Among the four macromolecules—carbohydrates, lipids, proteins, and nucleic acids—proteins and nucleic acids are the ones that contain nitrogen.
Proteins are primarily made up of amino acids, and each amino acid contains an amine group (-NH2) that includes nitrogen. This nitrogen is essential for the structure and function of proteins, facilitating the formation of peptide bonds that link amino acids together.
Nucleic acids, such as DNA and RNA, also contain nitrogen in their nucleotide components. The nitrogenous bases (adenine, thymine, cytosine, guanine, and uracil) found in these molecules incorporate nitrogen atoms, which plays a crucial role in genetic coding and the overall structure of nucleic acids.
In contrast, carbohydrates and lipids do not contain significant amounts of nitrogen. Carbohydrates are mainly composed of carbon, hydrogen, and oxygen, while lipids primarily consist of carbon and hydrogen with very little to no nitrogen.