Molecules can either be Organic or inorganic (Most molecules within an
organism are organic). The pie chart bellow illustrates what makes up your cells and in what quantities. Nearly 70% of your cell is made up of water!
Oxygen (O2)
Almost all cells require oxygen to survive. Without oxygen we can not obtain energy from our food (cellular respiration). Organisms which live on land or breath the air can easily obtain oxygen, as the atmosphere is 21% oxygen. Organisms which live underwater, have a harder time obtaining oxygen, because it isn’t very soluble in water. Organisms which live in water often have very efficient ways of obtaining oxygen. I.e. gills
Carbon dioxide (CO2)
Carbon is the main component in all organic molecules. Although it contains carbon, it is considered an Inorganic molecule because it is not complex enough and does not contain hydrogen. Carbon dioxide is absorbed by plants, some bacteria and protists from the atmosphere. Plants use CO2 to create sugars through photosynthesis. CO2 is returned to the atmosphere via cellular respiration and the decay of organic materials.
Click here to learn more about the carbon cycle
Nitrogen (N2)
Nitrogen is an extremely important molecule as it is a key component in proteins.
The atmosphere is around 78% nitrogen. Bacteria capture this nitrogen and convert it into usable compounds. This is called nitrogen fixation. This is then used by plants.
To learn more about the nitrogen cycle click here.
Animals use Calcium to strengthen their bones and plants use silicon in their Cell Walls.
Are all extremely important minerals used by cells. Minerals can be absorbed by plant roots from the soil. Humans require more than 20 different minerals, however some in small amounts.
The main difference between organic and inorganic molecules is that Organic molecules have a carbon backbone, oxygen, hydrogen and sometimes nitrogen and phosphate molecules . They are also much larger and more complex than inorganic molecules
