Amoeba - The Structure And Movement Of The Amoeba, Unicellular Animal

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Amoeba - The Structure And Movement Of The Amoeba, Unicellular Animal
Amoeba - The Structure And Movement Of The Amoeba, Unicellular Animal

Video: Amoeba - The Structure And Movement Of The Amoeba, Unicellular Animal

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Video: What is An Amoeba | Biology | 2023, February

Last updated 1 March 2020 at 01:19

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Amoeba is a representative of the simplest unicellular animals. A free-living protozoan cell is able to move independently, feed, defend itself from enemies and survive in an unfavorable environment.

As part of the subclass "Roots" they belong to the class "Sarcodes".

The rhizome is represented by a wide variety of forms, among which there are three orders:

  1. naked;
  2. conchial;
  3. foraminifera.

The presence of a unifying feature - pseudopods, allows shells and foraminifera to move in the same way as an amoeba.

Radiolarians with a skeleton are sometimes referred to marine amoebae, although according to the classification they belong to another subclass of sarcode.

For medical practice, of interest are naked (ordinary) amoebas, in the structure of which there is no skeleton or shells. They live naked in both fresh and salt waters. The primitiveness of the organization of this organism is reflected in its specific name “Proteus” (“Proteus” means simple, although there is an interpretation of this name, referring to the ancient Greek god Proteus).

There are more than 100 species of Proteus, among them 6 species are described that are found in different parts of the human body:

  1. in the mouth;
  2. in the small and large intestine;
  3. in the cavity organs;
  4. in the lungs.


  • 1 Building
  • 2 Moving and feeding
  • 3 Role in biocenoses

    3.1 Similar articles



All proteas consist of one cell, the body of which is covered with a thin cytoplasmic membrane. The membrane protects a dense transparent ectoplasm, behind which is a jelly-like endoplasm. The endoplasm contains the bulk of the amoeba, including the vesicular nucleus. The nucleus is usually one, but there are also multinuclear species of organisms.

Proteus breathe with the whole body, waste products can be removed through the surface of the body, as well as through a specially formed vacuole.

Protozoa do not have sense organs, but they are able to hide from sunlight, are sensitive to chemical irritants and mechanical stress.

When unfavorable living conditions occur, the proteas form a cyst: the shape of the amoeba is rounded, and a protective shell forms on the surface. The processes inside the cell slow down until the onset of favorable times.

The structural features of the amoeba allow the animal organism to form cytoplasmic outgrowths, which have various names:

  • pseudopodia;
  • rhizomes;
  • pseudopods.

Moving and feeding


Roots provide the movement of the unicellular amoeba and the capture of the detected food. Regardless of the habitat, the amoeba-like movement consists in the protrusion of the rhizome in a certain direction and the subsequent overflow of the cytoplasm into the cell. Then the pseudopodia are re-formed elsewhere. There is a constant imperceptible overflow of the body in search of food. This method of movement does not allow proteins to have a fixed body shape.

In the variety of forms taken by proteas in motion, there are up to 8 types. The characteristics of the types are determined by the shape of the cell and the type of branching of pseudopodia during movement.

Proteas are omnivorous, feeding on by phagocytosis. Food for this heterotroph can be:

  • bacteria;
  • unicellular algae;
  • small protozoa.

The feeding process begins in motion as soon as the animal detects a potential prey nearby. The body of the simplest forms several pseudopodia, which surround the found object and form a closed cavity.

Digestive juice is released into the formed area from the cytoplasm - a digestive vacuole is formed. After the absorption of nutrients, undigested food debris is thrown out.

Role in biocenoses


For billions of years, protozoa have been actively involved in the formation of the Earth's biosphere, being a necessary consumer in the food chain of various biocenoses.

The amoeba's ability to move independently allows it to regulate the number of bacteria and pathogens that it feeds on. Biocenoses of sewage silt deposits, peat and boggy soils, fresh and sea waters are impossible without the participation of the simplest organisms.

Even the pathogenic dysentery amoeba in the intestinal biocenosis does not harm the healthy host organism, feeding on a variety of bacteria. And only organic lesions of the intestinal mucosa allow it to move into the circulatory system and switch to feeding on erythrocytes.

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