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.
A water molecule can accept two hydrogen atoms and donate two which means it can form up to four hydrogen bonds. Compared to the covalent bonds within the water molecule itself hydrogen bonding is a relatively weak attraction but it is responsible for a number of waterâs properties.