Protozoa Study Resources

PROTOZOA Protozoa is includes protists eukaryotic. Protozoa are distinguished from prokaryotes because of their larger size and the cells are eukaryotic. Protozoa do not contain chlorophyll but they can move actively and do not have cell walls as well as distinguished from slime molds because they cannot form fruiting bodies. Habitat of Protozoa Protozoa generally live freely and are found in oceans, water environments fresh, or land. Some species are parasitic, living on organisms host. Hosts for parasitic protozoa can be simple organisms such as algae, to complex vertebrates, including humans. A number of species can grow in the soil or on the surface of vegetation. All protozoa require high humidity in any habitat. Several types of marine protozoa are part of zooplankton. Other marine protozoa live on the sea floor. Species that live in fresh water can be in lakes, rivers, ponds, or puddles. Protozoa also can found as a parasite that lives in the intestines or in the rumen ruminant animals. Morphology of Protozoa Protozoa do not have cell walls and do not contain cellulose or chitin. Most protozoa have specific form which is characterized by the flexibility of the ectoplasm present in cell membrane. Several types of protozoa such as Foraminifera have very hard exoskeleton composed of Si and Ca. Some protozoa like Difflugia, can bind mineral particles to form a skeleton tough outside. All protozoa have contractile vacuoles. Vacuoles may play a role as a pump to remove excess water from cells, or to regulate osmotic pressure. The number and location of contractile vacuoles differs from person to person species. Protozoa can exist in vegetative form (trophozoite), or form breaks are called cysts. Protozoa under unfavorable conditions can form cysts to maintain its life. When the cyst is located Under favorable conditions, it will germinate into a cell vegetative vegetative. Protozoa are single cells, which can move in a unique way uses pseudopodia (false legs), flagella or cilia, but there are some unable to move actively. Physiology of Protozoa Protozoa are generally aerobic, nonphotosynthetic, but some are protozoa can live in anaerobic environments (eg in canals human or ruminant digestion). Aerobic protozoa have mitochondria which contain enzymes for aerobic metabolism, and for produces ATP through the process of transferring electrons and hydrogen atoms to oxygen. Protozoa generally obtain food by preying on organisms other (bacteria) or organic particles, either by phagocytosis or pinocytosis. Protozoa that live in water environments, then oxygen and water as well as other molecules Small molecules can diffuse through cell membranes. Macromolecular compounds which cannot diffuse through the membrane, can enter the cell indirectly pinocytosis. Fluid droplets enter through channels in the cell membrane, when The full channel then enters the membrane it binds to vacuole. Small vacuoles are formed, then carried to the interior of the cell, Next, the molecules in the vacuole are moved to the cytoplasm. can reproduce sexually and asexually. By Asexual protozoa can divide into 2 daughter cells (binary). Sexual reproduction Protozoa Reproduction Protozoa can be done through conjugation, autogamy, tccytogamy. Protozoa that have more than one habitat or host can has several ways of reproduction. For example species Plasmodium can carry out schizogony asexually in host cells humans, but in mosquito host cells, reproduction can occur sexual. Protozoa generally exist in diploid form. Protozoa generally have the ability to repair their cells damaged or cut. Some ciliates can repair their cells10% of the original cell volume remains as long as the cell nucleus remains.