Main Groups of Micro-Organisms PDF

Main Groups of Micro- Organisms University of West Indies Dr. David Odulaja RECAP OF CLASS 1 Study of bacteria is? Study of viruses is? Study of parasites is? Study of fungi is? Bacteria Bacteria Bacteria have characteristic shapes: Spherical shaped bacteria are cal...

Main Groups of Micro- Organisms University of West Indies Dr. David Odulaja RECAP OF CLASS 1 Study of bacteria is? Study of viruses is? Study of parasites is? Study of fungi is? Bacteria Bacteria Bacteria have characteristic shapes: Spherical shaped bacteria are called Cocci Rod shaped bacteria are called Bacilli Comma shaped bacteria are called Vibrio Spiral shaped bacteria are called Spirochetes Cytoplasm The cytoplasm of a bacterial cell is a viscous watery solution or soft gel, containing a variety of organic and inorganic solutes, and numerous ribosomes. Bacterial cytoplasm have no mitochondria, or endoplasmic reticulum Cell wall The cell wall lies immediately external to the cytoplasmic membrane. It is 10-25 nm thick, strong and relatively rigid, though with some elasticity. Function of Capsules Flagella Bacterial flagella are long, thin filaments twisted spirally in open forms. VIRUSES DNA viruses examples RNA viruses examples Parasitology A parasite: : the study and medical implications of parasites that a living organism that acquires some of its basic nutritional requirements through its intimate contact with another living organism Parasites may be simple unicellular protozoa or complex metazoa Mycology All fungi are: eukaryotic organisms , have cell walls (chitin), filamentous structures, and produce spores; grow as saprophytes on decompose dead organic matter All fungi are:-Hetertrophic (requires organic carbon)-Saprophytic (living on dead organic material)-Parasitic (fungus living on another living organism  Fungi can exist as yeasts (unicellular organisms ) or as hyphae A mass of hyphae= mycelia ( multicellular filamentous structures, constituted by tubular cells with cell walls Dimorphic Fungi- Fungi which are able to convert from hyphal to yeast form dimorphic fungi -occur in both the yeast (at body temperature in tissue, in exudates, or if cultured @ 37° C) and mycelial forms (in nature or when cultured at 20° C)