A methyl group is a simple chemical structure consisting of one carbon atom bonded to three hydrogen atoms, represented as CH₃. It is a common functional group in organic chemistry and plays a crucial role in the structure and behavior of many organic compounds. Methyl groups can influence the properties of molecules, such as their solubility and reactivity. Methyl groups are often found in various biological molecules, including DNA and proteins. They can affect gene expression through a process called methylation, where methyl groups attach to DNA and regulate how genes are turned on or off. This makes them important in genetics and biochemistry.