Question

Telomerase, an RNA-protein complex, adds telomeres at the end of chromosomes. What kind of enzymatic activity does it possess?

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

Hint:

Telomerase is a unique enzyme that carries its own RNA template and is an example of an RNA-dependent DNA polymerase, unlike most polymerases that use DNA as a template.

Answer 1

The Correct Option is C

Telomerase is an RNA-protein complex that adds repetitive nucleotide sequences, known as telomeres, to the ends of chromosomes. It is unique because it carries an RNA molecule that serves as a template for the addition of DNA sequences. This makes telomerase an RNA-dependent DNA polymerase, as it synthesizes DNA from an RNA template.

Step 1: Understanding the enzymatic activity

Telomerase uses its RNA component as a template to add telomeric sequences to the ends of chromosomes. This function classifies it as an RNA-dependent DNA polymerase, which means it synthesizes DNA based on the RNA template it carries.

Step 2: Explanation of the options

• DNA-dependent DNA polymerase: This type of polymerase synthesizes DNA from a DNA template, but it is not related to telomerase.
• DNA-dependent RNA polymerase: This enzyme synthesizes RNA from a DNA template, which is not the function of telomerase.
• RNA-dependent DNA polymerase: This is the correct activity of telomerase. It synthesizes DNA using an RNA template, which is characteristic of reverse transcriptase enzymes.
• RNA-dependent RNA polymerase: This enzyme synthesizes RNA from an RNA template, but this is not the function of telomerase.

Thus, the correct answer is RNA-dependent DNA polymerase.