06 the nitrogen cycle Flashcards
what is nitrogen
Nitrogen is a element that
is essential to life.
– It makes up almost 80% of the Earth’s
atmosphere.
– It is also found in DNA, RNA, and chlorophyll
what is the nitrogen cycle?
the series of processes by which
nitrogen and its compounds are exchanged
between the environment and living organisms.
can humans absorb nitrogen gas as it is?
no, it must go through a process before it can absorbed.
NOTE
make sure you see the nitrogen gas diagram
at the beginning of the nitrogen cycle when the nitrogen is in the atmosphere, it is then taken in by either _________ and/or _______
this is called what?
bacteria in the roots of
legumes,
- and bacteria in the soil.
Nitrogen fixing
what are legumes
Legumes are a type of plant that contains bacteria that contribute to the nitrogen cycle. For example, peas.
after the nitrogen gas is taken in by the bacteria, what does the bacteria convert it into?
ammonia
N2 yields NH3
after ammonia is created In the nitrogen cycle, what is it turned into? what is this process called? Why does this happen?
ammonium
ammonification
because ammonia is an unstable molecule
—organisms can absorb the ammonium but it is not very common
after ammonification (in the nitrogen cycle), what process occurs, and what happens in this process
Nitrification The ammonium is taken in by bacteria is the soil. It is converted by bacteria into nitrites. Nitrites are NO2- ---------------------------- The nitrites are converted once again by bacteria into nitrates. Nitrates are NO3- Nitrites are NO2-
after the process of nitrification in the nitrogen cycle, what process takes place and what happens in this process?
The nitrates (NO3 -) are absorbed into the plant through the process of assimilation. Animals then eat the plants and gain their nitrogen. This is how organisms get the nitrogen that is essential to life.
after the process of assimilation takes place, humans and animals can obtain this nitrate from some foods (i.e. nuts). What process comes after assimilation? what happens at this stage?
denitrification This is when bacteria in the soil convert the nitrates (NO3 -) into nitrogen gas (N2). This then completes the nitrogen cycle.
besides the nitrogen cycle, what is one way for nitrogen to get into the soil? explain this process?
Decomposition occurs when organisms are decomposed by bacteria. Bacteria convert the organic matter into ammonium.
what are the names of the steps involved in the nitrogen cycle
ammonification.
nitrification.
assimilation.
denitrification.
what percent of the earth’s atmosphere is composed of nitrogen?
78%
What are some examples of
plants that perform the process of nitrogen
fixing?
bacteria,
