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Chlamydomonas (/ ˌ k l æ m ɪ ˈ d ɒ m ə n ə s,-d ə ˈ m oʊ-/ KLAM-ih-DOM-ə-nəs, -də-MOH-) is a genus of green algae consisting of about 150 species [2] of unicellular flagellates, found in stagnant water and on damp soil, in freshwater, seawater, and even in snow as "snow algae". [3]
A flagellum (/ f l ə ˈ dʒ ɛ l əm /; pl.: flagella) (Latin for 'whip' or 'scourge') is a hair-like appendage that protrudes from certain plant and animal sperm cells, from fungal spores , and from a wide range of microorganisms to provide motility.
The eyespot apparatus (or stigma) is a photoreceptive organelle found in the flagellate or (motile) cells of green algae and other unicellular photosynthetic organisms such as euglenids. It allows the cells to sense light direction and intensity and respond to it, prompting the organism to either swim towards the light (positive phototaxis ...
The main function of the eyespot is the phototaxis, which consist of the movement (with the flagella) related to a light stimulus. [7] The phototaxis is crucial for the alga and allows for localization of the environment with optimal light conditions for photosynthesis. [8] Phototaxis can be positive or negative depending on the light intensity ...
The longitudinal flagellum is relatively conventional in appearance, with few or no hairs. It beats with only one or two periods to its wave. The flagella lie in surface grooves: the transverse one in the cingulum and the longitudinal one in the sulcus, although its distal portion projects freely behind the cell.
Flagella in eukaryotes are supported by microtubules in a characteristic arrangement, with nine fused pairs surrounding two central singlets. These arise from a basal body. In some flagellates, flagella direct food into a cytostome or mouth, where food is ingested. Flagella role in classifying eukaryotes.
Schematic drawing of Cafeteria roenbergensis (Heterokonta: Bicosoecida) with two unequal (heterokont) flagella: an anterior straminipilous (with tubular tripartite mastigonemes) and a posterior smooth A chrysomonad (Heterokonta: Chrysophyceae) under TEM, with a smooth flagellum (1) and a long flagellum covered with mastigonemes (3) Two cryptomonads (Cryptophyceae) under SEM.
These are often packed together to form two or more rods, which function in ingestion, and in Entosiphon form an extendable siphon. Most phagotrophic euglenids have two flagella, one leading and one trailing. The latter is used for gliding along the substrate. In some, such as Peranema, the leading flagellum is rigid and beats only at its tip.