What are macromolecules that contain nitrogen as well as carbon, hydrogen, and oxygen?

Proteins are macromolecules that are composed of amino acids, which contain carbon, hydrogen, oxygen, and nitrogen. The presence of nitrogen is a distinguishing characteristic of proteins, setting them apart from carbohydrates and lipids, which do not contain nitrogen in their basic structures.

Amino acids, the building blocks of proteins, feature an amino group that contains nitrogen, which is essential for forming the peptide bonds that link amino acids together to form proteins. Proteins play a critical role in biological processes, serving as enzymes, structural components, and signaling molecules.

While nucleic acids, such as DNA and RNA, also contain nitrogen, the context of the question emphasizes the broader category of macromolecules, where proteins are particularly well-recognized for their unique incorporation of nitrogen alongside carbon, hydrogen, and oxygen. Carbohydrates are composed mainly of carbon, hydrogen, and oxygen with no nitrogen present, and lipids primarily consist of carbon, hydrogen, and a small amount of oxygen and do not include nitrogen. Thus, proteins uniquely fulfill the criteria established in the question.