Carbon and Nitrogen Cycle
*Watch the Amoeba Sisters Video: Amoeba Sisters Video: Carbon and Nitrogen Cycle
*Carbon Cycle
1. Carbon is a very important element in your body. What are some of the reasons that
organisms need carbon?
Building cells/ Food (glucose)/ Growth/ Reproduction
2. The carbon cycle is a cycle among the carbon reservoirs. What is a carbon reservoir?
Carbon reservoirs store carbon...examples are the atmosphere, biosphere, ocean
and rocks.
3. Differentiate between a carbon sink and carbon source...relate to photosynthesis and
respiration.
● Carbon sinks remove more CO2 than is released...occurs during the
daylight and summer. CO2 removed by photosynthesis (chloroplast) is
greater than the CO2 released from respiration (mitochondria).
●
Carbon sources release more CO2 than is removed...occurs during the
nighttime and winter. CO2 released from respiration (mitochondria) is
greater than CO2 removed by photosynthesis (chloroplast).
*Nitrogen Cycle
1. Nitrogen is a very important element in biology. What are some of the reasons that
organisms need nitrogen?
● Makes up proteins (proteins are made of amino acids=NH2)
● Makes up DNA (DNA is made up of nitrogenous bases, sugar and a
phosphate group)
2. Nitrogen gas is more abundant in our atmosphere than oxygen! However, nitrogen
needs to be converted into different forms to be used by many organisms. Bacteria are
highly involved in this! Describe the role of A) bacteria fixing nitrogen as they live
symbiotically with some plant species, B) nitrifying bacteria and C) denitrifying bacteria in
the nitrogen cycle.
● N-fixing bacteria change atmospheric nitrogen gas into a solid that plants
can use.
● Nitrifying bacteria convert soil ammonia into nitrates that can be used by
plants.
● Denitrifying bacteria convert soil nitrates into atmospheric nitrogen gas.
3.
How do we get the nitrogen we need for our bodies?
We eat plants or animals that eat plants to get nitrogen in a form that our bodies
can use to make proteins and DNA.