of Classification Cellular Organism (according to cell structure)
Cellular Organism
Have nuclear membrane and membrane bound organells? Yes No
not free-living organisms
Eucaryotes
Procaryotes: bacteria
Virus
Protists: Fungi, Algae, protozoa Plant: seed plants, mosses Animal: vertabrates and invertabrates
Eubacteria: Gram-positive bacteria Gram-negative bacteria Non-gram bacteria: Actinomycetes Cynaobacteria
Archaebacteria: methanogen Halogen Thermoacidophiles
Classification of Cellular Organism (according to cell structure)
Cellular Organism
Have nuclear membrane and membrane bound organells? Yes No
not free-living organisms
Eucaryotes
Procaryotes: bacteria
Virus
Protists: Fungi, Algae, protozoa Plant: seed plants, ferns, mosses Animal: vertabrates and invertabrates
Eubacteria: Gram-positive bacteria Gram-negative bacteria Non-gram bacteria Actinomycetes Cynaobacteria
Archaebateria: methanogen Halogen Thermoacidophiles
Procaryote
Procaryotes have no membrane around the cell genetic information and no membrane-bound organelles
Bacteria: E. Coli, Rhodospirillum sp. Size: 0.5-3m. Grow rapidly, double times: 0.5 hour and several hours. Utilize carbon sources: carbohydrates, hydrocarbon, protein and CO2.
Picture courtesy of http://micro.magnet.fsu.edu/cells/procaryotes/images/procaryote.jpg
Procaryote Cell Structure
Nuclear region There is no membrane around the nuclear region containing genetic materials such as chromosomes and DNA (deoxyribonucleic acid). Chromosomes: A chromosome is, a very long, continuous piece of DNA, which contains many genes, regulatory elements and other intervening nucleotide sequences. The DNA which carries genetic information in biological cells is normally packaged in the chromosomes.
http://micro.magnet.fsu.edu/cells/procaryotes/images/procaryote.jpg
Procaryote Cell Structure
Cytoplasm In cytoplasm, there are some visible structures: - ribosomes: sites of protein synthesis, 10,000 per cell, 10 -20 nm, 63% RNA and 37% protein. - storage granules: source of key metabolites, containing polysaccharides, lipids and sulfur granules. Sizes vary between 0.5-1 m. - Plasmids: DNA molecules separate from the chromosomal DNA and capable of autonomous replication. Usually occur in bacteria. e.g E.coli Application in Genetic Engineering.
http://micro.magnet.fsu.edu/cells/procaryotes/images/procaryote.jpg
Procaryote Cell Structure
Cytoplasmic membrane - The cytoplasm is surrounded by a membrane called cytoplasmic membrane. - The cytoplasmic membrane contains 50% protein, 30% lipids and 20% carbohydrates.
http://micro.magnet.fsu.edu/cells/procaryotes/images/procaryote.jpg
Procaryote Cell Structure
Cell wall - Eubacteria cell walls contain lipids & peptidoglycan which is a complex polysaccharide with amino acids and forms a structure somewhat like chain-link fence. - Archaebacteria walls cell do not have peptidoglycan. Outer membrane: Some bacteria (gram negative cells) have. - To retain important cellular compounds and - To exclude undesirable compounds in the environment.
http://micro.magnet.fsu.edu/cells/procaryotes/images/procaryote.jpg
Procaryote Cell Structure
Capsule: Extracellular products can adhere to or become incorporated within the surface of the cell. Certain cells have a coating outside the cell wall called capsule. It contains polysaccharides or polypeptide and forms biofilm response to environmental challenges. Flagellum: is for cell motion. Pilus (Pili, pl.) A pilus is a hairlike structure on the surface of a cell. Pili enable the transfer of plasmids between the bacteria. An exchanged plasmid can add new functions to a bacterium, e.g., an antibiotic resistance.
Procaryotes
Procaryotes include - Eubacteria - Archaebacteria
Eubacteria
Cell chemistry of eubacteria is similar to eucaryotes. Classification
Gram stain: Hans Christian Gram in 1884 developed the technique of gram stain which has been used to classify the eubacteria. Gram staining procedure: Fixing the cells by heating Dye with crystal violet stain purple Iodine and ethanol are added
a. Gram-negative: The cells are colorless after Gram staining procedure.
Gram-negative organisms will be counterstained with safranin and appear red or pink. Such cells have outer membrane supported by peptidoglycan e.g. E. coli.
b. Gram-positive: the cells remain purple after gram staining and
counterstaining procedures. Such cells have no outer membrane but with a rigid cell wall and thick peptidoglycan layer, e.g. B. subtilis.
Eubacteria
Other types of eubacteria:
Non gram bacteria: some bac...