BIOL 336 Lecture 11: February 20th 2017
23 Feb 2017
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Document Summary
2 dissimilar flagella emerge at cell apex. Divided into two parts: apical: epitheca (or epicone, posterior: hypotheca (or hypocone) 2 dissimilar flagella emerge from pore between cingulum and sulcus (ventral) In all dinoflagellates: number, size and shapes of thecal plates used for taxonomy: flagella and motility. Transverse flagellum: ribbon shaped, lies in the cingulum, wraps around the cell (counterclockwise, as seen from cell apex, provides 50% swimming speed and rotation. Longitudinal flagellum: lies within the sulcus, extends beyond the cell body: position can change, provides 50% forward swimming speed and, plastids and photosynthesis steering. ~50% have plastids (other 50% are heterotrophic) Unusual organelle (found in many, more developed in heterotrophic dinos) Invagination of cell membrane where the flagella comes out. Not sure the function of it, believed to have something to do with excretion. Branched membrane sacs or tubules derived from invagination of cell membrane. Opens to the surface: vicinity of flagella. Function: excretion, osmoregulation and uptake process: trichocysts.
