Multiple choice Which enzyme unwinds DNA and how does it do this? DNA Polymerase III by breaking hydrogen bonds Helicase by breaking hydrogen bonds DNA Polymerase III by breaking covalent bonds Helicase by breaking covalent bonds Reveal answer Fill a bubble to check yourself B Correct answer Explanation Helicase is the enzyme that unwinds the DNA double helix by breaking the hydrogen bonds between the complementary nitrogenous bases.