Test: Nitrogen Cycle and its Relevance to the Environment - 1 - JAMB MCQ

Photosynthesis is the process by which plants convert carbon dioxide and water into glucose and oxygen. It does not directly involve the nitrogen cycle.

The atmosphere is the primary source of nitrogen, which is mostly in the form of nitrogen gas (N₂).

Nitrogen fixation is the conversion of atmospheric nitrogen gas (N₂) into ammonia (NH₃) by certain nitrogen-fixing bacteria or through industrial processes.

Nitrifying bacteria are responsible for the conversion of ammonia (NH₃) into nitrite (NO₂^-) and then into nitrate (NO₃^-) during nitrification.

Denitrification is the process by which nitrate (NO₃^-) is converted back into nitrogen gas (N₂) by denitrifying bacteria, thus returning nitrogen to the atmosphere.

Deforestation disrupts the nitrogen cycle by reducing the number of plants and trees that absorb nitrogen from the soil, leading to increased nitrogen runoff and potential pollution.

Excessive nitrogen runoff from agriculture can lead to nutrient enrichment in water bodies, causing algal blooms. Algal blooms consume oxygen during decomposition, leading to oxygen depletion and negatively impacting aquatic organisms.

Leguminous plants have a symbiotic relationship with nitrogen-fixing bacteria in their root nodules, allowing them to convert atmospheric nitrogen into forms that can be used by plants.

The burning of fossil fuels releases nitrogen oxides (NOx) into the atmosphere, which can eventually lead to increased nitrogen gas (N₂) in the atmosphere, disrupting the balance of the nitrogen cycle.

Biological nitrogen fixation occurs when certain bacteria, such as Rhizobium, form symbiotic relationships with leguminous plants and convert atmospheric nitrogen into a usable form, such as ammonia.