ALL ORGANISMS NEED A SOURCE OF CARBON
​- We can categorize organisms based on how they obtain CARBON from the environment. Organisms are categorized as either autotrophic or heterotrophicbased upon how they get their carbon. Carbon Source for Humans:
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​Humans get their carbon from consuming organic molecules.

• Sugars
• Proteins
• Lipids

Carbon Source for Prokaryotes:
Prokaryotes are more diverse in their metabolism. 

• AUTOTROPHS - organisms that can synthesize their own food from inorganic sources. For example, some prokaryotes can use the carbon in carbon dioxide (CO2) from the air
• HETEROTROPHS - organisms that cannot synthesize their own food. These organisms must consume organic molecules (sugars, proteins or lipids).

ALL ORGANISMS NEED A SOURCE OF ENERGY
​- We can categorize organisms based on how they obtain ENERGY from the environment. Organisms are categorized based upon how they get their energy. 
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