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GENERAL PROTOZOOLOGY. By. Dr. Emad AbdElhameed Morad. Lecturer of Medical Microbiology and Immunology. Protozoa are. Unicellular organisms. Structurally equivalent to a single cell. But, functionally, equal to a whole animal as it can perform all functions of life.
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GENERAL PROTOZOOLOGY By Dr. Emad AbdElhameed Morad Lecturer of Medical Microbiology and Immunology
Protozoa are • Unicellular organisms. • Structurally equivalent to a single cell. • But, functionally, equal to a whole animal as it can perform all functions of life. • Each cell is formed of a mass of protoplasm which is differentiated into: Cytoplasm Nucleus
Cytoplasm • Cytoplasm is differentiated into ectoplasm and endoplasm. • Protection from the surrounding environment. • Locomotion: motility of the cell may occur by pseudopodia, cilia and flagellae. Outer thin hyaline layer Ectoplasm
Nutrition by absorption of nutrients or ingestion of solid particles by the help of pseudopodia or cytosome. • Respiration through diffusion of gases (aerobic and anaerobic). • Excretion through diffusion through the body or by excretory vacuoles.
Inner granular layer Endoplasm • Food vacuoles: for digestion of food. • Excretory vacuoles: discharging waste products to exterior. • Volutin granules: stored food in the form of carbohydrates (glycogen vacuoles) or protein (chromatoid bodies).
Nucleus • Made of nuclear membrane and chromatin which represent the genetic material of the cell (DNA or RNA). • The chromatin is present in a single mass called karyosome and also distributed on the inner surface of nuclear membrane (peripheral chromatin). • In some protozoa, chromatin is present diffusely through out the nucleus.
Reproduction • Asexual: • Simple division of the nucleus and cytoplasm into two parts (binary fission) or several parts (multiple fission). • Sexual: • Formation of male and female gametes by meiosis and their union to form zygote.
Classification • According to the organs of locomotion: • Class rhizopoda: • Move by pseudopodia (false legs). • Example: amoeba.
Class ciliates: • Move by cilia which are small thin filaments found on the entire surface of the cell. • Example: Balantidium coli.
Class Flagellates: • Move by flagellae which are thin whip like filaments that arise from inside the cell. • According the habitat: • Intestinal: such as Giardia lamblia. • Urogenital: such as Trichomonas vaginalis. • Blood: such as leishmaniaand trypanosoma.
Class sporoza: • Move by gliding. • Examples: • Plasmodium: cause malaria. • Coccidia: cause diseases such as toxoplasmosis.