Cell StructureM212Ch4

Cell StructureM212Ch4 - Cell Structure Chapter 4 Living...

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Cell Structure Chapter 4 Living Organisms are classified according to the types of cells they have; each Kingdom of living organisms has different and unique cellular structures. : NON-Cellular parasites that do not have metabolic activities outside their host cells. Prokaryotic cells: Bacteria, Blue-Green algae, and the Archaea Microscopic organisms with cell walls, single circular chromosomes, frequently with flagella or cilia Secrete cell walls outside their cell membranes Some are photosynthetic or chemosynthetic autotrophs; others have heterotophic metabolisms, living as saprophytes or parasites. Archaea: Very tiny cells, often forming spores, with rigid cell walls that never contain PDG. Have a single circular chromosome, reproduce by binary fission, lack organelles, and live in extreme environments. May be either chemosynthetic or photosynthetic autotrophs. Blue-Green Algae: photosynthetic organisms found primarily in aquatic or marine environments, Have cell walls of chitin or other carbohydrates, important source of atmospheric Oxygen. Primary nitrogen fixers in marine and aquatic environments. High numbers are used to indicate high nitrogen run-off in fresh water streams. Kingdom: Monera Includes the true Bacteria and Cyanobacteria Bacteria: Very small unicellular or colonial organisms (0.2-2.0 nanometers). Have cell walls containing peptidoglycan, (PDG), have a single circular chromosome, lack membrane bound organelles, reproduce by binary fission. May have flagella, cilia, pili, capsules. Bacterial Cell Morphology and Arrangement: There are three common cell shapes or morphologies in Bacteria: Coccus: spherical cells that may be arranged as Diplococci, Tetrads, Streptococci, and Staphylococci. Cocci are never freely motile. Bacillus: cylindrical cells of varying lengths that may be arranged as : Random (motile cells); Streptobacillus, which are chains of bacilli; Coccobaccilli which are very tiny, oval bacilli that are always motile, with random arrangement. May be either motile or nonmotile. Often are spore formers. Spirilli: helical, wormlike or spiral shaped cells that are always motile; Spirochetes have axial filaments that enable rapid swimming with a corkscrew motion. All spirilli are motile
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Understand the difference between morphology and arrangement of cells BACTERIAL STRUCTURES Cell Wall Structure: Gram + cells have several layers of peptidoglycan, (PDG), cross-linked with teichoic acid and amino acid chains, NAM & NAG layers comprise the peptidoglycan. Gram – cells have both an inner and an outer plasma membrane, sandwiching a thin cell wall of PDG between the two membrane layers. Lack teichoic acid. Capsules:
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Cell StructureM212Ch4 - Cell Structure Chapter 4 Living...

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