Carbohydrates, lipids, and proteins are categorized as what?

Carbohydrates, lipids, and proteins are categorized as compounds because they are made up of two or more different elements that are chemically combined in specific proportions. Each of these macromolecules is formed through the combination of elements—the basic building blocks of matter.

For example, carbohydrates are primarily composed of carbon, hydrogen, and oxygen, while lipids also consist of these elements but are structured differently. Proteins are formed from amino acids, which are compounds made up of carbon, hydrogen, nitrogen, oxygen, and sometimes sulfur. This unique combination of elements in specific arrangements gives each category of macromolecule its characteristic properties and functions in biological systems.

By contrast, elements are pure substances that cannot be broken down into simpler substances, and mixtures consist of two or more substances that are not chemically combined. Simple sugars, specifically, refer to the most basic form of carbohydrates and do not encompass the broader categories of lipids and proteins. Therefore, classifying carbohydrates, lipids, and proteins collectively as compounds accurately reflects their chemical nature and composition.