How Do DNA and RNA Polymerase Function and Differ in Error Rates?

[biophysics]

How do these enzymes "read" the template strand and "put in" the complementary nucleotide?

Also I've heard that DNA polymerase is less error prone than RNA polymerase. How is this accomplished?

 

[Ygggdrasil]

The enzymes let nucleotides diffuse into the active site and bind to the template strand. The enzymes are able to sense when the correct nucleotide has bound to the template by the geometry of the newly formed base pair. Once the enzyme has sensed that the correct nucleotide is bound, it can close its fingers domain, causing the active site to form and catalysis to occur.

DNA polymerase is less error prone in part because it has a 3'->5' endonuclease ability that allows it to remove mistakes (this occurs at the proofreading domain of the DNA polymerase).