Which sequence correctly matches each bacterium to its primary role in the nitrogen cycle: nitrogen fixation, nitrification and denitrification?
Azotobacter - nitrogen fixation, Nitrobacter - nitrification, Pseudomonas - denitrification
Azotobacter is a free-living soil bacterium that converts atmospheric nitrogen gas (N2) into ammonia, which plants can use. So its role is nitrogen fixation.
Nitrification is the conversion of ammonia into nitrites and then nitrates. Nitrosomonas changes ammonia to nitrite, and Nitrobacter oxidises nitrite to nitrate, so Nitrobacter is the nitrifying bacterium.
Denitrification returns nitrogen to the air: nitrates in the soil are reduced to nitrogen gas. Pseudomonas is a well-known denitrifying bacterium.
So the correct matching is Azotobacter with nitrogen fixation, Nitrobacter with nitrification and Pseudomonas with denitrification. Every other sequence gives at least two of these bacteria the wrong role.
Hence, Azotobacter - nitrogen fixation, Nitrobacter - nitrification, Pseudomonas - denitrification.
Similar Questions
How do plants help maintain the carbon cycle by absorbing carbon dioxide from the atmosphere?
Which statement accurately compares the carbon content of the oceans to that of the atmosphere?
A city plans to build a landfill which is near a river and farmland to manage growing waste. Which strategy best protects the ecosystem while supporting urban development?
Which of the following pairs of articles does NOT represent nonbiodegradable substances?
Which sequence describes effects of deforestation (biosphere) leading to consequent changes in the atmosphere, hydrosphere, and geosphere?
Soil fertility would decline if fungi were removed from an ecosystem as:
In an ecosystem, organisms that can prepare their own food using sunlight are known as _______________.
In a grassland food web, which of the following would most likely happen if the population of primary consumers such as rabbits dramatically decreased?
How does the atmosphere help maintain suitable temperatures for life on Earth?
Which of the following methods is NOT applied for disposal of nonbiodegradable substances?
Important Questions from Ecology & Environment
Which of the following isnotan adaptation for Xerophytes?
One horned Rhinoceros is a conserved species at:
Who amongst the following forms the first trophic level in an ecosystem?
- Which of the following is a non-biodegradable item?
Primary consumers are
