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Beijerinck
- opinion of atmospheric nitrogen essential for plant growth;
- bacteria from nodules
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importance of nitrogen metabolism
N - essential element of organic compounds, including amino acids
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nitrogen fixation
trapping of nitrogen gas from atmosphere and its incorporation in organic compounds
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two types of microbes accomplishes nitrogen fixation.
- -free-living microbes
- -symbiotic microbes
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free living nitrogen fixers includes these species.
Azotobacter, Beijerinckia, & Clostridum and cyanobacteria (Nostoc & Anabaena)
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symbiotic nitrogen-fixers includes these species.
- Rhizobium and Bradyrhizobium
- -live in nodules on roots of legume plants
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symbiotic relationship between microbes and plants...
- complex; involves chemical attraction between bacterium and cells of plant root, binding to plant root, curling and branching of rootlets, and entry of bacteria into root hairs
- -infection thread develops and tumorlike growth (nodule) and bacter aumme distorted forms (bacteriods)
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bacteroids
bacteria that's distorted form in the nodules
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Bacteria that started a symbiotic relationship...
cannot live independently
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nitrification
ammonia deposited in soil and converted to valuable nitrate ions thru this process
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steps of nitrification
- 1. bacter, Nitrosomonas, convert ammonia to nitrite ions
- 2. nitrite ions converted by Nitrobacter to nitrate ions, which are relished by plants for making their organic materials
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nitrification occurs under ..
aerobic conditions and used by microbes as energy-yielding process
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denitrification
some species of microbes break down nitrate ions and produce nitrogen gas, giving atmosphere
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ruminants
grazing animals
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Cheese manufactured from milk in 3 steps.
- 1. curd formation
- 2. curd treatment
- 3. curd ripening
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Bacillus thuringiensis
a bacterial insecticides
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baculovirus
- type of virus having high affinity for insect tissues.
- -gene cloned from cells of scorpion which have toxin that paralyzes larvae of moths.
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