Organic molecules are best described as which of the following?

• A. Complex carbon and hydrogen containing molecules
• B. Not complex molecules
• C. Water molecules
• D. Inorganic minerals

Answer: (A)

Organic molecules are best described as complex carbon and hydrogen containing molecules. The defining feature of organic chemistry is carbon-based frameworks—carbon atoms can form long chains and rings, attach a variety of other atoms, and create diverse functional groups. This versatility allows organic molecules to be large and highly structured, enabling the complex chemistry of life such as carbohydrates, proteins, lipids, and nucleic acids. Water and inorganic minerals, by contrast, do not have carbon–hydrogen bonds and are not considered organic. Some carbon-containing compounds are inorganic, but in biology the hallmark description is that organic molecules are built around carbon and hydrogen cores.