In: Biology
You discover a new eukaryotic organism that has a very large genome with DNA bound to histones in the form of chromatin, but has a single circular chromosome. Would this organism be likely to have a telomerase enzyme? Explain your reasoning.
Answer : No; This organism is unlikely to have a telomerase enzyme
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The DNA strands become slightly shorter after each replication. To prevent this shortening of chromosomes the free ends of the chromosomes contain specific protein-DNA structures called Telomeres. Telomeres protect the ends of the chromosome from end-to-end fusion with neighbouring chromosomes and thus prevents DNA damnage. As the chromosomes replicate, the telomeres shorten.
There is an enzyme called Telomerase, which can replicate telomere sequences and prevent the telomeres from getting shorter i.e, Telomerases maintens of the length of telomeres by the addition of guanine-rich sequences.
We know that telomeres are present at the terminal end of a chromosome. In circular chromosomes, there is no terminal end. So, there is no telomers and there is no telomerase enzyme.