What is the Difference Between DNA Dependent DNA Polymerase and DNA Dependent RNA Polymerase

The key difference between DNA dependent DNA polymerase and DNA dependent RNA polymerase is that DNA dependent DNA polymerase catalyzes the synthesis of a double-stranded DNA molecule during DNA replication while DNA dependent RNA polymerase catalyzes the synthesis of a single-stranded RNA molecule mainly during transcription.

DNA is the genetic material of humans and of almost all living organisms. It is a polymer of two polynucleotide chains that coil around each other, forming a double helical structure. With reference to DNA, DNA polymerase and RNA polymerase are two enzymes that function in a DNA dependent manner. Both enzymes are extremely important during DNA replication and transcription.

CONTENTS

1. Overview and Key Difference
2. What is DNA Dependent DNA Polymerase
3. What is DNA Dependent RNA Polymerase
4. Similarities – DNA Dependent DNA Polymerase and DNA Dependent RNA Polymerase
5. DNA Dependent DNA Polymerase vs DNA Dependent RNA Polymerase in Tabular Form
6. Summary – DNA Dependent DNA Polymerase vs DNA Dependent RNA Polymerase

What is DNA Dependent DNA Polymerase?

DNA-dependent DNA polymerase is an enzyme that synthesizes new DNA molecules in the process of DNA replication. New DNA gets synthesized from DNA nucleotides at the S phase of the interphase of cell division to form a double-stranded DNA molecule. DNA-dependent DNA polymerase uses a primer sequence to synthesize the complementary daughter strand during DNA replication.

DNA-dependent DNA polymerase is also known as DNA polymerase, and it has many subtypes. This enzyme always polymerizes in the 5’ to 3’ direction and requires a template to start polymerization. In addition to its main function, DNA-dependent DNA polymerase also takes part in proofreading and DNA repair functions.

What is DNA Dependent RNA Polymerase?

DNA dependent RNA polymerase is an enzyme that synthesizes RNA molecules from DNA in the process of transcription. Here, DNA dependent RNA polymerase adds RNA nucleotides in the direction of 5’ to 3’. The synthesizing RNA could be either mRNA, rRNa, or tRNA.

DNA dependent RNA polymerase does not need a synthetic DNA primer to start adding RNA nucleotides; hence it works independently. It recognizes the promoter region of the template strand of DNA to commence transcription. In eukaryotic cells, DNA dependent RNA polymerase is of five types. (I to V). Out of the five types, DNA dependent RNA polymerase I is responsible for 50 % of transcription process. Prokaryotes consist of only a single type of RNA polymerase.

What are the Similarities Between DNA Dependent DNA Polymerase and DNA Dependent RNA Polymerase?

• DNA dependent DNA polymerase and DNA dependent RNA polymerase are enzymes.
• In prokaryotes, both enzymes are distributed in the cell cytoplasm.
• In eukaryotes, both enzymes are distributed in the nucleus.
• Moreover, both perform polymerization functions.
• These enzymes form phosphodiester bonds between nucleotides.
• Both enzymes function in the direction of 5’ to 3’.
• Both types of polymerases are important for cell division and protein synthesis.

What is the Difference Between DNA Dependent DNA Polymerase and DNA Dependent RNA Polymerase?

DNA dependent DNA polymerase catalyzes the DNA replication process in order to produce a double-stranded DNA molecule, while DNA dependent RNA polymerase catalyzes the transcription process in order to produce a single-stranded RNA molecule. Thus, this is the key difference between DNA dependent DNA polymerase and DNA dependent RNA polymerase. Moreover, DNA dependent DNA polymerase requires a primer to initiate polymerization, while DNA dependent RNA polymerase does not require a primer to initiate polymerization.

The following table summarizes the difference between DNA dependent DNA polymerase and DNA dependent RNA polymerase.

Summary – DNA Dependent DNA Polymerase vs DNA Dependent RNA Polymerase

DNA dependent DNA polymerase is an enzyme that synthesizes new DNA molecules in the process of DNA replication. DNA dependent RNA polymerase is an enzyme that synthesizes RNA molecules from DNA in the process of transcription. DNA dependent DNA polymerase produces a double-stranded DNA molecule, while DNA dependent RNA polymerase produces a single-stranded RNA molecule. Both enzymes form phosphodiester bonds between nucleotides and function in the direction of 5’ to 3’. So, this summarizes the difference between DNA Dependent DNA Polymerase and DNA Dependent RNA Polymerase.

Reference:

1. Thapa, Rajat. “DNA Polymerase- Definition, Properties, Structure, Types, Functions.” The Biology Notes, 28 Feb. 2022.
2. Thapa, Rajat. “RNA Polymerase- Definition, Properties, Structure, Types, Functions.” The Biology Notes, 28 Feb. 2022.

Image Courtesy:

1. “DNA Polymerase DNA Replication”  By Christinelmiller – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “0338 RNA Polymerase Binding” By OpenStax – (CC BY 4.0) via Commons Wikimedia