Ciclo do Nitrogênio - Ciclos Biogeoquímicos - Ecologia - Biologia com o Tubarão

Summary

In this engaging and lively biology lesson, the instructor delves deep into the nitrogen cycle, highlighting its importance in ecology. They explain the atmospheric nitrogen's role in forming proteins through its interaction with legumes and bacteria like Rhizobium. The process of ammonification, nitrosation, nitrification, and denitrification is also explored, detailing how bacteria transform nitrogen compounds into usable forms for plants. The teacher emphasizes the vital role of bacteria in sustaining the nitrogen cycle, which ultimately provides the nitrogen essential for plant growth and, consequently, for human consumption. The instructor wraps up by encouraging students to subscribe, share, and support the educational platform.

Takeaways

• 😀 Nitrogen makes up 75-78% of the Earth's atmosphere, but it is not directly usable by most living organisms.
• 😀 Nitrogen is essential for forming proteins, as it is a key component of amino acids.
• 😀 Leguminous plants, like beans, have root nodules containing *Rhizobium* bacteria, which can fix atmospheric nitrogen into a usable form for the plant.
• 😀 Ammonification is the process in which organic matter is broken down into ammonia (NH₃) by decomposers like bacteria and fungi.
• 😀 Ammonia (NH₃) is toxic, so it must be converted into less harmful substances for living organisms.
• 😀 Nitrosation, or nitrification, involves the conversion of ammonia into nitrites (NO₂⁻) by bacteria like *Nitrosomonas* and *Nitrosococcus*.
• 😀 Nitrification continues as nitrites are further converted into nitrates (NO₃⁻) by bacteria like *Nitrobacter*, which plants can easily absorb.
• 😀 Nitrate assimilation occurs when plants absorb nitrates from the soil to produce amino acids and proteins.
• 😀 Denitrification is the process where bacteria like *Pseudomonas* convert nitrates back into atmospheric nitrogen (N₂), completing the nitrogen cycle.
• 😀 Bacteria involved in the nitrogen cycle are chemosynthetic, deriving energy from chemical reactions, such as oxidizing ammonia or nitrite, to fuel their metabolic processes.

Q & A

What is the main topic of this biology class?

The main topic is ecology, specifically focusing on the nitrogen cycle.

Why is nitrogen important for living beings?

Nitrogen is crucial because it is a key component in the formation of proteins, which are necessary for life. It is part of amino acids that make up proteins.

What is the nitrogen cycle?

The nitrogen cycle is a series of processes through which nitrogen is converted into different forms in the environment, making it accessible to plants and animals.

What role do legumes play in the nitrogen cycle?

Legumes, through a mutualistic relationship with bacteria of the genus *Rhizobium*, help fix atmospheric nitrogen into a form that plants can use by forming root nodules.

What is the process of ammonification in the nitrogen cycle?

Ammonification is the process by which bacteria decompose organic matter and convert nitrogen into ammonia (NH3), which is released into the soil.

What happens during the process of nitrification?

Nitrification is the process where ammonia is first oxidized into nitrite (NO2-) by bacteria such as *Nitrosomonas*, and then the nitrite is further oxidized into nitrate (NO3-) by bacteria like *Nitrobacter*.

How do plants use nitrogen in the form of nitrate?

Plants absorb nitrate from the soil and use it to form amino acids, which are then used to produce proteins essential for plant growth and development.

What is denitrification in the nitrogen cycle?

Denitrification is the process by which certain bacteria, such as *Pseudomonas*, convert nitrate back into atmospheric nitrogen (N2), completing the nitrogen cycle.

What is the significance of chemosynthetic bacteria in the nitrogen cycle?

Chemosynthetic bacteria, like *Nitrosomonas* and *Nitrobacter*, use chemical energy from the oxidation of ammonia and nitrite to produce food for themselves, indirectly helping plants by converting nitrogen into forms they can use.

How does decomposition contribute to the nitrogen cycle?

Decomposition breaks down organic matter into inorganic substances, including ammonia, which can then be used by plants or converted into nitrites and nitrates by bacteria, further enriching the soil.