General characteristics and classification of protozoa. | Bsc biology 1st semester mgsu university. скачать в хорошем качестве

General characteristics and classification of protozoa. | Bsc biology 1st semester mgsu university.

Notes pdf link:- https://drive.google.com/file/d/18njn... Protozoa, also known as single-celled eukaryotes, are microscopic organisms that lack the complex tissues and organs found in multicellular organisms. They are classified under the kingdom Protista and are characterized by several key features: *General Characteristics:* *Unicellular:* They consist of a single cell that performs all the functions necessary for survival. *Eukaryotic:* They have a nucleus containing genetic material (DNA) and other membrane-bound organelles. *Microscopic:* They are generally too small to be seen with the naked eye and require a microscope for observation. *Heterotrophic:* They obtain their food by ingesting other organisms or organic matter. *Diverse:* Protozoa exhibit a wide range of shapes, sizes, and lifestyles. *Classification:* Protozoa are classified into four major subphyla based on their mode of locomotion and other characteristics: *1. Sarcomastigophora:* *Locomotion:* These protozoa move using pseudopodia (false feet) or flagella (whip-like structures). *Examples:* Amoeba, Euglena, Trypanosoma *2. Sporozoa:* *Locomotion:* These protozoa are non-motile in their adult stage and reproduce through spores. *Examples:* Plasmodium (causes malaria), Toxoplasma gondii *3. Cnidospora:* *Locomotion:* These protozoa are also non-motile and are characterized by the presence of cnidocysts (stinging cells). *Examples:* Myxosporidia, Microsporidia *4. Ciliophora:* *Locomotion:* These protozoa move using cilia (hair-like structures). *Examples:* Paramecium, Stentor *Details about each subphylum:* *1. Sarcomastigophora:* *Pseudopodia:* These are temporary extensions of the cell membrane that allow the protozoan to engulf food particles. *Flagella:* These are long, whip-like structures that propel the protozoan through its environment. *Examples:* *Amoeba:* A common freshwater protozoan that moves using pseudopodia and engulfs food by phagocytosis. *Euglena:* A photosynthetic protozoan that possesses both plant-like and animal-like characteristics. It can move using a flagellum and can also produce its own food through photosynthesis. *Trypanosoma:* A parasitic protozoan that is transmitted by insects and causes diseases such as African trypanosomiasis (sleeping sickness) and Chagas disease. *2. Sporozoa:* *Spores:* These are resistant structures that contain the protozoan's genetic material and are capable of surviving harsh conditions. *Examples:* *Plasmodium:* The causative agent of malaria, a serious disease that is transmitted by mosquitoes. It has a complex life cycle that involves both sexual and asexual reproduction. *Toxoplasma gondii:* A parasitic protozoan that can infect a variety of animals, including humans. It is most commonly transmitted through undercooked meat or contact with cat feces. *3. Cnidospora:* *Cnidocysts:* These specialized cells contain a stinging apparatus that is used to capture prey or defend against predators. *Examples:* *Myxosporidia:* Parasitic protozoa that infect fish and other aquatic animals. *Microsporidia:* Obligate intracellular parasites that infect a wide range of hosts, including humans. *4. Ciliophora:* *Cilia:* These tiny hair-like structures cover the surface of the protozoan and help it move and capture food. *Examples:* *Paramecium:* A common freshwater protozoan that is characterized by its slipper-shaped body and cilia. It is a predator that feeds on bacteria and other small organisms. *Stentor:* A large, trumpet-shaped protozoan that is often found in ponds and lakes. It is a filter feeder that uses its cilia to sweep food particles into its mouth.