Question

What occurs when carbon is "fixed"?

A: It dissolves in water.
B: It is incorporated into the electron transport mechanism.
C: It is bonded to an organic compound.
D: It is oxidized.
E: It is phosphorylated.

Answer 1

When carbon is fixed, it is bonded to an organic compound, typically during photosynthesis where CO2 is transformed into sugars and other organic molecules necessary for life.

Step-by-step explanation:

When carbon is "fixed", it is bonded to an organic compound. During photosynthesis, carbon dioxide gas from the atmosphere or dissolved in water is converted to organic carbon. This carbon fixation involves taking inorganic carbon (CO2) and incorporating it into organic molecules like sugars. These sugars are then used to produce other types of organic molecules needed by organisms, such as lipids, proteins, and nucleic acids. For instance, the carbon that is used to make DNA in our cells was once part of CO2 that a photosynthetic organism fixed.