Telomeres are sequences of repeated nucleotides at the end of a chromosome that do not code for genes. What term describes these regions?

• A. Centromeres
• B. Telomeres
• C. Exons
• D. Promoters

Answer: (B)

End regions of chromosomes are protected by telomeres, repetitive noncoding DNA that cap chromosome ends to prevent loss of important genes during replication. That description fits because telomeres sit at the very ends of chromosomes and do not code for proteins or genes. They differ from centromeres, which are the middle region essential for proper chromosome segregation during cell division; from exons, which are the coding portions of genes; and from promoters, which are DNA sequences that regulate the start of transcription. Telomeres help maintain genome stability and shorten with cell divisions, linking to aging and cellular lifespan.