Euglena is a genus of eukaryotes which are single celled flagellated. It is the most renowned and widely studied species of class Euglenoidea, the group containing 54 genera and more than 800 species. The home for the species of euglena are freshwater and saltwater. They are often abundantly found in the inland waters where they might be found blooming which might be sufficient for covering the ponds and rivers into greens. 

As they are photosynthetic protists, Euglena have a taxonomical trait that is somewhat debatable, and there’s a dilemma in placing the genus either in the phylum Euglenozoa or the phylum Euglenophyta of algae.

NOW LET US UNDERSTAND THE STRUCTURE OF EUGLENA:

Euglena can be characterized by an elongated cell (15–500 micrometers [1 micrometer = 10−6 meter], or 0.0006–0.02 inch) with one nucleus, extreme number of chlorophyll containing chloroplasts, a vacuole which can contract, an eye and one or more flagella.

STRUCTURE OF EUGLENA:

• Plasma membrane: It is a thin, semi-permeable membrane which surrounds the cytoplasm of the cell enclosing the contents.
• Cytoplasm: It is a jelly-like, watery substance inside the cell.
• Chloroplasts: These are the plastids that consist of chlorophyll that helps in absorbing light energy for photosynthesis.
• Contractile Vacuole: A structure that helps in removing excess water from the cell.
• Flagellum: A cellular lump formed by specialized microtubules that helps in movement of the cell.
• Eyespot: The area containing pigment granules that helps in the eyesight and detection of light. It is also called a stigma.
• Photoreceptor or Paraflagellar Body: This is a light-sensitive region that helps in detecting light and is located near the flagellum. It helps in phototaxis.
• Paramylon: It is a starchy carbohydrate which is made of glucose produced during photosynthesis. When photosynthesis is not possible it serves the food.
• Nucleus: A membrane bound structure containing DNA.
  • Nucleolus: A structure present in the nucleus that consists of RNA and helps in the production of ribosomal RNA for synthesizing ribosomes.
• Mitochondria: These are the organelles which provide energy to the cell.
• Ribosomes: It consists of RNA and proteins, as ribosomes help in protein assembly.
• Reservoir: The inward pocket present near the anterior of the cell where flagella arises and excess water is pulled out by the contraction of vacuoles.
• Golgi apparatus: Helps in manufacturing, storing, and shipping certain cellular molecules.
• Endoplasmic Reticulum: This extensively designed network of membranes is made of both regions with ribosomes (rough Endoplasmic Reticulum) and regions without ribosomes (smooth Endoplasmic Reticulum). It also helps in protein production.
• Lysosomes: The sacs of enzymes that help in digestion of cellular macromolecules hence detoxifying the cell.

 Species of Euglena shows organelles found both in plant and animal cells. They have flagella and do not consist of cell walls which are typical specifications of animal cells. Maximum species of Euglena do not consist chloroplasts and hence phagocytosis helps in ingestion of food. 

CLASSIFICATION OF EUGLENA:

DOMAIN: Eukaryota

KINGDOM: Protista

CLASS: Euglenoidea

PHYLUM: Euglena

FAMILY: EuglenAceae

SUPER PHYLUM: Discoba

ORDER: Euglenales

GENUS: Euglena

Euglenas were initially classified under Domain Eukarya, Kingdom Protista, and Phylum Euglenozoa. There was a huge dilemma over which euglena belonged to which kingdom. Hence, it is finally understood that Protista is not a natural way of grouping euglena. Finally, Euglena is classified in the Kingdom Excavata.

SOME FACTS ABOUT EUGLENA:

The body of euglena is green in color as there are rod-like structures called chloroplasts which are responsible for green color. Though the structure of the cell of euglena is different from other plant and animal cells as it does not have a cell wall made of cellulose. Euglena has a pellicle in its outermost cell membrane which maintains the elliptical shape.A very positive feature of euglena is its both autotrophic and heterotrophic. When there’s enough sunlight in the environment, euglena absorbs sunlight as the chloroplasts get activated and produces its own food through photosynthesis. When there is no abundant amount of sunlight in the environment, it becomes a heterotroph, which means it consumes other microorganisms such as amoeba, paramoecium and so on. 

Euglena has an ability of sucking extreme water through osmosis which may lead to bursting. These kinds of consequences can be prevented through the presence of special contractile vacuoles. The shape of the vacuole is star and present in the rear portion. It helps in excreting too much water from the euglena.

Euglena reproduce by the process called mitosis.In mitosis, the cell is divided into two equal halves, producing two new identical offspring. Reproduction will only take place if the atmospheric conditions are ideal for reproduction, which is warm temperature and sufficient food for the offspring and the parent as well.

CONCLUSION:

We came to know how the structure of euglena is and what suitable places for euglena to survive are. The classification of euglena let us know about the phylum, class, kingdom of euglena where it belongs. Euglena is an important structure of biology and for the students who are going to pursue more about plant physiology. We get to see euglena most of the monsoon season as it covers the lakes and ponds. This information about euglena may help you in the near future.