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Questions and Answers
Plants require large quantities of which element for optimal growth?
Plants require large quantities of which element for optimal growth?
- Potassium
- Sulfur
- Nitrogen (correct)
- Phosphorus
Which of the following nitrogen forms can plants directly utilize from the soil?
Which of the following nitrogen forms can plants directly utilize from the soil?
- NO₂⁻
- R-NH₂
- N₂
- NO₃⁻ and NH₄⁺ (correct)
What is the primary function of the Haber-Bosch process?
What is the primary function of the Haber-Bosch process?
- To enhance nitrogen fixation in root nodules.
- To produce organic nitrogen compounds.
- To extract nitrogen directly from the soil.
- To convert atmospheric nitrogen into a usable form for plants. (correct)
Which environmental conditions are essential for the Haber-Bosch process to efficiently convert nitrogen and hydrogen into ammonia?
Which environmental conditions are essential for the Haber-Bosch process to efficiently convert nitrogen and hydrogen into ammonia?
What is the role of nitrogenase in biological nitrogen fixation?
What is the role of nitrogenase in biological nitrogen fixation?
Which of the following organisms are known for forming symbiotic relationships with plants to facilitate nitrogen fixation?
Which of the following organisms are known for forming symbiotic relationships with plants to facilitate nitrogen fixation?
What is the term for bacteria and archaea capable of fixing atmospheric nitrogen?
What is the term for bacteria and archaea capable of fixing atmospheric nitrogen?
In root nodule symbiosis, what is the origin of the symbiosome membrane that surrounds the bacteria?
In root nodule symbiosis, what is the origin of the symbiosome membrane that surrounds the bacteria?
What is the role of the 'infection thread' in the context of root nodule formation?
What is the role of the 'infection thread' in the context of root nodule formation?
What is the arrangement called when describing root nodule symbiosis?
What is the arrangement called when describing root nodule symbiosis?
How does the alteration of root architecture aid plants in phosphorus acquisition?
How does the alteration of root architecture aid plants in phosphorus acquisition?
What is the primary environmental factor that influences the availability of inorganic phosphates in the soil?
What is the primary environmental factor that influences the availability of inorganic phosphates in the soil?
Which of the following elements is described as not entering the atmosphere during its biogeochemical cycle?
Which of the following elements is described as not entering the atmosphere during its biogeochemical cycle?
What role do decomposers play in the phosphorus cycle?
What role do decomposers play in the phosphorus cycle?
Why is the Haber-Bosch process considered an energy-demanding process?
Why is the Haber-Bosch process considered an energy-demanding process?
What are the products of the reaction N₂ + 3 H₂?
What are the products of the reaction N₂ + 3 H₂?
What is the term for the process where ammonium is converted into nitrite and then into nitrate in the soil?
What is the term for the process where ammonium is converted into nitrite and then into nitrate in the soil?
What is the role of cyanobacteria in biological nitrogen fixation?
What is the role of cyanobacteria in biological nitrogen fixation?
What is the consequence of a single bacterium being endocytosed into a plant cell during root nodule symbiosis?
What is the consequence of a single bacterium being endocytosed into a plant cell during root nodule symbiosis?
What term describes the unique root organ designed to support endosymbiotic rhizobia and nitrogen fixation?
What term describes the unique root organ designed to support endosymbiotic rhizobia and nitrogen fixation?
Flashcards
Nitrogen in Plants
Nitrogen in Plants
The most abundant mineral element in plants, essential for optimal growth.
Nitrogen Forms for Plants
Nitrogen Forms for Plants
Plants primarily obtain nitrogen from the soil in the forms of nitrate (NO3-) and ammonium (NH4+).
Nitrogen Fixation
Nitrogen Fixation
The conversion of atmospheric nitrogen (N2) into ammonia (NH4+), a form usable by plants.
Diazotrophs
Diazotrophs
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Nitrification
Nitrification
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Root Nodule
Root Nodule
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Plant Phosphorus
Plant Phosphorus
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Phosphorus Forms
Phosphorus Forms
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Root Nodule Symbiosis
Root Nodule Symbiosis
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Root nodule symbiosis
Root nodule symbiosis
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Study Notes
- Nitrogen is the most abundant mineral element in plants.
- Carbon, hydrogen, and oxygen are the most abundant elements in a plant.
- Optimal plant growth requires 20-50 g of nitrogen per kg of harvested product.
Inorganic Forms of Nitrogen
- Inorganic forms of nitrogen exist in nature.
- Plants cannot directly use N2, which is abundant in the air.
Nitrogen Uptake from Soil
- N Fixation converts N2 into NH4+.
- Ammonium and nitrate are available for plant use.
- Nitrification converts NH4+ to NO2- and then to NO3-.
Nitrogen Fixation
- Nitrogen fixation is the production of NH4+ from N2.
Industrial Nitrogen Fixation
- Haber-Bosch process produces nitrogenous fertilizers.
- These fertilizers significantly increased agricultural yields in the 20th century.
- The Haber-Bosch process requires high pressure (~300 bar) and temperature (~500 °C).
- The process is extremely energy-demanding.
Biological Nitrogen Fixation
- Diazotrophs (prokaryotes) fix nitrogen using nitrogenase.
- Diazotrophs include nitrogen-fixing bacteria and archaea.
Biological Nitrogen Fixation Types
Free-living in the Soil
- Cyanobacteria are photosynthetic nitrogen-fixing bacteria.
Symbiotic Inside Plant Roots
- Occurs in root nodules.
- Most plants forming nitrogen-fixing nodules are legumes.
- Root nodule symbiosis is mutually beneficial.
- A bacterium is endocytosed into the plant cell, with the symbiosome membrane originating from the plant.
- Bacteria divides within the cell, and symbiosomes also divide to generate more. -Rhizobium bacteria contact root hairs in soil. -Infection causes root hair curling due to chemical secretion. -An infection thread carries bacteria into the root cortex.
Nodulation
- Nodulation is the process of nodule development. -Formation of an infection thread allows Rhizobium bacteria to penetrate. -Bacteroids form within vesicles (Symbiosome). -Root cells grow around the bacteroid, creating a nodule. -Vascular tissues develop within the nodule.
Phosphorus in Plants
- Phosphorus is the 5th most abundant element in plants.
- It is the 1st or 2nd most commonly limiting nutrient.
- Inorganic phosphates (H2PO-, HPO42-, and PO43-) are available in soil, depending on soil pH.
Phosphorus Cycle
- Phosphorus does not enter the atmosphere.
- It mainly cycles through water, soil, and sediments.
- Phosphorus compounds primarily reside in rocks.
Phosphate Foraging: Root System Architecture
- Roots change angle, spreading lateral roots horizontally.
- Increased formation and elongation of lateral roots and root hairs occur.
- Aerenchyma (air spaces) allows metabolically inexpensive growth.
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