Why do most bacteria not need telomerase to replicate their genomes?

• A. They lack DNA polymerase and instead copy DNA using ribosomes, eliminating the need for telomere maintenance.
• B. They replicate their DNA using RNA-dependent RNA polymerase, which prevents end-replication problems.
• C. They have linear chromosomes with telomeres protected by telomerase-independent shelterin complexes identical to those in eukaryotes.
• D. Their chromosomes are typically circular, so they do not have chromosome ends (telomeres) that shorten during DNA replication.

Answer: (D)

Verified step by step guidance

1. Understand the role of telomerase: Telomerase is an enzyme that extends the ends of linear chromosomes (telomeres) to prevent their shortening during DNA replication, which is a problem in eukaryotic cells.
2. Recognize the structure of bacterial chromosomes: Most bacteria have circular chromosomes rather than linear ones, meaning their DNA forms a closed loop without free ends.
3. Analyze the implication of circular chromosomes: Because circular chromosomes do not have ends, the typical 'end-replication problem' that occurs in linear chromosomes does not exist in bacteria.
4. Connect the absence of chromosome ends to the need for telomerase: Since bacteria lack chromosome ends, they do not require telomerase to maintain telomeres during DNA replication.
5. Conclude that bacterial DNA replication uses DNA polymerase on circular DNA, avoiding telomere shortening and eliminating the need for telomerase.