APES UNIT 1 - the nitrogen cycle

Created by

Gabby Amorim

Cards (55)

What is nitrogen needed for in cells?
Amino acids and nucleotides
Why are amino acids important for the body?
They are the building blocks of proteins that build our bodies
What percentage of our body is made up of water and protein?
60% water and 20% protein
What role do proteins play in the body?
They act as enzymes to carry out biochemical reactions
What are nucleotides the building blocks of?
DNA
What is the function of DNA?
It carries the code to build proteins, which build cells
What does DNA represent in terms of heredity?
It is the molecule of heredity, showing the passing down of genes
What is the biggest reservoir of nitrogen on Earth?
The atmosphere
Why is nitrogen gas (N₂) not usable by most organisms?
Because they lack the enzymes to fix it
What is the process of changing nitrogen gas into a solid called?
Fixing
Who is responsible for fixing nitrogen gas?
Bacteria
Why is nitrogen a limiting factor for plants?
Because it is scarce but vital for their growth
What are the steps of the nitrogen cycle?
Nitrogen Fixation
Ammonification
Nitrification
Assimilation
Denitrification
What is produced during nitrogen fixation?
Ammonia (NH₃)
What happens during ammonification?
Ammonia (NH₃) is converted to ammonium (NH₄⁺)
What is nitrification? 
A two-step process that converts ammonium (NH₄⁺) to nitrite (NO₂⁻) and then nitrate (NO₃⁻)
What form of nitrogen can plants take up?
Nitrate (NO₃⁻)
What do plants do with nitrates?
They make amino acids and nucleotides
What is denitrification? 
The conversion of nitrates back into nitrogen gas
What human activity contributes to soil erosion and degradation?
Agriculture
How does tilling affect nitrogen-fixing bacteria?
It eradicates nitrogen-fixing bacteria over time
Why do farmers use fertilizers?
To supply more nitrogen and phosphorus to crops
What is fertilizer run-off?
When rain causes fertilizer to wash off into local waters
What is eutrophication? 
A nutrient-rich body of water caused by excess nitrogen and phosphorus
What happens to algae during eutrophication?
They bloom quickly and then die, consuming oxygen in the water
What is a consequence of algae dying in water?
It can lead to hypoxia, where aquatic life dies from lack of oxygen
What is one effect of burning fossil fuels on the nitrogen cycle?
It releases nitrogen into the atmosphere
What are two results of nitrogen release from burning fossil fuels?
Acid rain and photochemical smog
What are the products of each step in the nitrogen cycle?
| Step | Product |
|-----------------|-----------------|
| Nitrogen Fixation | Ammonia |
| Ammonification | Ammonium |
| Nitrification | Nitrite → Nitrate |
| Denitrification | N₂ |
What is nitrogen needed for in cells?
Amino acids and nucleotides
Why are amino acids important for the body?
They are the building blocks of proteins that build our bodies
What percentage of our body is made up of protein?
20%
What role do nucleotides play in biochemical reactions?
They act as enzymes and are building blocks of DNA
What is the significance of DNA in living organisms?
DNA carries the code to build proteins and is the molecule of heredity
What is the largest reservoir of nitrogen on Earth?
The atmosphere
What does it mean to "fix" nitrogen in biology?
It refers to changing nitrogen from a gas into a solid form
Why can't humans fix nitrogen gas?
Humans lack the necessary enzymes to do so
Which organisms are responsible for nitrogen fixation?
Bacteria
How does abiotic lightning affect nitrogen fixation?
It acts as a limiting factor for plants
What are the steps of the nitrogen cycle?
Nitrogen Fixation
Ammonification
Nitrification
Assimilation
Denitrification