Protista - Eukarya (Organisms: Amoebae) Part 01

Amoebas are eukaryotic organisms that walk in a crawling manner. In my previous post, I mention that organisms are into two groups, that is prokaryotes and eukaryotes cells. Eukaryotic cells are more organized than prokaryotes, which are found in bacteria and Archaea.

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• Structure
• Movement
• Classification
• Importance

Structure

Amoebas are eukaryotes with single cells like other eukaryotes with their cytoplasm and cellular content covered by a cell membrane. Amoeba has DNA packaged in a cellular compartment called the nucleus. They also have a structure called organelles which function in energy production and protein transportation. Organelles are common in Eukaryotes cells as they help in the transportation of protein.

The organelles (mitochondria) responsible for cellular energy generation are not found in some Amoebas because they are found in areas without oxygen. So organisms without mitochondria have organelles (hydrogenosomes or mitosomes) which are highly altered versions of the mitochondrion. An example of such an organism is the Entamoeba Histolytica and Mastigamoeba Balamuthi.

Movement

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Amoebas are like our cells and have a movement like the white blood cells. Amoeba moves using Pseudopodia which means false feet in the Latin language. These pseudopodia are formed by short-outward projections from the cytoplasm which help grip surfaces. Amoeba moves in a one-direction movement as the pseudopodium moves out along the surface in a contracted manner. The contraction movement pushes the cytoplasm to fill the expanding area as the adhesions are pulled up at the back end of the cell.

Amoebas have four types of pseudopodia: filopodia, Lobopodia, Rhizopoda, and Axopodia. Lobopodia is the most common which is blunt cytoplasmic projection, and its broad nature distinct it from filopodia(thin thread-like projections). The pseudopods are supported by the structure elements which aid in executing cell movements.

Pseudopodia which is used for movement in Amoeba can also be used for feeding. Some Amoeba uses pseudopodia to inject both solid and liquid food. Phagocytosis is the process of Amoeba ingesting solid materials with their pseudopodia. In the case of giant Amoeba, they gathered their pseudopodia to engulf their prey surrounding it with the cell membrane.

Thanks for reading, next post will be on the classification and importance of amoeba.