Question

Which forces allow for temporary strand separation during DNA replication and transcription?

Options

• Phosphodiester bonds

• Disulfide bridges

• Covalent bonds in the sugar ring

• Hydrogen bonds between complementary bases

Answer 1

Hydrogen bonds between complementary base pairs are non-covalent (weak) interactions that can be broken and reformed. This property allows the DNA strands to separate temporarily during replication (to allow semiconservative copying) and transcription (to allow RNA polymerase access). The weakness of hydrogen bonds, combined with the strength of phosphodiester bonds maintaining the backbone, creates a structure that is both stable and flexible.