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 is often found in various compounds, including hydrocarbons and alcohols. Methyl groups can influence the properties and reactivity of molecules, making them important in many chemical reactions. In biological systems, methyl groups play a crucial role in processes like DNA methylation, which can affect gene expression. Methylation is essential for regulating various cellular functions and is involved in development and disease. Understanding methyl groups helps scientists explore their significance in both chemistry and biology.