Telomere shortening during cell divisions signifies :-

Options

A. Cellular aging
B. Loss of base pairs from chromosomal ends
C. Decrease replication potential of cells
D. All of these

Answer

**Step-by-Step Solution:**

1. **Understanding Telomeres**: Telomeres are repetitive nucleotide sequences located at the ends of chromosomes. They protect the chromosome from deterioration or fusion with neighboring chromosomes.

2. **Telomere Shortening**: With each cell division, telomeres shorten. This is a natural process that occurs because DNA replication cannot completely replicate the ends of linear chromosomes.

3. **Significance of Telomere Shortening**:
- **Cellular Ageing**: As telomeres shorten, cells eventually reach a point where they can no longer divide. This process is known as replicative senescence, which is associated with cellular ageing.
- **Loss of Base Pairs**: Each time a cell divides, a small portion of the telomere is lost, resulting in the loss of base pairs from the chromosomal ends.
- **Decreased Replication Potential**: As telomeres become critically short, the cell's ability to replicate diminishes, leading to decreased replication potential.

4. **Conclusion**: Therefore, telomere shortening during cell divisions signifies cellular ageing, loss of base pairs from chromosomal ends, and decreased replication potential of the cell.

5. **Final Answer**: The correct option is "all of these".

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