One is long and can be seen under a light microscope, but the other is very short without protruding from the cells. The function of flagella is to help euglena swim.
Structurally, cilia and flagella are indistinguishable. They both possess a central bundle of microtubules, called axoneme. There are motor proteins, called dynein, attached to Tubule A, one of the doublet. Microtubules are held together by cross-linking proteins. Each doublet is connected by Nexin protein. Photo credit: modified from LadyofHats on wiki. Euglena has a bright red eyespot, also called stigma.
It is made up of carotenoid pigment granules. The eyespot is not an actual eye; instead, it is more like a sunglass for a photoreceptor. The eyespot filters the sunlight and allows certain wavelengths of light to reach photoreceptors also called paraflagellar body.
Therefore, the eyespot can tell the euglena where the light source comes from. Paraflagellar body also called photoreceptor is a swelling structure at the base of the flagellum that is photosensitive. It is the photoreceptor that senses light. Paraflagellar body, together with an eyespot, is located close to the flagella; thus their proximity promotes light-guided directional movement.
Euglena also has chloroplasts throughout its body. Its chloroplasts contain chlorophyll a and b to produce sugar by photosynthesis; therefore, euglena can survive with light without eating. Euglena chloroplasts contain pyrenoids , a subcellular compartment inside chloroplasts. The photosynthesis produces paramylon , a starch-like carbohydrate. It serves as food storage and enables euglena to survive when light is not available.
Although euglena is able to make its own food by photosynthesis, it can also consume food via phagocytosis , a process to engulf food particles in a vacuole. A lysosome then fuses with a food vacuole, releasing enzymes to digest food. Euglena also has a contractile vacuole to collect and remove excess fluid from the cell. This flagellum originates from blepharoplast which lies at the base of the reservoir in the anterior end of the body.
It is made up of an axial elastic filament or axoneme, covered by a protoplasmic sheath. This flagellum consists of 2 central fibres enclosed in an inner membranous sheath , and 9 peripheral fibres in the periphery of the flagellum. Each central fibres are single made of one fibre each and the peripheral fibres are paired made of two sub-fibres each. The 9 peripheral fibres bear a double-row arms each, all pointing in the same direction. In the space between the peripheral and central fibres lie 9 secondary fibres.
This whole structure of the flagellum is continuous from the base of the flagellum to the tip while being enveloped by the outer sheath which is continuous with the plasma membrane. Their position inside the flagellum is just perfect for undulating actions as they could exert bending around the flagellar axis. Thus, not only causing forward movement of the body but also rotation and revolution of the body as well, all in alignment to the flagellar and the body axis.
The photosynthetic organism Euglena has the ATP synthase enzyme complex that highly interacts with the fatty acid molecules in the mitochondrial inner membrane, creating a curvature that is required to produce ATP more efficiently. The mitochondria of Euglena are present inside the blepharoplasts situated at the anterior end of the body. This post is written by Ronit Dey. Ronit Dey is a graduate in Zoology. Here, he has started sharing a lot of things that he has seen, learned, and researched so far related to Zoology.
You can read more about here at the About page. Euglena performs two different kinds of movements 1. Flagellar Movement 2. All euglena have chloroplasts and can make their own food by photosynthesis. They are not completely autotrophic though, euglena can also absorb food from their environment; euglena usually live in quiet ponds or puddles.
The flagellum is located on the anterior front end, and twirls in such a way as to pull the cell through the water. It is attached at an inward pocket called the reservoir.
Color the reservoir grey and the flagellum black. The Euglena is unique in that it is both heterotrophic must consume food and autotrophic can make its own food. Chloroplasts within the euglena trap sunlight that is used for photosynthesis, and can be seen as several rod like structures throughout the cell.
Color the chloroplasts green.
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