USA Biology Olympiad (USABO) Practice Exam

What is the significance of obtaining telomeres during chromosome functionality assessment?

1. They regulate gene expression

2. They protect chromosome ends from degradation

3. They assist in centromere formation

4. They are sites of DNA transcription

The correct answer is: They protect chromosome ends from degradation

The significance of obtaining telomeres during chromosome functionality assessment lies primarily in their role of protecting chromosome ends from degradation. Telomeres are repetitive nucleotide sequences located at the ends of chromosomes, serving as protective caps that prevent the loss of important genetic information during DNA replication. When cells divide, the replication process cannot completely duplicate the very ends of linear chromosomes, which can lead to the gradual shortening of chromosomal DNA. Telomeres mitigate this issue by acting as buffers; they ensure that essential coding DNA remains intact. Additionally, without intact telomeres, chromosomes are at risk of fusion, degradation, or activation of DNA damage responses, all of which can lead to genomic instability and various cellular dysfunctions, such as senescence and apoptosis. This protective function is crucial for maintaining chromosome stability, which in turn is essential for proper cell division and function. Therefore, understanding telomeres can provide insights into cellular aging, cancer biology, and genetic disorders, making their assessment a vital component of chromosome functionality evaluation.