DNA replication is carried out by RNA-dependent DNA polymerase

Question

BlackTom AI · Accepted Answer

DNA replication is carried out by DNA-dependent DNA polymerases that use a DNA template to synthesize new DNA strands, so the statement is False.

1) Relevant knowledge points and concepts
- DNA-dependent DNA polymerase: enzyme that reads a DNA template to synthesize complementary DNA; examples: bacterial DNA Pol III (replicative), DNA Pol I (primer removal), eukaryotic DNA polymerases α, δ, ε.
- RNA-dependent DNA polymerase (reverse transcriptase): enzyme that synthesizes DNA using an RNA template; found in retroviruses (e.g., HIV) and in the telomerase complex (telomerase uses an internal RNA as template to extend telomeres).
- Primase: a DNA-dependent RNA polymerase that makes short RNA primers on a DNA template to provide a 3'-OH for DNA polymerases.

2) Step-by-step reasoning
- The process labeled “DNA replication” normally means genome duplication using the existing DNA strands as templates.
- The principal enzymes that carry out the bulk DNA synthesis in cellular replication are DNA-dependent DNA polymerases because they require DNA templates.
- RNA-dependent DNA polymerases synthesize DNA from RNA templates; this is reverse transcription, not canonical DNA replication.
- Although telomerase is an RNA-dependent DNA polymerase, its role is specialized (telomere elongation), not the general replication of the entire genome.

3) Intermediate logic steps (no numeric calculation required)
- If an enzyme requires DNA as template → called DNA-dependent DNA polymerase.
- Cellular genome replication requires enzymes that read DNA templates → therefore DNA-dependent DNA polymerases.
- The statement claims replication is carried out by RNA-dependent DNA polymerase → this contradicts cellular mechanisms.

4) Why the correct answer is correct
- Because standard DNA replication uses DNA templates and DNA-dependent DNA polymerases, the claim that replication is carried out by RNA-dependent DNA polymerase is incorrect.

5) Why the alternative (“True”) is incorrect
- “True” would imply reverse transcriptase performs normal DNA replication; reverse transcriptase performs reverse transcription (RNA→DNA) and is not responsible for genome-wide DNA replication in cells.

Conclusion: The correct evaluation is False, which matches the provided answer.

DNA replication is carried out by RNA-dependent DNA polymerase判断题

类似问题

Which of the following limitations of DNA polymerase is overcome in the process of lagging strand synthesis?

If the template strand of DNA is of the sequence 5’-AGTTGC-3’, what sequence will DNA polymerase synthesise?

“Stabilizes the helix of nucleic acids ahead of the replication fork” would best describe which of the following?

Which of the following enzyme activities is not specifically associated with DNA replication?

What is the role of topoisomerases in eukaryotic DNA replication?

Which of the following statements best explains the mechanism for DNA replication?

Which of the following terms is the least accurate way to describe the process of making new DNA?

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