The chemical group "-CH3" is known as a methyl group. It consists of one carbon atom bonded to three hydrogen atoms. Methyl groups are commonly found in organic compounds and play a significant role in the structure and function of various molecules, including amino acids and lipids. Methyl groups can influence the properties of compounds, such as their solubility and reactivity. They are also important in biological processes, including gene expression and metabolism. The presence of a methyl group can affect how molecules interact with each other, making it a key feature in organic chemistry.