Bacterial DNA polymerase I and DNA polymerase III perform different functions during DNA replication.

If mutation inactivated DNA polymerase I in a strain of E. coli, would the cell be able to replicate its DNA? If so, what kind of abnormalities would you expect to find in the cell?

Verified step by step guidance

1. span>Understand the roles of DNA polymerase I and DNA polymerase III in DNA replication. DNA polymerase III is the primary enzyme responsible for the synthesis of new DNA strands, while DNA polymerase I is involved in removing RNA primers and replacing them with DNA.</span
2. span>Consider the impact of inactivating DNA polymerase I. Without DNA polymerase I, the RNA primers used to initiate DNA synthesis would not be removed and replaced with DNA.</span
3. span>Predict the abnormalities that might occur. The presence of RNA segments in the newly synthesized DNA strands could lead to instability and errors in the DNA sequence.</span
4. span>Evaluate whether DNA replication can still occur. DNA polymerase III can still synthesize DNA, so replication can proceed, but the resulting DNA may have RNA fragments and be prone to errors.</span
5. span>Conclude the potential consequences for the cell. The cell might experience issues with DNA integrity and function, potentially leading to cell malfunction or death.</span

Key Concepts

DNA Replication

DNA replication is the biological process by which a cell duplicates its DNA before cell division. This process involves unwinding the double helix and synthesizing new strands complementary to the original ones. Key enzymes, including DNA polymerases, play crucial roles in adding nucleotides to the growing DNA strand and ensuring fidelity in the replication process.

Functions of DNA Polymerase I and III

DNA polymerase I and DNA polymerase III are essential enzymes in E. coli DNA replication. DNA polymerase III is the primary enzyme responsible for synthesizing the new DNA strand during replication, while DNA polymerase I is involved in removing RNA primers and replacing them with DNA. Inactivation of DNA polymerase I would hinder the removal of these primers, leading to potential issues in DNA strand continuity.

Mutations and Their Effects

Mutations are changes in the DNA sequence that can affect gene function and protein production. If DNA polymerase I is inactivated, the cell may still replicate its DNA using DNA polymerase III, but it would likely accumulate RNA primers in the lagging strand. This could lead to abnormalities such as incomplete DNA strands or increased susceptibility to DNA damage, as the cell would struggle to maintain genomic integrity.