Methyl is a chemical group consisting of one carbon atom bonded to three hydrogen atoms, represented as CH₃. It is a fundamental building block in organic chemistry and plays a crucial role in the structure of many compounds, including hydrocarbons and alcohols. Methyl groups can influence the properties and reactivity of molecules, making them important in various chemical reactions. In biological systems, methyl groups are involved in processes such as DNA methylation, which can affect gene expression. Methylation is essential for regulating cellular functions and development. Additionally, methyl groups are found in many natural products and pharmaceuticals, contributing to their biological activity and effectiveness.