Hypernyms (to doodle is one way to...): draw (represent by making a drawing of, as with a pencil, chalk, etc. on a surface). Doodle entails doing...: delineate; describe; draw; line; trace (make a mark or lines on a surface).
DNA polymerases can only extend a DNA strand in a 5â² to 3â² direction, different mechanisms are used to copy the antiparallel strands of the double helix. In this way, the base on the old strand dictates which base appears on the new strand.
The enzyme is 3' to 5' because it scans in the opposite direction of DNA replication, which we learned must always be 5' to 3'. The mechanism of the proof-reading system offers an explanation as to why DNA replication must occur in this direction.