What is the role of telomeres in chromosomes?

• A. They catalyze DNA replication
• B. They protect chromosome ends from degradation
• C. They are responsible for protein synthesis
• D. They assist in the immune response

Answer: (B)

Telomeres play a crucial role in protecting the ends of chromosomes from deterioration and fusion with neighboring chromosomes. Their structure consists of repetitive nucleotide sequences that form a protective cap at the ends of linear chromosomes. This is especially important because, during DNA replication, enzymes that replicate DNA cannot fully replicate the ends of linear chromosomes. Over time, as cells divide, these telomeres shorten, which eventually signals the cell to stop dividing and enter senescence or programmed cell death. Therefore, the primary function of telomeres is to maintain the integrity of genetic information by preventing the loss of essential coding sequences from the chromosomes and protecting them from damage.

The other choices relate to different biological functions that do not pertain to telomeres. Catalyzing DNA replication is the role of DNA polymerases, whereas protein synthesis is facilitated by ribosomes and related cellular machinery. The immune response involves various cells and molecules, including antibodies and immune cells, rather than telomeres themselves.