The modern working definition of a gene is a portion (or sequence) of DNA that codes for a known cellular function or process (e.g. the function make melanin molecules). A single 'gene' is most similar to a single 'word' in the English language.
Polar covalent bonds hold the actual hydrogen and oxygen atoms within the molecule of water but if you meant what holds water together as a liquid then that is called hydrogenâ¦ bonding between molecules, a type of dipole interaction.
Structural Biochemistry/Chemical Bonding/Hydrogen bonds - Hydrogen bonding in water. 1  The simplest example of a hydrogen bond can be found in water molecules. A water molecule consists of one oxygen atom attached to two hydrogen atoms. 2  Although water has a low molecular mass, it has an unusually high boiling point.