Which macromolecule is primarily responsible for the structure and function of hormones?

Proteins are primarily responsible for the structure and function of hormones due to their versatile roles in the body. Hormones, which are chemical messengers, often consist of protein molecules or are derived from amino acids, making them integral to many physiological processes. These protein hormones can bind to specific receptors on target cells, initiating responses that regulate metabolism, growth, immune function, and mood, among other functions.

The structure of proteins allows them to have a wide variety of shapes and sizes, which is crucial for their interaction with specific receptors and the initiation of cellular responses. This specificity is vital for hormones to exert their effects accurately and effectively.

In contrast, while carbohydrates can play roles in cellular recognition and signaling, they do not typically function as hormones. Nucleic acids, primarily involved in genetic information storage and transmission, do not serve as hormones either. Lipids, particularly steroids, can also function as hormones, but many hormones, including peptide hormones like insulin and glucagon, are proteins. Thus, in the broader context of hormone functionality and structure, proteins are the predominant macromolecule responsible.