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Questions and Answers
What percentage of the earth's atmosphere is composed of nitrogen gas?
What percentage of the earth's atmosphere is composed of nitrogen gas?
Which process involves converting nitrogen gas into a usable form for living organisms?
Which process involves converting nitrogen gas into a usable form for living organisms?
Which microorganisms are primarily involved in ammonification?
Which microorganisms are primarily involved in ammonification?
What is required for the process of nitrification to occur?
What is required for the process of nitrification to occur?
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What role do decomposers play in the nitrogen cycle?
What role do decomposers play in the nitrogen cycle?
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During which stage of the nitrogen cycle is ammonia converted into nitrates?
During which stage of the nitrogen cycle is ammonia converted into nitrates?
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Which of the following statements about nitrogen fixation is true?
Which of the following statements about nitrogen fixation is true?
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What is the primary source of nitrogen for green plants?
What is the primary source of nitrogen for green plants?
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What is the primary end product of nitrification that is most usable by plants?
What is the primary end product of nitrification that is most usable by plants?
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Which process involves the conversion of nitrates back to nitrogen gas?
Which process involves the conversion of nitrates back to nitrogen gas?
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What is the primary role of the bacterium's enzyme system in relation to the host plant?
What is the primary role of the bacterium's enzyme system in relation to the host plant?
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Which of the following is a method of biological nitrogen fixation?
Which of the following is a method of biological nitrogen fixation?
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What is the shape of free-living Rhizobia compared to nitrogen-fixing forms?
What is the shape of free-living Rhizobia compared to nitrogen-fixing forms?
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Which nitrogen-fixing bacteria are most closely associated with legumes?
Which nitrogen-fixing bacteria are most closely associated with legumes?
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Which of the following activities does Rhizobium perform while in the root nodules?
Which of the following activities does Rhizobium perform while in the root nodules?
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What is the energy requirement for the reduction of nitrogen gas to ammonia during biological nitrogen fixation?
What is the energy requirement for the reduction of nitrogen gas to ammonia during biological nitrogen fixation?
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What material is used to sterilize the work area during the experiment?
What material is used to sterilize the work area during the experiment?
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What is the purpose of washing the root nodule with antiseptic?
What is the purpose of washing the root nodule with antiseptic?
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Which bacteria are involved in the process of oxidizing ammonium ions to nitrites?
Which bacteria are involved in the process of oxidizing ammonium ions to nitrites?
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Which staining method is used to examine the bacteria after preparing the smear?
Which staining method is used to examine the bacteria after preparing the smear?
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What is the role of nitrogen-fixing bacteria in the nitrogen cycle?
What is the role of nitrogen-fixing bacteria in the nitrogen cycle?
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Which option correctly identifies both free-living and symbiotic nitrogen-fixing bacteria?
Which option correctly identifies both free-living and symbiotic nitrogen-fixing bacteria?
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What percentage of ethanol is used to treat the root nodule during the experiment?
What percentage of ethanol is used to treat the root nodule during the experiment?
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During what phase do Rhizobia exhibit different shapes such as T-Y-L-X-V?
During what phase do Rhizobia exhibit different shapes such as T-Y-L-X-V?
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Study Notes
Ecological and Environmental Microbiology - Env 231
- Nitrogen in the Air: Nitrogen is essential for life, but the atmospheric nitrogen (N2) form isn't usable by most living organisms.
- Nitrogen Fixation: This process converts atmospheric nitrogen gas into ammonia (NH3), a usable form for plants.
- The Nitrogen Cycle: A continuous process involving multiple steps that convert nitrogen gas to organic forms and back again. Decomposers and nitrogen bacteria play key roles.
- Nitrogen Fixation by Rhizobium: Rhizobium is a well-known nitrogen-fixing bacteria that forms symbiotic relationships with legumes (e.g., peas, beans).
- Nitrogen fixation methods: Atmospheric, industrial (Haber-Bosch), and biological (by bacteria).
- Biological Fixation (by Bacteria): Nitrogen-fixing bacteria fix around 60% of atmospheric nitrogen gas.
- Symbiotic Relationship (Rhizobium): Rhizobium bacteria infect legume roots, forming nodules. The plant provides nutrients, and the bacteria convert N2 into ammonia.
- Free-Living Nitrogen-Fixing Bacteria: Azotobacter and Clostridium are examples.
- Nitrogen-Fixing Bacteria Structure: Rhizobium bacteria can be bacilli, non-spore forming, motile, and aerobic
- Other Bacteria: Certain soil bacteria have roles in converting nitrogen compounds (ammonium ions to nitrites then to nitrates). Nitrifying bacteria (Nitrosomonas or Nitrobacter) involve in conversion of Nitrogen to a plant usable form.
- Denitrification: Denitrifying bacteria convert nitrates back into nitrogen gas, returning it to the atmosphere, thus completing the cycle.
- Experiment Aim: To determine and identify nitrogen-fixing bacteria using a microscope.
Experiment Details
- Materials: Root nodules, sterile water, Petri dish, sterile tongs, flame, Dettol, cotton, Ethanol.
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Methods:
- Clean the work area.
- Separate root nodules from the roots.
- Wash nodules with antiseptic.
- Put nodule in Ethanol for 30-60 seconds.
- Transfer to sterile water.
- Mash nodule in a Petri dish.
- Prepare a bacterial smear.
- Stain the bacteria using Gram stain.
- Examine the bacteria under the microscope.
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Description
Delve into the fascinating world of nitrogen in our environment with this quiz on Ecological and Environmental Microbiology. Learn about the nitrogen cycle, the vital role of nitrogen-fixing bacteria like Rhizobium, and various nitrogen fixation methods. Test your knowledge on how these processes are essential for sustaining life on Earth.
