Question

Telomerase acts as a cellular reverse transcriptase that provides the active site for:

• A. RNA-dependent DNA synthesis
• B. DNA-dependent RNA synthesis
• C. RNA-dependent RNA synthesis
• D. DNA-dependent DNA synthesis

Hint:

Remember the enzyme naming convention: The first part describes the template, and the second part describes the product being synthesized. "RNA-dependent DNA synthesis" means "uses RNA as a template to synthesize DNA." This is the definition of reverse transcription, the function of telomerase.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Telomerase, a ribonucleoprotein enzyme, maintains telomere length, protecting the ends of eukaryotic chromosomes.
It prevents chromosome shortening during DNA replication.
Reverse transcriptase synthesizes DNA from an RNA template.
Step 2: Detailed Explanation:
Telomerase function explained:


Telomerase contains an RNA molecule, which acts as a template.

Using this RNA template, it synthesizes DNA, adding repetitive sequences to the DNA's 3' end.

This RNA-template-driven DNA synthesis is termed RNA-dependent DNA synthesis.

Analyzing other synthesis types:


DNA-dependent RNA synthesis (transcription) is performed by RNA polymerase.

RNA-dependent RNA synthesis is performed by RNA replicase, found in certain RNA viruses.

DNA-dependent DNA synthesis (standard DNA replication) is performed by DNA polymerase.

Step 3: Final Answer:
Telomerase, a reverse transcriptase synthesizing DNA from an RNA template, exhibits RNA-dependent DNA synthesis.