Question

how are DNA and RNA polymerases similar?

Answer 1

one of the RNA polymerases require primers, and all of the DNA polymerases do.

DNA polymerases are much more accurate, making an error only once in 10 to the 7th times, whereas RNA polymerases are more prone to errors, making them 1 in 10 to the 4th times.

They are both similar in terms of shape. DNA polymerase looks like a hand, RNA polymerase resembles a crab claw. Both use ions like Mg2+ in the active site, but DNA has 2 ions whereas RNA only has 1 (the 2nd one is brought with the nucleotide).

DNA polymerases are processive...they move across a DNA strand whereas RNA polymerases thread DNA into themselves.

Both have accuracy mechanisms. The DNA polymerase has a subunit that is an exonuclease that cuts wrong nucleotides that are inserted. However, the RNA polymerase accuracy checking occurs by chance through a reverse process of the addition reaction...wrong nucleotides stay in the active site longer and have a greater chance of being reversed.