae; it is generally believed that the latter have been derived from the former, and a
convincing example of this derivation is Polytomella agilis from Chlamydomonas. A triflagellate
type of zoospore such as that of Acrochaete wittrockii (Chlorophyceae, Chlorophyta) may have
originated from a quadriflagellate ancestor by reduction, whereas the few uniflagellate forms
are most likely descendant of biflagellated cells. Intermediate cases exist, which carry a short