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 peptide bond (amide bond) is a covalent chemical bond formed between two amino acid molecules. peptide bond can be broken by hydrolysis (the adding of water). In the presence of water they will break down and release 8â16 kilojoule / mol (2â4 kcal / mol) of free energy. This process is extremely slow. In living organisms, the process is catalyzed by enzymes.