In prokaryotic DNA replication, DNA polymerase I is characterized by which enzymatic activities?

• A. It has only $5\text{'}-3\text{'}$ polymerase activity and no exonuclease activity.
• B. It has $3\text{'}-5\text{'}$ polymerase activity, allowing synthesis in the reverse direction.
• C. It has $5\text{'}-3\text{'}$ polymerase activity plus both $3\text{'}-5\text{'}$ and $5\text{'}-3\text{'}$ exonuclease activities.
• D. It has $5\text{'}-3\text{'}$ polymerase activity and only $5\text{'}-3\text{'}$ exonuclease activity (no proofreading).

Answer: (C)

Verified step by step guidance

1. Recall that DNA polymerase I in prokaryotes is involved in DNA replication and repair, and it has multiple enzymatic activities that contribute to these functions.
2. Identify the polymerase activity direction: DNA polymerase I synthesizes DNA in the 5' to 3' direction, which is the standard direction for DNA synthesis.
3. Understand exonuclease activities: DNA polymerase I has two exonuclease activities—one that removes nucleotides in the 3' to 5' direction (proofreading activity) and another in the 5' to 3' direction (important for removing RNA primers).
4. Combine these activities to characterize DNA polymerase I: it has 5' to 3' polymerase activity, 3' to 5' exonuclease activity for proofreading, and 5' to 3' exonuclease activity for primer removal.
5. Use this information to evaluate the answer choices, selecting the one that correctly states DNA polymerase I has 5' to 3' polymerase activity plus both 3' to 5' and 5' to 3' exonuclease activities.