Question

Which is a characteristic of DNA sequences at the telomeres?

1) One strand protrudes beyond the other, creating some single-stranded DNA at the end.
2) all of the above
3) They consist of cytosine and adenine nucleotides
4) The consist of repeated sequences

Answer 1

The characteristic of DNA sequences at telomeres is that they consist of repeated sequences of the noncoding TTAGGG sequence in humans. These protect chromosome ends during cell division, and telomerase helps maintain them by adding to the 3' end of the DNA strand.

Step-by-step explanation:

The characteristic of DNA sequences at the telomeres is that they consist of repeated sequences. Specifically, in humans, the sequence TTAGGG is repeated between 100 to 1000 times. These repetitive sequences are critical for protecting the chromosome ends during cell division and are not coding for any particular gene. The enzyme telomerase plays a key role in adding these sequences to the ends of chromosomes, using an RNA template that it carries to extend the 3' end of the DNA, allowing the lagging strand to be sufficiently elongated before DNA polymerase adds the final nucleotides.

This process ensures that the crucial genetic information is not lost during DNA replication.