Bonding

In biological molecules, atoms and molecules are bonded together by strong and weak bonds.The strong bonds are

• ionic bonds- the electrostatic attraction between oppositely charged ions such as Na⁺ and Cl^-.
• covalent bonds- atoms share a pair of electrons and form a molecule. The attraction between the shared pair of electrons and the positive nuclei of the bonded atoms hold the atoms together.

Hydrogen bonds are weak electrostatic forces of attraction (bonds) between polar molecules containing hydrogen, oxygen and nitrogen.A polar molecule has an uneven distribution of charge with the nitrogen and oxygen atoms being slightly negative and the hydrogen atom being slightly positive.Weak intermolecular H-N and H-O bonds can form holding molecules together.