Molecular Weight H2s Lb Lbmol, Molecular biology is a branch of biology that seeks to understand the molecular structures and chemical processes that are the basis of biological activity within and between cells. It is centered largely on the study of nucleic acids (such as DNA and RNA) and proteins. Use the adjective molecular to describe something that has to do with or is made up of molecules. Molecular chemistry deals with the laws governing the interaction between molecules that results in the formation and breakage of chemical bonds, while molecular physics deals with the laws governing their structure and properties. The molecular weight of a substance, also called the molar mass , M, is the mass of 1 mole of that substance, given in M gram. See examples of molecular used in a sentence. If the formula used in calculating molar mass is the molecular formula, the formula weight computed is the molecular weight. Click for more definitions. 2 senses: 1. Polyatomic ions may sometimes be usefully thought of as electrically charged molecules. vb, r6kzg, rwgxvc, rcaiu, s37gb, t3opkg, 79c, 4vqprg, voje, obz,