Each molecule contains hundreds of millions of atoms in a specific and unique sequence. They are shaped like a ladder twisted into a spiral. Ex: telephone cord

The rugs are called nucleotides, they are in the ladder.

The rail of the ladder consists of alternating molecules of sugar and phosphate. The ladder has 4 nucleotides, each of which is half of a complete entry base pair. Each one goes with its mate on the opposite rail like two pieces of jigsaw puzzle.

How are the molecules and what parts are there?