Carbon and nitrogen cycles Flashcards
What is an ecosystem?
A community of organisms living in an area as well as the nonliving, abiotic, conditions.
What is a biotic component of an ecosystem?
A living organism
Materials that organisms need to survive, such and carbon and nitrogen, are recycled through which components of ecosystems?
Biotic and abiotic
What is an abiotic component of an ecosystem?
Nonliving components such as air, rocks and soil
What is meant by ‘recycled’ in terms of the carbon cycle?
There is only a fixed amount of carbon in the world, therefore it is in a continuous cycle
The carbon cycle is powered by what?
Photosynthesis
Green plants use the carbon from CO2 to make………
Carbohydrates
Lipids
Proteins
Eating the green plants passes the carbon compounds along to………..
Animals
What is carried out by living plants and animals that releases CO2 back into the air?
Respiration
When animals and plants die, they decay, and are broken down by micro organisms and eventually turn into………
Fossil fuels
What are the micro organisms that breakdown decomposing animals and plants called?
Decomposers
Give two examples of micro organisms that are decomposers?
Bacteria
Fungi
What do the microorganisms, known as decomposers, release?
Enzymes, which catalyse the breakdown of dead material into smaller molecules and CO2 back into the air
When some useful plant and animal products, such as wood and fossil fuels, are burnt what is released into the air?
CO2
What percentage of our atmosphere is nitrogen gas?
About 78%
What is Nitrogen needed for?
Making proteins for growth
Where do plants get their nitrogen from?
The soil
What does the nitrogen in the air have to be turned into four plants can use it?
Nitrogen compounds such as nitrates
Where do animals get their proteins from?
Eating plants or eating each other
What is nitrogen fixation?
It is the process of turning N2 from the air into nitrogen compounds in the soil which plants can use
What are the two main ways nitrogen fixation can happen?
Lightning - The energy in a bolt of lightning makes Nitrogen react with oxygen in the air to give nitrates.
Nitrogen fixing bacteria - found in soil and the roots of some plants
Name the four different types of bacteria involved in the nitrogen cycle
Decomposers
Nitrifying bacteria
Nitrogen fixing bacteria
Denitrifying bacteria
What do decomposers do?
Breakdown proteins and urea and turn them into ammonia. This forms ammonium ions in the soil.
What do nitrifying bacteria do?
Turn ammonium ions in decaying matter into nitrates (nitrification)
What do nitrogen-fixing bacteria do?
Turn atmospheric N2 into nitrogen compounds that plants can use
What does denitrifying bacteria do?
Turn nitrates back into N2 gas. This is of no benefit to living organisms.
