A biological molecule is a large, complex molecule that is essential for life. These molecules include proteins, nucleic acids, carbohydrates, and lipids. They play critical roles in various biological processes, such as energy storage, genetic information transfer, and cellular structure. Proteins, for example, are made up of amino acids and are involved in nearly every function within living organisms. Nucleic acids, like DNA and RNA, carry genetic information. Carbohydrates provide energy and structural support, while lipids are important for cell membranes and energy storage. Together, these molecules are fundamental to the structure and function of all living cells.