What is the importance of hydrogen bonds?

Question

importance of it in a biological system

Answer 1

Without hydrogen bonds, there would be no complementary relationship of DNA base pairs, and no way to "read" the code of DNA into mRNA and thence to the formation of proteins.

Without hydrogen bonds, protein secondary structures like alpha helices and beta sheets would not form, so proteins and enzymes would not function properly.

Without hydrogen bonds, there would be no correct binding of substrates to enzyme active sites, or poor discrimination among potential substrates.

Without hydrogen bonds, the polar end of phospholipids wouldn't interact so strongly with water, so there would be no proper formation of lipid bilayer membranes or liposomes, and compartmentalization in cells could not occur.

Without hydrogen bonds, water would not be a liquid at ambient temperature and pressure.  So, you know, no solvent to do any chemistry in.  Makes biology tough.

In short, the properties and function of all the most critical biological molecules -- amino acids, nucleic acids, and lipids -- as well as the solvent in which all biological chemistry occurs -- depends on inter- and intramolecular hydrogen bonding.

Answer 2

It is the basis of molecular recognition, including the recognition of complementary pairs in DNA replication, and substrate recognition in enzymatic catalysis.