Page 41 - Algae Anatomy, Biochemistry, and Biotechnology

24 Algae: Anatomy, Biochemistry, and Biotechnology

FIGURE 1.36 Unicell of Cryptomonas sp. (Bar: 6 mm.)

in the periplastidial space as starch granules. Sometimes an eyespot formed by spherical globules is
present inside the plastid, but it is not associated with the flagella. The cell is enclosed in a stiff,
proteinaceous periplast, made of polygonal plates. Most forms are photosynthetic, but heterotrophic
nutrition also occurs. The primary method of reproduction is simply by longitudinal cell division,
but sexual reproduction has recently been documented.

DINOPHYTA
The members of this division are typical unicellular flagellates (Figure 1.37) but can be also non-
flagellate, ameboid, coccoid, palmelloid, or filamentous. Dinoflagellates have two flagella with
independent beating pattern, one training and the other girdling that confers characteristic rotatory
swimming whirling motion. Flagella are apically inserted (desmokont type) or emerge from a
region close to the midpoint of the ventral side of the cell (dinokont type). Most dinoflagellates
are characterized by cell-covering components that lie beneath the cell membrane. Around the
cell there is a superficial layer of flat, polygonal vesicles, which can be empty or filled with cellulose

FIGURE 1.37 A marine dinoflagellate. (Bar: 30 mm.)