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Euglena reproduce asexually through binary fission, a form of cell division. Reproduction begins with the mitosis of the cell nucleus , followed by the division of the cell itself. Euglena divide longitudinally, beginning at the front end of the cell, with the duplication of flagellar processes, gullet and stigma.
A number of species exists where a chloroplast's absence was formerly marked with separate genera such as Astasia (colourless Euglena) and Hyalophacus (colourless Phacus). Due to the lack of a developed cytostome, these forms feed exclusively by osmotrophic absorption.
Euglena viridis is a freshwater, single cell, mixotroph microalgae bearing a secondary chloroplast. [1] Their chloroplast is bounded by three layers of membrane without a nucleomorph . [ 2 ] Normally, it is 40–65 μm long, slightly bigger than other well-known Euglena species: Euglena gracilis .
Euglena gracilis is a freshwater species of single-celled alga in the genus Euglena. It has secondary chloroplasts , and is a mixotroph able to feed by photosynthesis or phagocytosis . It has a highly flexible cell surface, allowing it to change shape from a thin cell up to 100 μm long to a sphere of approximately 20 μm.
For example, the algae Euglena and Dinobryon have chloroplasts for photosynthesis, like plants, but can also feed on organic matter and are motile, like animals. In 1860, John Hogg argued against the use of "protozoa", on the grounds that "naturalists are divided in opinion—and probably some will ever continue so—whether many of these ...
Euglenaceae show the most morphological diversity within the class Euglenophyceae. [3] They are mostly single-celled organisms, except for the genus Colacium.They are free-living or sometimes inhabiting the digestive tracts of animals. [1]
Schematic representation of a Euglena cell with red eyespot (9) Schematic representation of a Chlamydomonas cell with chloroplast eyespot (4). 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.
In some algae, such as Euglena, the plastids can be destroyed by certain chemicals or prolonged absence of light without otherwise affecting the cell: the plastids do not regenerate. Transport proteins called porins are found in the outer membranes of mitochondria and chloroplasts and are also found in bacterial cell membranes. [67] [68] [69]