the amoebas are single-celled protozoa.
They belong to the group of rhizopods, also called sarcodines.
Types of Amoebas
The amoebas can be from free life, diners or parasites.
Most are free-living and can be found in fresh and salt water.
Diners can live in the human body without causing harm, such as the Entamoeba gingivalis, which lives in the mouth and the Entamoeba coli, which inhabits the large intestine.
Among the parasites, the Entamoeba histolytica, found in the intestines of humans and which causes Amebiasis.
Amoeba Structure
The only cell that makes up an amoeba is flexible and without supporting structures. They have shapes and sizes ranging from 10 µm to 60 µm.
The cytoplasm is divided into more rigid outer ectoplasm and more fluid inner endoplasm. They have a contractile or pulsatile vacuole that controls the volume of water inside the cell. The core is central.
The amoeba can be naked or surrounded by a type of carapace, called a thecameba. This envelope is secreted by the amoeba's own cytoplasm.
Movements and food are guaranteed by the pseudopods. The presence of pseudopods is one of the main characteristics of amoebas.
Amoeba and pseudopods that help with movement and feeding
Feeding and Reproduction
Amoebas are heterotrophic beings and feed on bacteria, algae and other protozoa.
For food, amoebas use pseudopods that wrap the food around it and surround it in a food vacuole for digestion. This process is known as phagocytosis.
Learn more about Phagocytosis.
As for reproduction, amoebas are asexual and perform bipartition. In this process, the cell divides, by mitosis, and gives rise to two daughter cells, genetically identical to the mother cell.
Diseases caused by Amebas
The main disease caused by amoebas is Amebiasis.
Amoebiasis is an alteration in the functions of the intestines. About 10% of the world population is affected by this disease. In Brazil, the highest incidence occurs in the Amazon region.
Learn about the symptoms, transmission, treatment and prevention of Amebiasis.
Some free-living amoebae can cause illness in man. Free-living amoebae are found in soil, dust, air, contact lens solutions, rivers, swimming pools and lakes. In this case are granulomatous amoebic encephalitis (inflammation of the brain) and amoebic keratitis (chronic infection of the cornea).
Learn more about others Diseases caused by protozoa.
