Explain nitrogen cycle in simple words ?
and explain oxygen cycle ?
Answers
1.The atmospheric nitrogen is fixed into nitrogen compounds like nitrates by Rhizobium bacteria, blue green algae and lightning.
2. The plants absorb nitrate compounds from the soil and water and convert them into plant proteins.
3.The plants are eaten up by animals and thus plant proteins are used for making animal proteins.
4.When the plants and animals die the putrefying bacteria and fungi present in the soil decompose the protein of dead plants and animals into ammonia.This process is called a ammonification.
5.Ammonia thus formed is converted first into nitrites and then into nitrates by the action of Nitrosomonas and Nitrobacter bacteria respectively .The process is called Nitrification. These nitrates are again absorbed by the plants and the cycle is repeated.
6.The soil contains denitrifying bacteria called pseudomonas which converts nitrate form of nitrogen into free nitrogen which goes back into the atmosphere. The process is called denitrification.
steps involved in oxygen cycle:
1. photosynthesis :–
During the day, plants take energy from the sun, carbon di oxide from the air, and water from the soil to make their food. Their food is simple – glucose. This process is called photosynthesis. Oxygen is released into the air as a by-product of photosynthesis.
During the night, plants take in oxygen and release carbon di oxide, to maintain their metabolism. Which is why it is not a good idea to sleep under trees at night.
2. Respiration :–
The oxygen that is released by plants is used by humans, animals, and other organisms for respiration, i.e. breathing. We use oxygen to break down simple sugars and generate energy to sustain ourselves. During respiration, organisms take in oxygen and release carbon di oxide into the air.
3. Repeat :–
This carbon dioxide is again, taken up by plants, for photosynthesis.
Thus, we see that our life force is generated chiefly by plants. Which is why it is super important to preserve plant life on earth.
Answer:
Oxygen Cycle
Oxygen is the second most abundant element in the atmosphere and is present to the extent of about 21 per cent and is essential for all life processes. Atmosphere and oceans are the main pool for oxygen. The oxygen dissolved in water (oceans, etc.) is responsible for sustaining aquatic plants and animals. It is also a constituent of oxide and carbonate ores. There is a continuous exchange of oxygen between the atmosphere and water surfaces of all water bodies. The total amount of oxygen in the biosphere is constant. The oxygen cycle is based on the exchange of oxygen among the segments of the environment, viz., atmosphere, hydrosphere, lithosphere and biosphere. It plays a key role in atmospheric chemistry and life process. The different steps involved in oxygen cycle are:
During respiration, organisms including animals and human beings consume oxygen from the air and give carbon dioxide into the atmosphere.
The green plants utilize carbon dioxide for photosynthesis, in which carbon dioxide reacts with water in presence of solar energy and a catalyst (chlorophyll) to produce carbohydrates and the formed oxygen is released into the atmosphere.
Oxygen is needed by bacteria and fungi during decomposition of organic matter. The products of decomposition (CO2 and H2O) are released into the atmosphere. The released CO2 and H2O are utilised during photosynthesis by green plants.