In prokaryotes, how is the strand without any errors modified after it has been successfully replicated?

In prokaryotes, how is the strand without any errors modified after it has been successfully replicated?

• A. acetylated
• B. phosphorylated
• C. ubiquitinated
• D. methylated

Answer: (D)

In bacteria, the signal that marks replicated DNA for future processes is methylation. After DNA is copied, the parental (template) strand remains methylated, while the newly synthesized strand is initially unmethylated. The enzyme DNA adenine methyltransferase adds methyl groups to adenine in GATC sequences on the new strand over time, so both strands become methylated. This methylation pattern lets the mismatch repair system tell which strand is the template and which is the newly synthesized one to correct any errors. Once replication is complete and the process has finished, the strand that has just been copied ends up being methylated, establishing this mark for future rounds of repair and regulation. Other types of chemical modifications (acetylation, phosphorylation, ubiquitination) serve different roles and are not the signal used for this strand distinction in prokaryotes.

In bacteria, the signal that marks replicated DNA for future processes is methylation. After DNA is copied, the parental (template) strand remains methylated, while the newly synthesized strand is initially unmethylated. The enzyme DNA adenine methyltransferase adds methyl groups to adenine in GATC sequences on the new strand over time, so both strands become methylated. This methylation pattern lets the mismatch repair system tell which strand is the template and which is the newly synthesized one to correct any errors. Once replication is complete and the process has finished, the strand that has just been copied ends up being methylated, establishing this mark for future rounds of repair and regulation. Other types of chemical modifications (acetylation, phosphorylation, ubiquitination) serve different roles and are not the signal used for this strand distinction in prokaryotes.