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25 Cards in this Set
- Front
- Back
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Compare Prokaryotes vs Eukaryotes.
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Prokaryotes are devoid of membrane bound organelles such as nuclei, mitochondria, chloroplasts, golgi vesicles; has a single circular chromosome; peptidoglycan.
Eukaryotes have true nuclei bounded by nuclear envelopes, several linear chromosomes, and no peptidoglycan. |
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What are the 3 bacterial divisions?
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Gracilicutes (Gram -), Firmicutes (Gram +), and Mollicutes (no cell wall)
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What morphology makes up the majority of Bacteria?
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Rods
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What makes up the components of the cell wall and what is the function?
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Component responsible for strength is peptidoglycan; function-rigid framework, protects cell from environmental stress
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Compare Gram + and Gram -.
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Gram + is a thick-walled cell with peptidoglycan bonded to polysaccharides and antigenic compounds.
Gram - is thinner walled composed of lipopolysaccharide, phospholipid, protein and peptidoglycan. More bacteria are in this group. |
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How does a bacteria's reproduction enhance its survival?
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Reproduces by binary fission causing rapid division and plasmids enhances resistance against unfavorable environments and antibiotics. Some produce endospores (only Bacillus)
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How does a bacteria enter a plant and how is it dispersed?
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Enters plant through wounds or natural openings. Dispersed through splashing water, man, aerosols, and insects.
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What are the phases in a bacterial pathogen's life cycle?
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1) pathogenic phase
2) epiphytic or resident phase--population increase on healthy plant tissue 3) survival stage (hypobiotic cells)--lots of cells die but some live through unfavorable condition in protected positions such as substomatal cavities, lumens of trichomes, buds, flowers |
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How do you identify phytopathogenic bacteria?
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Gram stain
Biochemical and physiological properties--not morphology Fatty acid profiles of cell walls RFLP Serological methods--use of antibodies |
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What is the procedure and results for a Gram stain?
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procedure used for identification of bacteria in which crystal violet stain, Gram's iodine, ethyl alcohol and safranin stain are applied in succession to cells of the bacteria
Gram + retains crystal violet Gram - crystal violet removed, pink or red |
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What are the biochemical and physiological properties that can be tested to identify bacteria?
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Grows anaerobic or aerobic
Grows at 40C Fluorescence on King's B Agar Yellow colonies on Yeast Dextrose Agar Production of urease Utilized arginine or betaine |
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What are some symptoms of plant pathogenic bacteria?
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Wilts, necrotic spots, hypertrophy, malformation, yellows, blight, leaf scorch
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What are signs of bacteria?
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streaming, ooze
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What is a Mollicute?
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one of a group of prokaryotic organisms bounded by flexuous membranes and lacking cell walls (phytoplasma and spiroplasma)
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What is EPS?
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Extracellular PolySaccharides; sugar polymers that contribute to the slimy appearance of bacteria probably promote colonization of plant tissues and disease development in bacteria
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What does pathovar refer to?
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a subdivision of a plant pathogenic bacterial species defined by host range; pathovar for bacteria is equivalent to forma specialis for fungi
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What are the functions of the outer membrane for Gram - bacteria?
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1) Provide channels for passive diffusion of nutrients or hydrophillic solutes
2) Permeability barrier to antibiotics, detergents, and other toxic substances 3) Provides receptor sites for bacteriophage and beactericins 4) Facillitates the formation and maintenance of mating pairs during conjugation 5) Endows hydrophilicity to cell surface |
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What is a flagella?
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hairlike, whiplike, or tinsel-like appendage of a motile cell, bacterium or zoospore that provides locomotion
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What is a plasmid?
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a circular, self-replicating hereditary element that is not part of a chromosome; plasmids are used in recombinant DNA experiments as acceptors and vectors of foreign DNA
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What is binary fission?
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a type of asexual reproduction in which two cells, usually of similar size and shape, are formed by the growth and division of one cell
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What is a monotrichous flagella?
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a single flagella coming out
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What is amphitrichous?
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two flagella, one from each end
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What is lophotrichous?
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several flagella coming out of one or both ends
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What is peritrichous?
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flagella coming out from all around the bacterium
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Citrus canker is vectored by what insect?
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citrus leaf miner
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