Last updated on August 30th, 2023 at 02:25 am
Class 8 Biology Nitrogen Fixation
Q: Which type of plants have a symbiotic relationship with Rhizobium bacteria?
A: Leguminous plants, such as beans and peas, have a symbiotic relationship with Rhizobium bacteria.
Q: How does nitrogen get fixed in the atmosphere?
A: Nitrogen gets fixed in the atmosphere through the action of lightning.
Q: Does the amount of nitrogen in the atmosphere change over time?
A: No, the amount of nitrogen in the atmosphere remains constant.
Q: Where does Rhizobium bacteria fix nitrogen from?
A: Rhizobium bacteria fix nitrogen from the atmosphere.
Q: How do microorganisms in the soil contribute to the survival of plants and animals?
A: Microorganisms in the soil convert atmospheric nitrogen into ammonium compounds, which are essential for the survival of plants and animals.
Q: What are some important biological molecules that contain nitrogen?
A: Nitrogen is an essential constituent of proteins, nucleic acids, chlorophyll and vitamins.
Q: Which organisms are able to fix nitrogen from the atmosphere?
A: Blue green algae and some bacteria are able to fix nitrogen from the atmosphere.
Q: What is the role of fungi in the nitrogen cycle?
A: Fungi are decomposers that degrade organic waste compounds into simple substances, which can be reused by plants in the nitrogen cycle.
Q: What percentage of nitrogen gas is present in our atmosphere?
A: Our atmosphere has 78% nitrogen gas.
Q: What are some of the essential biological molecules that contain nitrogen?
A: Nitrogen is a constituent of proteins, chlorophyll, nucleic acids and vitamins, which are essential biological molecules found in all living organisms.
Q: How do plants and animals obtain nitrogen from the atmosphere?
A: Plants and animals cannot take nitrogen directly from the atmosphere. Certain bacteria and blue green algae present in the soil fix atmospheric nitrogen and convert it into compounds of nitrogen that can be utilised by plants through their root system.
Q: What is the role of nitrogen in plant synthesis?
A: Nitrogen is an important component of plant proteins and other compounds that are synthesised by plants.
Q: How do animals obtain nitrogen?
A: Animals obtain nitrogen by feeding on plants, which provide them with the necessary proteins and other nitrogen compounds.
Q: What is the process by which atmospheric nitrogen is converted into usable compounds?
A: Certain bacteria and blue green algae present in the soil fix atmospheric nitrogen and convert it into compounds of nitrogen that can be utilised by plants.
Q: What is the nitrogen cycle?
A: The nitrogen cycle is the circulation of nitrogen between organisms and the atmosphere, which involves the conversion of nitrogen into various forms by microorganisms in the soil and the atmosphere.
Q: How do bacteria and fungi contribute to the nitrogen cycle?
A: Bacteria and fungi present in the soil convert nitrogenous wastes into nitrogenous compounds that can be used by plants again. Some bacteria convert some part of these compounds to nitrogen gas, which goes back into the atmosphere, thus keeping the percentage of nitrogen in the atmosphere constant.
Q: What is the role of microorganisms in the nitrogen cycle?
A: Microorganisms play an important role in the nitrogen cycle by converting nitrogen into various forms, such as nitrogenous compounds and nitrogen gas.
Q: How do some bacteria contribute to increasing soil fertility?
A: Some bacteria reside in the root nodules of leguminous plants and fix nitrogen from the air into the soil, which increases soil fertility.
Q: How is nitrogen fixed by lightning?
A: Nitrogen is fixed by lightning to a small extent, which involves the conversion of atmospheric nitrogen into usable compounds due to the high energy of lightning.
Q: What is the role of microorganisms in maintaining a clean environment?
A: Microorganisms in the soil decompose harmful and smelly substances, leading to a cleaner environment.
Q: How do microorganisms residing in the root nodules of leguminous plants contribute to soil fertility?
A: Microorganisms residing in the root nodules of leguminous plants can fix nitrogen from air into soil, which increases the soil fertility.
Q: How does the nitrogen cycle contribute to the availability of nitrogen in the soil?
A: The nitrogen cycle involves the conversion of nitrogen into various forms by microorganisms, which contributes to the availability of nitrogen in the soil for use by plants.
Q: What is nitrogen fixation and how is Rhizobium involved in it?
A: Nitrogen fixation is the conversion of atmospheric nitrogen into nitrogenous compounds. Rhizobium is a bacterium that lives in the root nodules of leguminous plants and is involved in the fixation of nitrogen in these plants.
