DNA Structure and Function In a strand of DNA, why does identifying the 3' side and the 5'side matter? Or the 3' --> 5' strand and the 5' --> 3' strand? Also, what is a single strand of DNA called, is it just a helix, or is the helix just the backbone?

A double strand is a helix, as the basepairs move with a horizontal angle with each step to the next basepair. Identifying the sides is important for DNA-replication and RNA synthesis as the way DNA is read is from 3' to 5' so that the complementary bases can be ''glued'' together from 5' to 3' in which the phosphate groups bind to the OH groups of the other molecule by a polymerase reaction. Disregard first answer.

There.