Hydrogen bond

Definition

A hydrogen bond is a weak interaction between a hydrogen atom bound to a highly electronegative atom (such as oxygen or nitrogen) and another electronegative atom. This type of bond is crucial in many biological molecules, including water and DNA.

5 Must Know Facts For Your Next Test

1. Hydrogen bonds are essential for the unique properties of water, such as its high specific heat and surface tension.
2. In DNA, hydrogen bonds hold the base pairs together, stabilizing the double helix structure.
3. Hydrogen bonds are weaker than covalent and ionic bonds but stronger than van der Waals forces.
4. They play a critical role in the secondary and tertiary structures of proteins by helping to stabilize alpha-helices and beta-pleated sheets.
5. Hydrogen bonding occurs not only in water but also in ammonia, alcohols, and various other organic compounds.

Review Questions

• What role do hydrogen bonds play in the structure of DNA?
• How do hydrogen bonds contribute to the properties of water?
• Compare the strength of hydrogen bonds to that of covalent and ionic bonds.

Related terms

Covalent Bond: A strong chemical bond formed by the sharing of electron pairs between atoms

Ionic Bond: A chemical bond formed through the electrostatic attraction between oppositely charged ions

Van der Waals Forces: Weak attractions or interactions between molecules due to temporary dipoles