What is the difference between DNA and RNA polymerase, and how do they function in transcription?

DNA and RNA polymerase differ in their structure and function during transcription.

DNA polymerase is responsible for replicating DNA during cell division. It adds nucleotides to the growing DNA strand in the 5' to 3' direction. It requires a template strand and a primer to initiate replication.

RNA polymerase, on the other hand, is responsible for transcribing DNA into RNA. It adds nucleotides to the growing RNA strand in the 5' to 3' direction. It does not require a primer, but it does require a promoter region to initiate transcription.

During transcription, RNA polymerase binds to the promoter region of the DNA template strand and begins to unwind the double helix. It then reads the template strand and adds complementary RNA nucleotides to the growing RNA strand. The RNA polymerase moves along the DNA template strand, unwinding the double helix and adding nucleotides until it reaches the termination sequence.

DNA polymerase and RNA polymerase also differ in their proofreading abilities. DNA polymerase has a proofreading function to correct errors in replication, while RNA polymerase does not. This is because RNA is a disposable molecule and any errors can be corrected during translation.

In summary, DNA and RNA polymerase have different structures and functions during transcription. DNA polymerase replicates DNA during cell division, while RNA polymerase transcribes DNA into RNA. RNA polymerase requires a promoter region to initiate transcription and does not have a proofreading function.