Final answer:
A molecule is composed of two or more atoms bonded together, and can range from simple combinations like oxygen gas to complex macromolecules like DNA, essential for the functioning of living organisms. The mass number of an atom is unrelated to a molecule's structure but defines atom's characteristics within a molecule. Molecule structural formulas use subscripts to denote numbers of atoms.
Step-by-step explanation:
A molecule is an electrically neutral group of two or more atoms held together by chemical bonds. In biology and chemistry, molecules can range from simple combinations of two atoms, like oxygen gas (O2), to complex organic structures like deoxyribonucleic acid (DNA), which is a macromolecule. Macromolecules are typically composed of repeating units called monomers, forming polymers that have a wide variety of functions in living organisms.
For example, DNA is a macromolecule that contains the instructions for the structure and functioning of all living organisms, thus playing a critical role in the transmission of genetic information. Molecules are fundamental to the study of both organic and inorganic substances and are crucial in understanding the composition and properties of matter. In addition to their composition, the ways in which atoms bond in a molecule, such as through nonpolar covalent bonds or polar covalent bonds, determine the molecule's properties.
The mass number of an atom, which is the sum of its protons and neutrons, does not directly affect the molecule's structure but is important in understanding the atom's characteristics within the molecule. Structural formulas commonly use subscripts to indicate the number of atoms of a kind in the molecule, such as H2O, which represents a water molecule.