RNA polymerase vs DNA polymerase

Question 1

what are the 3 criteria used to compare RNA polymerase & DNA polymerase?

Answer 1

1. requirement of RNA primer during initiation of the process
2. separation of DNA strands during elongation of process
3. having 3’ to 5’ exonuclease proofreading ability

Question 2

how are RNA & DNA polymerase different in terms of requiring RNA primer during initiation of their respective processes?

Answer 2

• RNA polymerase does not require any RNA primer at the start of gene transcription
• while DNA polymerase requires a RNA primer at the start of DNA replication

Question 3

why does RNA polymerase not require any RNA primer at the start of gene transcription?

Answer 3

RNA polymerase is able to synthesise phosphodiester bonds without the need of a pre-existing strand

Question 4

why does DNA polymerase require a RNA primer at the start of DNA replication?

Answer 4

DNA polymerase has a limitation whereby it is only able to synthesise the phosphodiester bond that adds a DNA nucleotide to the free 3’ -OH end of a pre-existing strand

Question 5

how are RNA & DNA polymerase different in the separation of DNA strands during elongation of their respective processes?

Answer 5

• RNA polymerase is able to separate the double stranded DNA by disrupting the hydrogen bonds between complementary base pairs
• whereas DNA polymerase requires helicase to separate the double helix of DNA as it is unable to do so

Question 6

how are RNA & DNA polymerase different in terms of having 3’ to 5’ exonuclease proof-reading ability?

Answer 6

• RNA polymerase lacks the ability,
• while DNA polymerase has the ability, and is able to correct any mismatched bases to ensure accurate DNA replication