Telomeres are found at the ends of eukaryotic chromosomes. What is the sequence composition of telomeres?

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1. Telomeres are repetitive nucleotide sequences found at the ends of eukaryotic chromosomes.
2. In most vertebrates, including humans, the telomeric sequence is a simple repeat of the sequence TTAGGG.
3. This sequence is repeated thousands of times to form the telomere structure.
4. The sequence is added by the enzyme telomerase, which extends the 3' end of the DNA strand.
5. Telomeres protect the chromosome ends from degradation and prevent them from being recognized as DNA damage.

Key Concepts

Telomere Structure

Telomeres are repetitive nucleotide sequences located at the ends of eukaryotic chromosomes. They consist primarily of tandem repeats of a specific DNA sequence, typically rich in guanine (G) and adenine (A), which helps protect the chromosome from degradation and prevents the loss of essential genetic information during DNA replication.

Function of Telomeres

The primary function of telomeres is to maintain chromosomal stability by preventing the ends of chromosomes from fusing with each other or being recognized as damaged DNA. This protective role is crucial for cellular aging and the regulation of cell division, as telomeres shorten with each cell division, eventually leading to cellular senescence.

Telomerase Enzyme

Telomerase is an enzyme that adds nucleotide sequences to the ends of telomeres, counteracting their shortening during DNA replication. This enzyme is particularly active in stem cells and cancer cells, allowing them to maintain telomere length and continue dividing, which is a key factor in cellular immortality and tumorigenesis.