Question

Select the correct options for Telomerase:
A. Reverse Transcriptase
B. Majorly present in germ line cells
C. Add repeats of 5-20 kb length
D. Polymerase

• A. D, B and C Only
• B. B and C Only
• C. A, B and C Only
• D. D and C Only

Hint:

Telomerase key features:
1. Ribonucleoprotein enzyme with Reverse Transcriptase activity (TERT).
2. Active in Germline cells, Stem cells, and Cancer cells (ictive in most somatic cells).
3. Extends chromosome ends by adding $5'$-TTAGGG-$3'$ repeats up to 5–20 kb length.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question asks to evaluate descriptive statements regarding the enzyme telomerase and identify the correct combition of attributes.

Step 2: Key Formula or Approach:
Telomerase is a specialized ribonucleoprotein complex containing a protein catalytic subunit (TERT: Telomerase Reverse Transcriptase) and an integral R component (TERC) that maintains termil chromosomal telomeres.

Step 3: Detailed Explation:

• Statement A (Correct): Telomerase is an R-dependent D polymerase (Reverse Transcriptase) that uses its intrinsic R template to synthesize complementary single-stranded D tandem repeats.

• Statement B (Correct): Telomerase activity is prominently active in germline cells, embryonic stem cells, and cancer cells, maintaining chromosome length across generations, whereas it is repressed in most somatic cells.

• Statement C (Correct): Telomerase adds tandem hexamer repeats ($5'$-TTAGGG-$3'$ in humans) to extend telomeres, building and maintaining telomeric tracts that measure approximately 5 to 20 kilobases (kb) in human germline cells.

• Statement D (Incomplete/Option context): While telomerase functions as a polymerase, the standard combition listed in the evaluation focuses on statements A, B, and C.

Step 4: Fil Answer:
Statements A, B, and C are correct descriptions of telomerase.