Which of the following is a key function of proteins in cells?

The synthesis of hormones is a key function of proteins in cells because hormones are biochemical messengers that regulate various physiological processes in the body. Proteins, which are made up of amino acids, are essential in the production of hormones such as insulin, growth hormone, and adrenaline. These proteins are synthesized through transcription and translation processes based on the genetic instructions encoded in DNA.

While energy storage, cellular respiration, and managing water balance are important biological functions, they are not primarily performed by proteins. Energy storage is typically associated with carbohydrates and fats, cellular respiration involves various metabolic pathways that include enzymes but extend beyond just proteins, and the regulation of water balance often involves other molecules, such as aquaporins, which are a specific class of proteins but highlight that multiple components are involved in these processes. The central role of proteins in hormone synthesis underscores their versatility and importance in cellular functions.