Which of the following is a property of DNA polymerase I in prokaryotes?

• A. It synthesizes RNA primers during DNA replication.
• B. It lacks 3' to 5' exonuclease (proofreading) activity.
• C. It is the main enzyme responsible for DNA replication elongation.
• D. It possesses 5' to 3' exonuclease activity.

Answer: (D)

Verified step by step guidance

1. Understand the role of DNA polymerase I in prokaryotic DNA replication. DNA polymerase I is an enzyme involved in DNA replication and repair, but it is not the main enzyme responsible for elongation. Instead, DNA polymerase III performs the majority of DNA synthesis during replication.
2. Review the specific activities of DNA polymerase I. It has three main enzymatic activities: (1) 5' to 3' polymerase activity for synthesizing DNA, (2) 3' to 5' exonuclease activity for proofreading and correcting errors, and (3) 5' to 3' exonuclease activity for removing RNA primers or damaged DNA.
3. Eliminate incorrect options based on the known functions of DNA polymerase I. For example, it does not synthesize RNA primers; this is the role of primase. Additionally, it does have 3' to 5' exonuclease activity for proofreading, so the second option is incorrect. Finally, it is not the main enzyme for elongation, as this is the role of DNA polymerase III.
4. Focus on the correct property of DNA polymerase I. Its unique 5' to 3' exonuclease activity allows it to remove RNA primers laid down by primase and replace them with DNA nucleotides during replication.
5. Conclude that the correct answer is: 'It possesses 5' to 3' exonuclease activity,' as this is a defining feature of DNA polymerase I in prokaryotes.