Starter: True or False
Ext. If it is false, what should the answer be?
Life on Earth: The Nitrogen Cycle
Nat 4 Unit 3
The Nitrogen Cycle
Learning Intention:
To learn about the nitrogen cycle
Success Criteria:
Why is nitrogen important?
The element nitrogen is the most common gas in the air around us.
It is needed by living organisms to make complex substances like DNA and proteins.
Living organisms cannot generally use the nitrogen straight from the air and so they rely on the uptake of nitrates from soil by plants.
Proteins…
We need nitrogen to make proteins. Proteins are essential for us to live.
The Nitrogen Cycle
Learning Intention:
To learn about the nitrogen cycle
Success Criteria:
Nitrogen Cycle
Nitrogen in the air
Nitrogen fixing bacteria in the soil or plant roots
Nitrates
Denitrifying bacteria
Uptake by plant roots
Plants make proteins
Animals eat plants
Dead material
Decomposers
Quick Draw
Nitrogen Cycle
Key Notes
Adding Nitrogen
How do farmers add nitrogen to the soil?
Fertiliser
Manure and special plants e.g. clover and beans
The Nitrogen Cycle is when nitrogen is recycled in nature so it can be used to make proteins for life. These are the processes that are involved in the cycle.
Nitrification
Nitrifying
Decomposers
Absorption
Denitrifying
Denitrification
Nitrogen fixation
Nitrogen fixing bacteria
The Nitrogen Cycle
To understand the nitrogen cycle I need to learn these key terms
Nitrification – how nitrates are made by nitrifying bacteria
Nitrifying bacteria – special bacteria that produce turn nitrogen into nitrates that is released into the soil
Decomposers – organisms e.g. bacteria and fungi that are responsible for breaking down the dead organic material so it can be used again.
Absorption – the taking in of minerals and water by osmosis and diffusion
Synthesis – to make something
Denitrifying bacteria – bacteria that converts nitrates in the soil back into nitrogen gas, which is then released into the atmosphere
Denitrification – conversion of nitrates to nitrogen gas by denitrifying bacteria
Nitrogen fixation – the conversion of nitrogen gas to nitrates by nitrogen fixing bacteria
Nitrogen fixing bacteria – bacteria found living in the soil or the root nodules of some plants and that convert nitrogen gas to nitrate
Key Words
The Nitrogen Cycle
Death and decomposition: organisms such as bacteria and fungi are responsible for breaking down the dead organic material. During this process protein is converted to ammonium.
The Nitrogen Cycle
Nitrification this involves nitrifying bacteria which change ammonium to nitrates. This process is vital because the nitrate produced can be absorbed by the plants roots.
The Nitrogen Cycle
Absorption and synthesis nitrates are soluble in water and are absorbed into plant root cells easily.
The Nitrogen Cycle
Nitrogen fixation – nitrogen fixing bacteria can convert nitrogen from the air to nitrates. nitrogen fixing bacteria live within the roots of certain plant cells. These plants include peas, beans and clover.
Summary
Living organisms need nitrogen to make p______. Plants can absorb n_______ from the soil. Ammonium is converted to nitrate in soil by the action of n_________ bacteria. Nitrogen – f____ bacteria, which live in soil and the roots of some plants, can use n______ from the air to make nitrates. In waterlogged soil, d___________ bacteria release nitrogen into the air.
roteins
itrates
itryfying
ixing
itrogen
ecomposing
Aim: To investigate the growth of cress seeds with and without nitrogen.
Investigating the importance of Nitrogen in plants
Task
TASK – in your group plan and carry out an experiment for the above aim – you need to include
List of equipment
Method
Safety
Result
Conclusion
Evaluation
You can use:
Cress seeds
Cotton wool
A few petri dishes
100cm liquid fertiliser
2 syringes
Checkpoint
On the white board
How do we get nitrogen?
Although the most abundant gas in our air we need to understand the nitrogen cycle to understand how we get our nitrogen.
Task: Use the National 4 text book to find out what these terms mean:
Revision task Questions